About | BLOGS | Portfolio | Misc | Recommended | What's New | What's Hot

About | BLOGS | Portfolio | Misc | Recommended | What's New | What's Hot


Bibliography Options Menu

26 Mar 2019 at 01:47
Hide Abstracts   |   Hide Additional Links
Long bibliographies are displayed in blocks of 100 citations at a time. At the end of each block there is an option to load the next block.

Bibliography on: Paleontology Meets Genomics — Sequencing Ancient DNA


Robert J. Robbins is a biologist, an educator, a science administrator, a publisher, an information technologist, and an IT leader and manager who specializes in advancing biomedical knowledge and supporting education through the application of information technology. More About:  RJR | OUR TEAM | OUR SERVICES | THIS WEBSITE

RJR: Recommended Bibliography 26 Mar 2019 at 01:47 Created: 

Paleontology Meets Genomics — Sequencing Ancient DNA

The ideas behind Jurassic Park have become real, kinda sorta. It is now possible to retrieve and sequence DNA from ancient specimens. Although these sequences are based on poor quality DNA and thus have many inferential steps (i,e, the resulting sequence is not likely to be a perfect replica of the living DNA), the insights to be gained from paleosequentcing are nonetheless great. For example, paleo-sequencing has shown that Neanderthal DNA is sufficiently different from human DNA as to be reasonably considered as coming from a different species.

Created with PubMed® Query: "ancient DNA" OR "ancient genome" OR paleogenetic OR paleogenetics NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2019-03-20

Di Maida G, Mannino MA, Krause-Kyora B, et al (2019)

Radiocarbon dating and isotope analysis on the purported Aurignacian skeletal remains from Fontana Nuova (Ragusa, Italy).

PloS one, 14(3):e0213173 pii:PONE-D-18-23492.

Proving voyaging at sea by Palaeolithic humans is a difficult archaeological task, even for short distances. In the Mediterranean, a commonly accepted sea crossing is that from the Italian Peninsula to Sicily by anatomically modern humans, purportedly of the Aurignacian culture. This claim, however, was only supported by the typological attribution to the Aurignacian of the lithic industries from the insular site of Fontana Nuova. AMS radiocarbon dating undertaken as part of our research shows that the faunal remains, previously considered Aurignacian, actually date to the Holocene. Absolute dating on dentinal collagen also attributes the human teeth from the site to the early Holocene, although we were unable to obtain ancient DNA to evaluate their ancestry. Ten radiocarbon dates on human and other taxa are comprised between 9910-9700 cal. BP and 8600-8480 cal. BP, indicating that Fontana Nuova was occupied by Mesolithic and not Aurignacian hunter-gatherers. Only a new study of the lithic assemblage could establish if the material from Fontana Nuova is a mixed collection that includes both late Upper Palaeolithic (Epigravettian) and Mesolithic artefacts, as can be suggested by taking into account both the results of our study and of the most recent reinterpretation of the lithics. Nevertheless, this research suggests that the notion that Aurignacian groups were present in Sicily should now be revised. Another outcome of our study is that we found that three specimens, attributed on grounds both of morphological and ZooMS identifications to Cervus elaphus, had δ13C values significantly higher than any available for such species in Europe.

RevDate: 2019-03-19

Weyrich LS, Farrer AG, Eisenhofer R, et al (2019)

Laboratory contamination over time during low-biomass sample analysis.

Molecular ecology resources [Epub ahead of print].

Bacteria are not only ubiquitous on earth but can also be incredibly diverse within clean laboratories and reagents. The presence of both living and dead bacteria in laboratory environments and reagents is especially problematic when examining samples with low endogenous content (e.g. skin swabs, tissue biopsies, ice, water, degraded forensic samples, or ancient material), where contaminants can outnumber endogenous microorganisms within samples. The contribution of contaminants within high-throughput studies remains poorly understood because of the relatively low number of contaminant surveys. Here, we examined 144 negative control samples (extraction blank and no-template amplification controls) collected in both typical molecular laboratories and an ultraclean ancient DNA laboratory over five years to characterize long-term contaminant diversity. We additionally compared the contaminant content within a homemade silica-based extraction method, commonly used to analyse low-endogenous samples, with a widely used commercial DNA extraction kit. The contaminant taxonomic profile of the ultraclean ancient DNA laboratory was unique compared to the modern molecular biology laboratories, and changed over time according to researchers, month, and season. The commercial kit contained higher microbial diversity and several human-associated taxa in comparison to the homemade silica extraction protocol. We recommend a minimum of two strategies to reduce the impacts of laboratory contaminants within low-biomass metagenomic studies: 1) extraction blank controls should be included and sequenced with every batch of extractions and 2) the contributions of laboratory contamination should be assessed and reported in each high-throughput metagenomic study. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-19

Eisenhofer R, LS Weyrich (2019)

Assessing alignment-based taxonomic classification of ancient microbial DNA.

PeerJ, 7:e6594 pii:6594.

The field of palaeomicrobiology-the study of ancient microorganisms-is rapidly growing due to recent methodological and technological advancements. It is now possible to obtain vast quantities of DNA data from ancient specimens in a high-throughput manner and use this information to investigate the dynamics and evolution of past microbial communities. However, we still know very little about how the characteristics of ancient DNA influence our ability to accurately assign microbial taxonomies (i.e. identify species) within ancient metagenomic samples. Here, we use both simulated and published metagenomic data sets to investigate how ancient DNA characteristics affect alignment-based taxonomic classification. We find that nucleotide-to-nucleotide, rather than nucleotide-to-protein, alignments are preferable when assigning taxonomies to short DNA fragment lengths routinely identified within ancient specimens (<60 bp). We determine that deamination (a form of ancient DNA damage) and random sequence substitutions corresponding to ∼100,000 years of genomic divergence minimally impact alignment-based classification. We also test four different reference databases and find that database choice can significantly bias the results of alignment-based taxonomic classification in ancient metagenomic studies. Finally, we perform a reanalysis of previously published ancient dental calculus data, increasing the number of microbial DNA sequences assigned taxonomically by an average of 64.2-fold and identifying microbial species previously unidentified in the original study. Overall, this study enhances our understanding of how ancient DNA characteristics influence alignment-based taxonomic classification of ancient microorganisms and provides recommendations for future palaeomicrobiological studies.

RevDate: 2019-03-19

Abondio P, Sazzini M, Garagnani P, et al (2019)

The Genetic Variability of APOE in Different Human Populations and Its Implications for Longevity.

Genes, 10(3): pii:genes10030222.

Human longevity is a complex phenotype resulting from the combinations of context-dependent gene-environment interactions that require analysis as a dynamic process in a cohesive ecological and evolutionary framework. Genome-wide association (GWAS) and whole-genome sequencing (WGS) studies on centenarians pointed toward the inclusion of the apolipoprotein E (APOE) polymorphisms ε2 and ε4, as implicated in the attainment of extreme longevity, which refers to their effect in age-related Alzheimer's disease (AD) and cardiovascular disease (CVD). In this case, the available literature on APOE and its involvement in longevity is described according to an anthropological and population genetics perspective. This aims to highlight the evolutionary history of this gene, how its participation in several biological pathways relates to human longevity, and which evolutionary dynamics may have shaped the distribution of APOE haplotypes across the globe. Its potential adaptive role will be described along with implications for the study of longevity in different human groups. This review also presents an updated overview of the worldwide distribution of APOE alleles based on modern day data from public databases and ancient DNA samples retrieved from literature in the attempt to understand the spatial and temporal frame in which present-day patterns of APOE variation evolved.

RevDate: 2019-03-18

Villalba-Mouco V, van de Loosdrecht MS, Posth C, et al (2019)

Survival of Late Pleistocene Hunter-Gatherer Ancestry in the Iberian Peninsula.

Current biology : CB pii:S0960-9822(19)30145-9 [Epub ahead of print].

The Iberian Peninsula in southwestern Europe represents an important test case for the study of human population movements during prehistoric periods. During the Last Glacial Maximum (LGM), the peninsula formed a periglacial refugium [1] for hunter-gatherers (HGs) and thus served as a potential source for the re-peopling of northern latitudes [2]. The post-LGM genetic signature was previously described as a cline from Western HG (WHG) to Eastern HG (EHG), further shaped by later Holocene expansions from the Near East and the North Pontic steppes [3-9]. Western and central Europe were dominated by ancestry associated with the ∼14,000-year-old individual from Villabruna, Italy, which had largely replaced earlier genetic ancestry, represented by 19,000-15,000-year-old individuals associated with the Magdalenian culture [2]. However, little is known about the genetic diversity in southern European refugia, the presence of distinct genetic clusters, and correspondence with geography. Here, we report new genome-wide data from 11 HGs and Neolithic individuals that highlight the late survival of Paleolithic ancestry in Iberia, reported previously in Magdalenian-associated individuals. We show that all Iberian HGs, including the oldest, a ∼19,000-year-old individual from El Mirón in Spain, carry dual ancestry from both Villabruna and the Magdalenian-related individuals. Thus, our results suggest an early connection between two potential refugia, resulting in a genetic ancestry that survived in later Iberian HGs. Our new genomic data from Iberian Early and Middle Neolithic individuals show that the dual Iberian HG genomic legacy pertains in the peninsula, suggesting that expanding farmers mixed with local HGs. VIDEO ABSTRACT.

RevDate: 2019-03-15

Hahn C (2019)

Assembly of Ancient Mitochondrial Genomes Without a Closely Related Reference Sequence.

Methods in molecular biology (Clifton, N.J.), 1963:195-213.

Recent methodological advances have transformed the field of ancient DNA (aDNA). Basic bioinformatics skills are becoming essential requirements to process and analyze the sheer amounts of data generated by current aDNA studies and in biomedical research in general. This chapter is intended as a practical guide to the assembly of ancient mitochondrial genomes, directly from genomic DNA-derived next-generation sequencing (NGS) data, specifically in the absence of closely related reference genomes. In a hands-on tutorial suitable for readers with little to no prior bioinformatics experience, we reconstruct the mitochondrial genome of a woolly mammoth deposited ~45,000 years ago. We introduce key software tools and outline general strategies for mitogenome assembly, including the critical quality assessment of assembly results without a reference genome.

RevDate: 2019-03-15

Renaud G, Schubert M, Sawyer S, et al (2019)

Authentication and Assessment of Contamination in Ancient DNA.

Methods in molecular biology (Clifton, N.J.), 1963:163-194.

Contamination from both present-day humans and postmortem microbial sources is a common challenge in ancient DNA studies. Here we present a suite of tools to assist in the assessment of contamination in ancient DNA data sets. These tools perform standard tests of authenticity of ancient DNA data including detecting the presence of postmortem damage signatures in sequence alignments and quantifying the amount of present-day human contamination.

RevDate: 2019-03-15

Nichols RV, Curd E, Heintzman PD, et al (2019)

Targeted Amplification and Sequencing of Ancient Environmental and Sedimentary DNA.

Methods in molecular biology (Clifton, N.J.), 1963:149-161.

All organisms release their DNA into the environment through processes such as excretion and the senescence of tissues and limbs. This DNA, often referred to as environmental DNA (eDNA) or sedimentary ancient DNA (sedaDNA), can be recovered from both present-day and ancient soils, fecal samples, bodies of water and lake cores, and even air. While eDNA is a potentially useful record of past and present biodiversity, several challenges complicate data generation and interpretation of results. Most importantly, eDNA samples tend to be highly taxonomically mixed, and the target organism or group of organisms may be present at very low abundance within this mixture. To overcome this challenge, enrichment approaches are often used to target specific taxa of interest. Here, we describe a protocol to amplify metabarcodes or short, variable loci that identify lineages within broad taxonomic groups (e.g., plants, mammals), using the polymerase chain reaction (PCR) with established generic "barcode" primers. We also provide a catalog of animal and plant barcode primers that, because they target relatively short fragments of DNA, are potentially suitable for use with degraded DNA.

RevDate: 2019-03-15

Wutke S, A Ludwig (2019)

Targeted PCR Amplification and Multiplex Sequencing of Ancient DNA for SNP Analysis.

Methods in molecular biology (Clifton, N.J.), 1963:141-147.

The analysis of single-nucleotide polymorphisms (SNPs) has proven to be advantageous for addressing variation within samples of highly degraded or low-quality DNA samples. This is because only short fragments need to be amplified to analyze SNPs, and this can be achieved by multiplex PCR. Here, we present a sensitive method for the targeted sequencing of SNP loci that requires only small amounts of template DNA. The approach combines multiplex amplification of very short fragments covering SNP positions followed by sample barcoding and next-generation sequencing. This method allows generation of data from large sample sets of poorly preserved specimens, such as fossil remains, forensic samples, and museum specimens. The approach is cost-effective, rapid, and applicable to forensics, population genetics, and phylogenetic research questions.

RevDate: 2019-03-15

Paijmans JLA, González Fortes G, DW Förster (2019)

Application of Solid-State Capture for the Retrieval of Small-to-Medium Sized Target Loci from Ancient DNA.

Methods in molecular biology (Clifton, N.J.), 1963:129-139.

Genetic studies that include ancient samples are often hampered by the low amount of endogenous DNA that ancient samples often contain, relative to co-extracted "contaminant" DNA from other organisms. One approach to mitigate this challenge is to perform hybridization-based capture of target genomic regions using DNA or RNA baits. Such baits are designed to have high sequence similarity to the target genomic regions and can reduce the off-target fraction in DNA sequencing libraries. Here, we present a protocol to use Agilent SureSelect microarrays to enrich ancient DNA libraries for small-to-medium-sized target loci, such as mitochondrial genomes, from ancient DNA extracts. The protocol that we present builds on previously published work by introducing improvements that improve recovery of short DNA fragments while minimizing the cost and duration of the experiment.

RevDate: 2019-03-15

Soares AER (2019)

Hybridization Capture of Ancient DNA Using RNA Baits.

Methods in molecular biology (Clifton, N.J.), 1963:121-128.

The majority of DNA recovered from ancient remains is derived from organisms that colonize the remains post-mortem, such as soil microbes, or from contaminants, such as DNA from living humans. Additionally, some ancient DNA research projects aim to target specific genomic regions, such as mitochondrial genomes or variable single nucleotide polymorphisms (SNPs). To overcome the challenge of targeting specific fragments of DNA from within a complex DNA extract, methods have been developed to enrich ancient DNA extracts for target DNA relative to nontarget DNA. This chapter describes a method for target DNA enrichment that uses hybridization to biotinylated RNA baits to capture and amplify specific ancient DNA fragments from within the pool of extracted fragments.

RevDate: 2019-03-15

Snyder-Mackler N, Voyles T, J Tung (2019)

Generating RNA Baits for Capture-Based Enrichment.

Methods in molecular biology (Clifton, N.J.), 1963:107-120.

Capture-based enrichment techniques have revolutionized genomic analysis of species and populations for which only low-quality or contaminated DNA samples (e.g., ancient DNA, noninvasively collected DNA, environmental DNA) are available. This chapter outlines an optimized laboratory protocol for generating RNA "baits" for genome-wide capture of target DNA from a larger pool of DNA. This method relies on the in vitro transcription of biotinylated RNA baits, which has the dual benefit of eliminating the high cost of synthesizing custom baits and producing a bait set that targets the majority of regions genome-wide. We provide a detailed protocol for the three main steps involved in bait library construction: (1) making a DNA library from a high-quality DNA sample for the organism of interest or a closely related species; (2) using duplex-specific nuclease digestion to reduce the representation of repetitive regions in the DNA library; and (3) performing in vitro transcription of the repetitive region-depleted DNA library to generate biotinylated RNA baits. Where applicable, we include notes and recommendations based on our own experiences.

RevDate: 2019-03-15

González Fortes G, JLA Paijmans (2019)

Whole-Genome Capture of Ancient DNA Using Homemade Baits.

Methods in molecular biology (Clifton, N.J.), 1963:93-105.

For many archaeological and paleontological samples, the relative content of endogenous compared to contaminant DNA is low. In such cases, enriching sequencing libraries for endogenous DNA, prior to sequencing can make the final research project more cost-effective. Here, we present an in-solution enrichment protocol based on homemade baits that can be applied to recover complete nuclear genomes from ancient remains. The approach is based on the preparation of DNA baits by biotinylated adapter ligation. The procedure has been developed for use with human remains but can be adapted to other species or target regions by choosing the appropriate template DNA from which to build the capture baits. By using homemade rather than commercially acquired baits, this protocol may offer increased flexibility and cost efficiency.

RevDate: 2019-03-15

Gansauge MT, M Meyer (2019)

A Method for Single-Stranded Ancient DNA Library Preparation.

Methods in molecular biology (Clifton, N.J.), 1963:75-83.

Genomic library preparation from highly degraded DNA is more efficient when library molecules are prepared separately from the complementary strands of DNA fragments. We describe a protocol in which libraries are constructed from single DNA strands in a three-step procedure: single-stranded ligation of the first adapter with T4 DNA ligase in the presence of a splinter oligonucleotide, copying of the DNA strand with a proofreading polymerase, and blunt-end ligation of the second double-stranded adapter with T4 DNA ligase.

RevDate: 2019-03-15

Henneberger K, Barlow A, JLA Paijmans (2019)

Double-Stranded Library Preparation for Ancient and Other Degraded Samples.

Methods in molecular biology (Clifton, N.J.), 1963:65-73.

High-throughput sequencing (HTS) allows fast and cost-efficient sequencing of ancient DNA (aDNA) without prior information about what sequences should be targeted. One necessary step for HTS is the preparation of a sequencing library. Commercial kits are available for this purpose, but many of these are not suitable for aDNA or other types of damaged DNA. Here, we outline a protocol for HTS library preparation that is optimized for ancient DNA. We report the library conversion rate for a range of input template and adapter concentrations. Our results show that the protocol performs at a high efficiency.

RevDate: 2019-03-15

Campos PF, MTP Gilbert (2019)

DNA Extraction from Keratin and Chitin.

Methods in molecular biology (Clifton, N.J.), 1963:57-63.

DNA extracted from keratinous and chitinous materials can be a useful source of genetic information. To effectively liberate the DNA from these materials, buffers containing relatively high levels of DTT, proteinase K, and detergent are recommended, followed by purification using either silica column or organic methods.

RevDate: 2019-03-15

Wales N, L Kistler (2019)

Extraction of Ancient DNA from Plant Remains.

Methods in molecular biology (Clifton, N.J.), 1963:45-55.

Ancient plant remains from archaeological sites, paleoenvironmental contexts, and herbaria provide excellent opportunities for interrogating plant genetics over Quaternary timescales using ancient DNA (aDNA)-based analyses. A variety of plant tissues, preserved primarily by desiccation and anaerobic waterlogging, have proven to be viable sources of aDNA. Plant tissues are anatomically and chemically diverse and therefore require optimized DNA extraction approaches. Here, we describe a plant DNA isolation protocol that performs well in most contexts. We include recommendations for optimization to retain the very short DNA fragments that are expected to be preserved in degraded tissues.

RevDate: 2019-03-15

Epp LS, Zimmermann HH, KR Stoof-Leichsenring (2019)

Sampling and Extraction of Ancient DNA from Sediments.

Methods in molecular biology (Clifton, N.J.), 1963:31-44.

Environmental DNA preserved in sediments is rapidly gaining importance as a tool in paleoecology. Sampling procedures for sedimentary ancient DNA (sedaDNA) have to be well planned to ensure clean subsampling of the inside of sediment cores and avoid introducing contamination. Additionally, ancient DNA extraction protocols may need to be optimized for the recovery of DNA from sediments, which may contain inhibitors. Here we describe procedures for subsampling both nonfrozen and frozen sediment cores, and we describe an efficient method for ancient DNA extraction from such samples.

RevDate: 2019-03-15

Dabney J, M Meyer (2019)

Extraction of Highly Degraded DNA from Ancient Bones and Teeth.

Methods in molecular biology (Clifton, N.J.), 1963:25-29.

We provide a DNA extraction protocol optimized for the recovery of highly fragmented molecules preserved within bones and teeth. In this method, the hard tissue matrix is degraded using an EDTA/Proteinase K lysis buffer, and the DNA is purified using spin columns with silica membranes. This method efficiently recovers molecules as short as 35 base-pairs long.

RevDate: 2019-03-15

Schroeder H, de Barros Damgaard P, ME Allentoft (2019)

Pretreatment: Improving Endogenous Ancient DNA Yields Using a Simple Enzymatic Predigestion Step.

Methods in molecular biology (Clifton, N.J.), 1963:21-24.

Ancient DNA samples generally contain a mixture of both endogenous and exogenous (contaminant) DNA. The authentic endogenous DNA content varies widely between samples and substrates but usually constitutes only a small fraction of the total DNA, while the remainder comprises contamination deriving from bacteria, fungi, and other microorganisms and in some cases also modern human DNA. Recently, several protocols have been developed to improve access to the endogenous DNA fraction by decreasing the exogenous fraction prior to extraction. The most common of these involve pretreatment with single or multiple washes with weak sodium phosphate or sodium hypochlorite (bleach) solutions, as described in Chapter 2 . Here, we present an alternative, less aggressive pretreatment protocol that uses a brief predigestion step in an EDTA-based lysis buffer to increase the endogenous fraction prior to extraction.

RevDate: 2019-03-15

Korlević P, M Meyer (2019)

Pretreatment: Removing DNA Contamination from Ancient Bones and Teeth Using Sodium Hypochlorite and Phosphate.

Methods in molecular biology (Clifton, N.J.), 1963:15-19.

DNA isolated from ancient bones and teeth comprises a mixture of microbial contamination and DNA from the organism under study. In addition, analyses of ancient human remains are often complicated by contamination with present-day human DNA, which can be introduced during excavation and subsequent handling of the specimens. In most cases, the relative abundance of contaminant DNA is much greater than that of the target organism. Here we present two techniques for reducing the proportion of contaminant DNA in bones and teeth. The first and most efficient technique uses a sodium hypochlorite (bleach) pretreatment to destroy contaminant DNA that may be bound or otherwise attached to the surface of bone/tooth powder. The second, less destructive pretreatment uses a phosphate buffer to release surface-bound DNA.

RevDate: 2019-03-15

Fulton TL, B Shapiro (2019)

Setting Up an Ancient DNA Laboratory.

Methods in molecular biology (Clifton, N.J.), 1963:1-13.

Entering into the world of ancient DNA research is nontrivial. Because the DNA in most ancient specimens is degraded to some extent, the potential is high for contamination of ancient samples, ancient DNA extracts, and genomic sequencing libraries prepared from these extracts with non-degraded DNA from the present-day environment. To minimize the risk of contamination in ancient DNA environments, experimental protocols specific to handling ancient specimens, including those that outline the design and layout of laboratory space, have been introduced. Here, we outline challenges associated with working with ancient samples, including providing guidelines for setting up a new ancient DNA laboratory. We also discuss steps that can be taken at the sample collection and preparation stage to minimize the potential for contamination of ancient DNA experiments with exogenous sources of DNA.

RevDate: 2019-03-15

Rey-Iglesia A, García-Vázquez A, Treadaway EC, et al (2019)

Evolutionary history and palaeoecology of brown bear in North-East Siberia re-examined using ancient DNA and stable isotopes from skeletal remains.

Scientific reports, 9(1):4462 pii:10.1038/s41598-019-40168-7.

Over 60% of the modern distribution range of brown bears falls within Russia, yet palaeoecological data from the region remain scarce. Complete modern Russian brown bear mitogenomes are abundant in the published literature, yet examples of their ancient counterparts are absent. Similarly, there is only limited stable isotopic data of prehistoric brown bears from the region. We used ancient DNA and stable carbon (δ13C) and nitrogen (δ15N) isotopes retrieved from five Pleistocene Yakutian brown bears (one Middle Pleistocene and four Late Pleistocene), to elucidate the evolutionary history and palaeoecology of the species in the region. We were able to reconstruct the complete mitogenome of one of the Late Pleistocene specimens, but we were unable to assign it to any of the previously published brown bear mitogenome clades. A subsequent analysis of published mtDNA control region sequences, which included sequences of extinct clades from other geographic regions, assigned the ancient Yakutian bear to the extinct clade 3c; a clade previously identified from Late Quaternary specimens from Eastern Beringia and Northern Spain. Our analyses of stable isotopes showed relatively high δ15N values in the Pleistocene Yakutian brown bears, suggesting a more carnivorous diet than contemporary brown bears from Eastern Beringia.

RevDate: 2019-03-13

Chyleński M, Ehler E, Somel M, et al (2019)

Ancient Mitochondrial Genomes Reveal the Absence of Maternal Kinship in the Burials of Çatalhöyük People and Their Genetic Affinities.

Genes, 10(3): pii:genes10030207.

Çatalhöyük is one of the most widely recognized and extensively researched Neolithic settlements. The site has been used to discuss a wide range of aspects associated with the spread of the Neolithic lifestyle and the social organization of Neolithic societies. Here, we address both topics using newly generated mitochondrial genomes, obtained by direct sequencing and capture-based enrichment of genomic libraries, for a group of individuals buried under a cluster of neighboring houses from the classical layer of the site's occupation. Our data suggests a lack of maternal kinship between individuals interred under the floors of Çatalhöyük buildings. The findings could potentially be explained either by a high variability of maternal lineages within a larger kin group, or alternatively, an intentional selection of individuals for burial based on factors other than biological kinship. Our population analyses shows that Neolithic Central Anatolian groups, including Çatalhöyük, share the closest affinity with the population from the Marmara Region and are, in contrast, set further apart from the Levantine populations. Our findings support the hypothesis about the emergence and the direction of spread of the Neolithic within Anatolian Peninsula and beyond, emphasizing a significant role of Central Anatolia in this process.

RevDate: 2019-03-08

van der Valk T, Vezzi F, Ormestad M, et al (2019)

Index hopping on the Illumina HiseqX platform and its consequences for ancient DNA studies.

Molecular ecology resources [Epub ahead of print].

The high-throughput capacities of the Illumina sequencing platforms and the possibility to label samples individually have encouraged a wide use of sample multiplexing. However, this practice results in read misassignment (usually <1%) across samples sequenced on the same lane. Alarmingly high rates of read misassignment of up to 10% were reported for lllumina sequencing machines with exclusion amplification chemistry. This may make use of these platforms prohibitive, particularly in studies that rely on low quantity and quality samples, such as historical and archaeological specimens. Here, we use barcodes, short sequences that are ligated to both ends of the DNA insert, to directly quantify the rate of index hopping in 100-year old museum-preserved gorilla (Gorilla beringei) samples. Correcting for multiple sources of noise, we identify on average 0.470% of reads containing a hopped index. We show that sample-specific quantity of misassigned reads depends on the number of reads that any given sample contributes to the total sequencing pool, so that samples with few sequenced reads receive the greatest proportion of misassigned reads. This particularly affects ancient DNA samples, as these frequently differ in their DNA quantity and endogenous content. Through simulations we show that even low rates of index hopping, as reported here, can lead to biases in ancient DNA studies when multiplexing samples with vastly different quantities of endogenous material. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-07

Pinhasi R, Fernandes DM, Sirak K, et al (2019)

Isolating the human cochlea to generate bone powder for ancient DNA analysis.

Nature protocols pii:10.1038/s41596-019-0137-7 [Epub ahead of print].

The cortical bone that forms the structure of the cochlea, part of the osseous labyrinth of the inner ear, is now one of the most frequently used skeletal elements in analyses of human ancient DNA. However, there is currently no published, standardized method for its sampling. This protocol describes the preparation of bone powder from the cochlea of fragmented skulls in which the petrous pyramid of the temporal bone is accessible. Using a systematic process of bone removal based on distinct anatomical landmarks and the identification of relevant morphological features, a petrous pyramid is cleaned with a sandblaster, and the cochlea is located, isolated, and reduced to a homogeneous bone powder. All steps are carried out in dedicated ancient DNA facilities, thus reducing the introduction of contamination. This protocol requires an understanding of ancient DNA clean-room procedures and basic knowledge of petrous pyramid anatomy. In 50-65 min, it results in bone powder with endogenous DNA yields that can exceed those from teeth and other bones by up to two orders of magnitude. Compared with drilling methods, this method facilitates a more precise targeting of the cochlea, allows the user to visually inspect the cochlea and remove any residual sediment before the generation of bone powder, and confines the damage to the inner ear region and surface of the petrous portion of fragmentary crania.

RevDate: 2019-03-04

Signore AV, Paijmans JLA, Hofreiter M, et al (2019)

Emergence of a chimeric globin pseudogene and increased hemoglobin oxygen affinity underlie the evolution of aquatic specializations in Sirenia.

Molecular biology and evolution pii:5369092 [Epub ahead of print].

As limits on O2 availability during submergence impose severe constraints on aerobic respiration, the oxygen binding globin proteins of marine mammals are expected to have evolved under strong evolutionary pressures during their land-to-sea transition. Here we address this question for the order Sirenia by retrieving, annotating, and performing detailed selection analyses on the globin repertoire of the extinct Steller's sea cow (Hydrodamalis gigas), dugong (Dugong dugon), and Florida manatee (Trichechus manatus latirostris) in relation to their closest living terrestrial relatives (elephants and hyraxes). These analyses indicate most loci experienced elevated nucleotide substitution rates during their transition to a fully aquatic lifestyle. While most of these genes evolved under neutrality or strong purifying selection, the rate of non-synonymous/synonymous replacements increased in two genes (Hbz-T1 and Hba-T1) that encode the α-type chains of hemoglobin (Hb) during each stage of life. Notably, the relaxed evolution of Hba-T1 is temporally coupled with the emergence of a chimeric pseudogene (Hba-T2/Hbq-ps) that contributed to the tandemly linked Hba-T1 of stem sirenians via interparalog gene conversion. Functional tests on recombinant Hb proteins from extant and ancestral sirenians further revealed that the molecular remodeling of Hba-T1 coincided with increased Hb-O2 affinity in early sirenians. Available evidence suggests this trait evolved to maximize O2 extraction from finite lung stores and suppress tissue O2 offloading, thereby facilitating the low metabolic intensities of extant sirenians. By contrast, the derived reduction in Hb-O2 affinity in (sub)Arctic Steller's sea cows is consistent with fueling increased thermogenesis by these once colossal marine herbivores.

RevDate: 2019-02-26

Ballard JWO, LAB Wilson (2019)

The Australian dingo: untamed or feral?.

Frontiers in zoology, 16:2 pii:300.

Background: The Australian dingo continues to cause debate amongst Aboriginal people, pastoralists, scientists and the government in Australia. A lingering controversy is whether the dingo has been tamed and has now reverted to its ancestral wild state or whether its ancestors were domesticated and it now resides on the continent as a feral dog. The goal of this article is to place the discussion onto a theoretical framework, highlight what is currently known about dingo origins and taxonomy and then make a series of experimentally testable organismal, cellular and biochemical predictions that we propose can focus future research.

Discussion: We consider a canid that has been unconsciously selected as a tamed animal and the endpoint of methodical or what we now call artificial selection as a domesticated animal. We consider wild animals that were formerly tamed as untamed and those wild animals that were formerly domesticated as feralized. Untamed canids are predicted to be marked by a signature of unconscious selection whereas feral animals are hypothesized to be marked by signatures of both unconscious and artificial selection. First, we review the movement of dingo ancestors into Australia. We then discuss how differences between taming and domestication may influence the organismal traits of skull morphometrics, brain and size, seasonal breeding, and sociability. Finally, we consider cellular and molecular level traits including hypotheses concerning the phylogenetic position of dingoes, metabolic genes that appear to be under positive selection and the potential for micronutrient compensation by the gut microbiome.

Conclusions: Western Australian Government policy is currently being revised to allow the widespread killing of the Australian dingo. These policies are based on an incomplete understanding of the evolutionary history of the canid and assume the dingo is feralized. However, accumulated evidence does not definitively show that the dingo was ever domesticated and additional focused research is required. We suggest that incorporating ancient DNA data into the debate concerning dingo origins will be pivotal to understanding the evolutionary history of the canid. Further, we advocate that future morphological, behavioural and genetic studies should focus on including genetically pure Alpine and Desert dingoes and not dingo-dog hybrids. Finally, we propose that future studies critically examine genes under selection in the dingo and employ the genome from a wild canid for comparison.

RevDate: 2019-02-26

Dick JM, Yu M, Tan J, et al (2019)

Changes in Carbon Oxidation State of Metagenomes Along Geochemical Redox Gradients.

Frontiers in microbiology, 10:120.

There is widespread interest in how geochemistry affects the genomic makeup of microbial communities, but the possible impacts of oxidation-reduction (redox) conditions on the chemical composition of biomacromolecules remain largely unexplored. Here we document systematic changes in the carbon oxidation state, a metric derived from the chemical formulas of biomacromolecular sequences, using published metagenomic and metatranscriptomic datasets from 18 studies representing different marine and terrestrial environments. We find that the carbon oxidation states of DNA, as well as proteins inferred from coding sequences, follow geochemical redox gradients associated with mixing and cooling of hot spring fluids in Yellowstone National Park (USA) and submarine hydrothermal fluids. Thermodynamic calculations provide independent predictions for the environmental shaping of the gene and protein composition of microbial communities in these systems. On the other hand, the carbon oxidation state of DNA is negatively correlated with oxygen concentration in marine oxygen minimum zones. In this case, a thermodynamic model is not viable, but the low carbon oxidation state of DNA near the ocean surface reflects a low GC content, which can be attributed to genome reduction in organisms adapted to low-nutrient conditions. We also present evidence for a depth-dependent increase of oxidation state at the species level, which might be associated with alteration of DNA through horizontal gene transfer and/or selective degradation of relatively reduced (AT-rich) extracellular DNA by heterotrophic bacteria. Sediments exhibit even more complex behavior, where carbon oxidation state minimizes near the sulfate-methane transition zone and rises again at depth; markedly higher oxidation states are also associated with older freshwater-dominated sediments in the Baltic Sea that are enriched in iron oxides and have low organic carbon. This geobiochemical study of carbon oxidation state reveals a new aspect of environmental information in metagenomic sequences, and provides a reference frame for future studies that may use ancient DNA sequences as a paleoredox indicator.

RevDate: 2019-02-24

Mao Y, N Satoh (2019)

A Likely Ancient Genome Duplication in the Speciose Reef-Building Coral Genus, Acropora.

iScience, 13:20-32 pii:S2589-0042(19)30035-5 [Epub ahead of print].

Whole-genome duplication (WGD) has been recognized as a significant evolutionary force in the origin and diversification of multiple organisms. Acropora, a speciose reef-building coral genus, is suspected to have originated by polyploidy. Yet, there is no genetic evidence to support this hypothesis. Using comprehensive phylogenomic and comparative genomic approaches, we analyzed six Acroporid genomes and found that a WGD event likely occurred ∼31 million years ago in the most recent common ancestor of Acropora, concurrent with a worldwide coral extinction. We found that duplicated genes were highly enriched in gene regulation functions, including those of stress responses. The functional clusters of duplicated genes are related to the divergence of gene expression patterns during development. Some proteinaceous toxins were generated by WGD in Acropora compared with other cnidarian species. Collectively, this study provides evidence for an ancient WGD event in corals, which helps explain the origin and diversification of Acropora.

RevDate: 2019-02-22

Shaw JLA, Weyrich LS, Hallegraeff G, et al (2019)

Retrospective eDNA assessment of potentially harmful algae in historical ship ballast tank and marine port sediments.

Molecular ecology [Epub ahead of print].

Microalgal bloom events can cause major ecosystem disturbances, devastate local marine economies, and endanger public health. Therefore, detecting and monitoring harmful microalgal taxa is essential to ensure effective risk management in waterways used for fisheries, aquaculture, recreational activity, and shipping. To fully understand the current status and future direction of algal bloom distributions, we need to know how populations and ecosystems have changed over time. This baseline knowledge is critical for predicting ecosystem responses to future anthropogenic change and will assist in the future management of coastal ecosystems. We explore a NGS metabarcoding approach to rapidly identify potentially harmful microalgal taxa in 63 historic and modern Australian marine port and ballast tank sediment samples. The results provide a record of past microalgal distribution and important baseline data that can be used to assess the efficacy of shipping guidelines, nutrient pollution mitigation, and predict the impact of climate change. Critically, eDNA surveys of archived sediments were able to detect harmful algal taxa that do not produce microscopic fossils, such as Chattonella, Heterosigma, Karlodinium, and Noctiluca. Our data suggest a potential increase in Australian harmful microalgal taxa over the past 30 years, and confirm ship ballast tanks as key dispersal vectors. These molecular mapping tools will assist in the creation of policies aimed at reducing the global increase and spread of harmful algal taxa and help prevent economic and public-health problems caused by harmful algal blooms. This article is protected by copyright. All rights reserved.

RevDate: 2019-02-18

Grealy A, Bunce M, C Holleley (2019)

Avian mitochondrial genomes retrieved from museum eggshell.

Molecular ecology resources [Epub ahead of print].

Avian eggshell is a bio-ceramic material with exceptional properties for preserving DNA within its crystalline structure, presenting an opportunity to retrieve genomic information from extinct or historic populations of birds. However, intracrystalline DNA has only been recovered from the large, thick eggshell of palaeognaths; members of their more-diverse sister group (neognaths) lay smaller, thinner eggs that may not exhibit the same propensity for DNA preservation. Here, we use three 40-60 year-old museum eggshell specimens of Australian neognath birds to determine the minimum mass of eggshell from which intracrystalline DNA can be retrieved, and to characterise the yield and quality of such DNA. In doing so, we describe the first protocol for successful extraction of intractrystalline DNA from neognath eggshells, with the view to unlocking the potential of vast museum egg collections for genetic research. We were able to retrieve DNA fragments over 200 bp in length from 10 mg of eggshell powder from all three specimens, and demonstrate that expanding the existing blow-hole can allow sufficient material to be collected for DNA extraction while minimising damage to the appearance and structural integrity of the egg. Furthermore, we were able to reconstruct near-complete mitochondrial genomes at a coverage of 40-83X through shotgun sequencing of these extracts on three NextSeq lanes. Given the current extinction and extirpation rates of many avian species world-wide, genetic data from eggshell could provide a rapid and cost-effective approach to examining temporal changes in avian diversity, which is not only becoming crucial for conservation management, but also serve to deepen our understanding of genome-wide evolutionary processes. This article is protected by copyright. All rights reserved.

RevDate: 2019-02-12

Knapp M, Thomas JE, Haile J, et al (2019)

Mitogenomic evidence of close relationships between New Zealand's extinct giant raptors and small-sized Australian sister-taxa.

Molecular phylogenetics and evolution pii:S1055-7903(18)30632-8 [Epub ahead of print].

Prior to human arrival in the 13th century, two large birds of prey were the top predators in New Zealand. In the absence of non-volant mammals, the extinct Haast's eagle (Hieraaetus moorei), the largest eagle in the world, and the extinct Eyles' harrier (Circus teauteensis) the largest harrier in the world, had filled ecological niches that are on other landmasses occupied by animals such as large cats or canines. The evolutionary and biogeographic history of these island giants has long been a mystery. Here we reconstruct the origin and evolution of New Zealand's giant raptors using complete mitochondrial genome data. We show that both Eyles' harrier and Haast's eagle diverged from much smaller, open land adapted Australasian relatives in the late Pliocene to early Pleistocene. These events coincided with the development of open habitat in the previously densely forested islands of New Zealand. Our study provides evidence of rapid evolution of island gigantism in New Zealand's extinct birds of prey. Early Pleistocene climate and environmental changes were likely to have triggered the establishment of Australian raptors into New Zealand. Our results shed light on the evolution of two of the most impressive cases of island gigantism in the world.

RevDate: 2019-02-12

Pont C, Wagner S, Kremer A, et al (2019)

Paleogenomics: reconstruction of plant evolutionary trajectories from modern and ancient DNA.

Genome biology, 20(1):29 pii:10.1186/s13059-019-1627-1.

How contemporary plant genomes originated and evolved is a fascinating question. One approach uses reference genomes from extant species to reconstruct the sequence and structure of their common ancestors over deep timescales. A second approach focuses on the direct identification of genomic changes at a shorter timescale by sequencing ancient DNA preserved in subfossil remains. Merged within the nascent field of paleogenomics, these complementary approaches provide insights into the evolutionary forces that shaped the organization and regulation of modern genomes and open novel perspectives in fostering genetic gain in breeding programs and establishing tools to predict future population changes in response to anthropogenic pressure and global warming.

RevDate: 2019-02-11

Tennant RK, Lux TM, Sambles CM, et al (2019)

Palaeogenomics of the Hydrocarbon Producing Microalga Botryococcus braunii.

Scientific reports, 9(1):1776 pii:10.1038/s41598-018-38236-5.

Botryococcus braunii is a colonial microalga that appears early in the fossil record and is a sensitive proxy of environmental and hydroclimatic conditions. Palaeozoic Botryococcus fossils which contribute up to 90% of oil shales and approximately 1% of crude oil, co-localise with diagnostic geolipids from the degradation of source-signature hydrocarbons. However more recent Holocene sediments demonstrate no such association. Consequently, Botryococcus are identified in younger sediments by morphology alone, where potential misclassifications could lead to inaccurate paleoenvironmental reconstructions. Here we show that a combination of flow cytometry and ancient DNA (aDNA) sequencing can unambiguously identify Botryococcus microfossils in Holocene sediments with hitherto unparalleled accuracy and rapidity. The application of aDNA sequencing to microfossils offers a far-reaching opportunity for understanding environmental change in the recent geological record. When allied with other high-resolution palaeoenvironmental information such as aDNA sequencing of humans and megafauna, aDNA from microfossils may allow a deeper and more precise understanding of past environments, ecologies and migrations.

RevDate: 2019-02-07

Gross M (2017)

Roots of Mediterranean civilisations.

Current biology : CB, 27(18):R979-R982.

European culture traces its history back to the ancient Greek civilisations, while Christianity and Judaism have their roots in the populations on the eastern shore of the Mediterranean Sea. Genome studies of several Bronze Age individuals from each of these regions have now probed the genetic roots of early civilisations, revealing both migration and continuity in both cases. Michael Gross reports.

RevDate: 2019-02-06

Gomez Cabrera MDC, Young JM, Roff G, et al (2019)

Broadening the taxonomic scope of coral reef paleoecological studies using ancient DNA.

Molecular ecology [Epub ahead of print].

Marine environments face acute pressures from human impacts, often resulting in substantial changes in community structure. On the inshore Great Barrier Reef (GBR), paleoecological studies show the collapse of the previously dominant coral Acropora from the impacts of degraded water quality associated with European colonization. Even more dramatic impacts can result in the replacement of corals by fleshy macroalgae on modern reefs, but their past distribution is unknown because they leave no fossil record. Here we apply DNA metabarcoding and High-Throughput Sequencing of the 18S rDNA gene on paleoenvironmental DNA (aeDNA) derived from sediment cores at two sites on Pandora Reef (GBR), to enhance paleoecological studies by incorporating key soft-bodied taxa, including macroalgae. We compared temporal trends in this aeDNA record with those of coral genera derived from macrofossils. Multivariate analysis of 12 eukaryotic groups from the aeDNA community showed wide variability over the past 750 years. The occurrence of brown macroalgae was negatively correlated only with the dominant coral at both sites. The occurrence of coralline and green macroalgae was positively correlated with only the dominant coral at one of the sites, where we also observed a significant association between the whole coral community and the occurrence of each of the 3 macroalgae groups. Our results demonstrate that reef sediments can provide a valuable archive for understanding the past distribution and occurrence of important soft-bodied reef dwellers. Combining information from fossils and aeDNA provides an enhanced understanding of temporal changes of reefs ecosystems at decadal to millennial time-scales. This article is protected by copyright. All rights reserved.

RevDate: 2019-02-05

Cole TL, Ksepka DT, Mitchell KJ, et al (2019)

Mitogenomes uncover extinct penguin taxa and reveal island formation as a key driver of speciation.

Molecular biology and evolution pii:5303836 [Epub ahead of print].

The emergence of islands has been linked to spectacular radiations of diverse organisms. Although penguins spend much of their lives at sea, they rely on land for nesting, and a high proportion of extant species are endemic to geologically-young islands. Islands may thus have been crucial to the evolutionary diversification of penguins. We test this hypothesis using a fossil-calibrated phylogeny of mitochondrial genomes (mitogenomes) from all extant and recently extinct penguin taxa. Our temporal analysis demonstrates that numerous recent island-endemic penguin taxa diverged following the formation of their islands during the Plio-Pleistocene, including the Galápagos (Galápagos Islands), northern rockhopper (Gough Island), erect-crested (Antipodes Islands), Snares crested (Snares) and royal (Macquarie Island) penguins. Our analysis also reveals two new recently extinct island-endemic penguin taxa from New Zealand's Chatham Islands: Eudyptes warhami sp. nov. and a dwarf subspecies of the yellow-eyed penguin, Megadyptes antipodes richdalei ssp. nov. Eudyptes warhami diverged from the Antipodes Islands erect-crested penguin between 1.1 million years ago (Ma) and 2.5 Ma, shortly after the emergence of the Chatham Islands (∼3 Ma). This new finding of recently-evolved taxa on this young archipelago provides further evidence that the radiation of penguins over the last 5 Ma has been linked to island emergence. Mitogenomic analyses of all penguin species, and the discovery of two new extinct penguin taxa, highlight the importance of island formation in the diversification of penguins, as well as the extent to which anthropogenic extinctions have affected island-endemic taxa across the Southern Hemisphere's isolated archipelagos.

RevDate: 2019-02-04

Richards SM, Hovhannisyan N, Gilliham M, et al (2019)

Low-cost cross-taxon enrichment of mitochondrial DNA using in-house synthesised RNA probes.

PloS one, 14(2):e0209499 pii:PONE-D-18-24048.

Hybridization capture with in-solution oligonucleotide probes has quickly become the preferred method for enriching specific DNA loci from degraded or ancient samples prior to high-throughput sequencing (HTS). Several companies synthesize sets of probes for in-solution hybridization capture, but these commercial reagents are usually expensive. Methods for economical in-house probe synthesis have been described, but they do not directly address one of the major advantages of commercially synthesised probes: that probe sequences matching many species can be synthesised in parallel and pooled. The ability to make "phylogenetically diverse" probes increases the cost-effectiveness of commercial probe sets, as they can be used across multiple projects (or for projects involving multiple species). However, it is labour-intensive to replicate this with in-house methods, as template molecules must first be generated for each species of interest. While it has been observed that probes can be used to enrich for phylogenetically distant targets, the ability of this effect to compensate for the lack of phylogenetically diverse probes in in-house synthesised probe sets has not been tested. In this study, we present a refined protocol for in-house RNA probe synthesis and evaluated the ability of probes generated using this method from a single species to successfully enrich for the target locus in phylogenetically distant species. We demonstrated that probes synthesized using long-range PCR products from a placental mammal mitochondrion (Bison spp.) could be used to enrich for mitochondrial DNA in birds and marsupials (but not plants). Importantly, our results were obtained for approximately a third of the cost of similar commercially available reagents.

RevDate: 2019-02-04

Costedoat C, Adalian P, Bouzaid E, et al (2019)

When a lost "Petit Prince" meets Antoine de Saint Exupéry: An anthropological case report.

Forensic science international pii:S0379-0738(19)30024-6 [Epub ahead of print].

This case study reports the anthropological analysis of bones remains discovered on Riou Island (Marseille, France) and the story of two World War II fighter pilots. The discovery of bones on "The Fountain of the Greeks" square on Riou Island occurred in the 1960's and a first anthropological study described a 35-year-old man, about 1.77 m tall, buried since an estimated period between the 13th and 16th centuries. The case was "closed" and the bones were considered as isolated archaeological remains. Few years later, near the coasts of Riou Island, parts of two planes were discovered. One was from of a German Messerschmitt Bf 109 F-4 of the Luftwaffe piloted by Prince Alexis fürst zu Bentheim und Steinfurt, and the other from a French P-38 Lightning F-5 B piloted by Antoine de Saint-Exupery. Therefore, the identification of the skeletal remains mentioned above was then thought to be perhaps one of the two World War II pilots. In this particular context we performed forensic and molecular biology analyses to resolve this identification.

RevDate: 2019-02-01

Díaz FP, Latorre C, Carrasco-Puga G, et al (2019)

Multiscale climate change impacts on plant diversity in the Atacama Desert.

Global change biology [Epub ahead of print].

Comprehending ecological dynamics requires not only knowledge of modern communities but also detailed reconstructions of ecosystem history. Ancient DNA (aDNA) metabarcoding allows biodiversity responses to major climatic change to be explored at different spatial and temporal scales. We extracted aDNA preserved in fossil rodent middens to reconstruct late Quaternary vegetation dynamics in the hyperarid Atacama Desert. By comparing our paleo-informed millennial record with contemporary observations of interannual variations in diversity, we show local plant communities behave differentially at different timescales. In the inter-annual (years to decades) time frame, only annual herbaceous expand and contract their distributional ranges (emerging from persistent seed banks) in response to precipitation, whereas perennials distribution appear to be extraordinarily resilient. In contrast, at longer time scales (thousands of years) many perennial species were displaced up to 1,000 m downslope during pluvial events. Given ongoing and future natural and anthropogenically-induced climate change, our results not only provide baselines for vegetation in the Atacama Desert, but also help to inform how these and other high mountain plant communities may respond to fluctuations of climate in the future. This article is protected by copyright. All rights reserved.

RevDate: 2019-01-31

Rusu I, Modi A, Radu C, et al (2019)

Mitochondrial ancestry of medieval individuals carelessly interred in a multiple burial from southeastern Romania.

Scientific reports, 9(1):961 pii:10.1038/s41598-018-37760-8.

The historical province of Dobruja, located in southeastern Romania, has experienced intense human population movement, invasions, and conflictual episodes during the Middle Ages, being an important intersection point between Asia and Europe. The most informative source of maternal population histories is the complete mitochondrial genome of archaeological specimens, but currently, there is insufficient ancient DNA data available for the medieval period in this geographical region to complement the archaeological findings. In this study, we reconstructed, by using Next Generation Sequencing, the entire mitochondrial genomes (mitogenomes) of six medieval individuals neglectfully buried in a multiple burial from Capidava necropolis (Dobruja), some presenting signs of a violent death. Six distinct maternal lineages (H11a1, U4d2, J1c15, U6a1a1, T2b, and N1a3a) with different phylogenetic background were identified, pointing out the heterogeneous genetic aspect of the analyzed medieval group. Using population genetic analysis based on high-resolution mitochondrial data, we inferred the genetic affinities of the available medieval dataset from Capidava to other ancient Eurasian populations. The genetic data were integrated with the archaeological and anthropological information in order to sketch a small, local piece of the mosaic that is the image of medieval European population history.

RevDate: 2019-01-29

Cilli E, Sarno S, Gnecchi Ruscone GA, et al (2019)

The genetic legacy of the Yaghnobis: A witness of an ancient Eurasian ancestry in the historically reshuffled central Asian gene pool.

American journal of physical anthropology [Epub ahead of print].

OBJECTIVES: The Yaghnobis are an ethno-linguistic minority historically settled along the Yaghnob River in the Upper-Zarafshan Valley in Tajikistan. They speak a language of Old Sogdian origin, which is the only present-day witness of the Lingua Franca used along the Silk Road in Late Antiquity. The aim of this study was to reconstruct the genetic history of this community in order to shed light on its isolation and genetic ancestry within the Euro-Asiatic context.

MATERIALS AND METHODS: A total of 100 DNA samples were collected in the Yaghnob and Matcha Valleys during several expeditions and their mitochondrial, Y-chromosome and autosomal genome-wide variation were compared with that from a large set of modern and ancient Euro-Asiatic samples.

RESULTS: Findings from uniparental markers highlighted the long-term isolation of the Yaghnobis. Mitochondrial DNA ancestry traced an ancient link with Middle Eastern populations, whereas Y-chromosome legacy showed more tight relationships with Central Asians. Admixture, outgroup-f3, and D-statistics computed on autosomal variation corroborated Y-chromosome evidence, pointing respectively to low Anatolian Neolithic and high Steppe ancestry proportions in Yaghnobis, and to their closer affinity with Tajiks than to Iranians.

DISCUSSION: Although the Yaghnobis do not show evident signs of recent admixture, they could be considered a modern proxy for the source of gene flow for many Central Asian and Middle Eastern groups. Accordingly, they seem to retain a peculiar genomic ancestry probably ascribable to an ancient gene pool originally wide spread across a vast area and subsequently reshuffled by distinct demographic events occurred in Middle East and Central Asia.

RevDate: 2019-01-25

Slepchenko SM, Gusev AV, Svyatova EO, et al (2019)

Medieval mummies of Zeleny Yar burial ground in the Arctic Zone of Western Siberia.

PloS one, 14(1):e0210718 pii:PONE-D-18-17918.

Notwithstanding the pioneering achievements of studies on arctic mummies in Siberia, there are insufficient data for any comprehensive understanding of the bio-cultural details of medieval people living in the region. In the Western Siberian arctic, permafrost mummies have been found in 12th to 13th century graves located in the Zeleny Yar (Z-Y) burial ground (66°19'4.54"С; 67°21'13.54"В). In 2013-2016, we were fortunate to be able to excavate that cemetery, locating a total of 47 burials, including cases of mummification. Some of these mummies had been wrapped in a multi-layered birch-bark cocoon. After removal of the cocoon, we conducted interdisciplinary studies using various scientific techniques. Gross anatomical examination and CT radiography showed that the internal organs were still well preserved inside the body cavities. Under light and electron microscopy, the histological findings were very similar to those for naturally mummified specimens discovered in other countries. Ancient DNA analysis showed that the Z-Y mummies' mtDNA haplotypes belong to five different haplogroups, namely U5a (#34), H3ao (#53), D (#67-1), U4b1b1 (#67-2), and D4j8 (#68), which distinguish them for their unique combination of Western- and Eastern Siberia-specific mtDNA haplogroups. Our interdisciplinary study obtained fundamental information that will form the foundation of successful future investigations on medieval mummies found in the Western Siberian arctic.

RevDate: 2019-01-14
CmpDate: 2019-01-14

Gibbons A (2018)

Why modern humans have round heads.

Science (New York, N.Y.), 362(6420):1229.

RevDate: 2019-01-11

O'Connor TD (2019)

Native American Genomic Diversity through Ancient DNA.

Cell, 176(1-2):405-406.

RevDate: 2019-01-11
CmpDate: 2019-01-11

Matsumura H, Shinoda KI, Shimanjuntak T, et al (2018)

Cranio-morphometric and aDNA corroboration of the Austronesian dispersal model in ancient Island Southeast Asia: Support from Gua Harimau, Indonesia.

PloS one, 13(6):e0198689.

The Austronesian language is spread from Madagascar in the west, Island Southeast Asia (ISEA) in the east (e.g. the Philippines and Indonesian archipelagoes) and throughout the Pacific, as far east as Easter Island. While it seems clear that the remote ancestors of Austronesian speakers originated in Southern China, and migrated to Taiwan with the development of rice farming by c. 5500 BP and onto the northern Philippines by c. 4000 BP (the Austronesian Dispersal Hypothesis or ADH), we know very little about the origins and emergence of Austronesian speakers in the Indonesian Archipelago. Using a combination of cranial morphometric and ancient mtDNA analyses on a new dataset from Gua Hairmau, that spans the pre-Neolithic through to Metal Period (5712-5591cal BP to 1864-1719 cal BP), we rigorously test the validity of the ADH in ISEA. A morphometric analysis of 23 adult male crania, using 16 of Martin's standard measurements, was carried out with results compared to an East and Southeast Asian dataset of 30 sample populations spanning the Late Pleistocene through to Metal Period, in addition to 39 modern samples from East and Southeast Asia, near Oceania and Australia. Further, 20 samples were analyzed for ancient mtDNA and assigned to identified haplogroups. We demonstrate that the archaeological human remains from Gua Harimau cave, Sumatra, Indonesia provide clear evidence for at least two (cranio-morphometrically defined) and perhaps even three (in the context of the ancient mtDNA results) distinct populations from two separate time periods. The results of these analyses provide substantive support for the ADH model in explaining the origins and population history of ISEA peoples.

RevDate: 2019-01-10

Tackney J, Jensen AM, Kisielinski C, et al (2019)

Molecular analysis of an ancient Thule population at Nuvuk, Point Barrow, Alaska.

American journal of physical anthropology, 168(2):303-317.

OBJECTIVES: The North American archaeological record supports a Holocene origin of Arctic Indigenous peoples. Although the Paleo-Inuit were present for millennia, archaeological and genetic studies suggest that modern peoples descend from a second, more recent tradition known as the Neo-Inuit. Origins of the Neo-Inuit and their relations to the earlier and later Indigenous peoples are an area of active study. Here, we genetically analyze the maternal lineages present at Nuvuk, once the northernmost community in Alaska and located in a region identified as a possible origin point of the Neo-Inuit Thule. The cemetery at Nuvuk contains human remains representing a nearly one thousand year uninterrupted occupation from early Thule to post-contact Iñupiat.

MATERIALS AND METHODS: We selected 44 individuals from Nuvuk with calibrated dates between 981 AD and 1885 AD for molecular analysis. We amplified and sequenced the hypervariable segment I of the mitogenome. We compared the Nuvuk data with previously published sequences from 68 modern and ancient communities from across Asia and North America. Phylogeographic analyses suggest possible scenarios of Holocene Arctic and sub-Arctic population movements.

RESULTS: We successfully retrieved sequence data from 39 individuals. Haplogroup frequencies in Nuvuk were typed as 66.7% A2b1, 25.6% A2a, and 7.7% D4b1a2a1a. These results suggest that the population at Nuvuk was closest to the ancient Thule and modern Inuit of Canada, and to the Siberian Naukan people. We confirm that haplogroups A2a, A2b1, D2a, and D4b1a2a1a appear at high frequency in Arctic and sub-Arctic populations of North America and Chukotka. Sister clades D2b and D4b1a2a1b are present in Asian and Eastern European populations.

DISCUSSION: The ancient mitochondrial sequences from Nuvuk confirm the link between the North Slope and the Thule who later spread east, and the maternal discontinuity between the Neo-Inuit and Paleo-Inuit. We suggest haplogroups A2a, A2b, and D4b1a2a1a are linked to the ancestors of the Thule in eastern Beringia, whereas the D2 and D4b1a2a1 clades appear to have Asian Holocene origins. Further Siberian and Alaskan genomes are necessary to clarify these population migrations beyond a simple two-wave scenario of Neo-Inuit and Paleo-Inuit.

RevDate: 2019-01-09

Wales N, Akman M, Watson RHB, et al (2019)

Ancient DNA reveals the timing and persistence of organellar genetic bottlenecks over 3,000 years of sunflower domestication and improvement.

Evolutionary applications, 12(1):38-53 pii:EVA12594.

Here, we report a comprehensive paleogenomic study of archaeological and ethnographic sunflower remains that provides significant new insights into the process of domestication of this important crop. DNA from both ancient and historic contexts yielded high proportions of endogenous DNA, and although archaeological DNA was found to be highly degraded, it still provided sufficient coverage to analyze genetic changes over time. Shotgun sequencing data from specimens from the Eden's Bluff archaeological site in Arkansas yielded organellar DNA sequence from specimens up to 3,100 years old. Their sequences match those of modern cultivated sunflowers and are consistent with an early domestication bottleneck in this species. Our findings also suggest that recent breeding of sunflowers has led to a loss of genetic diversity that was present only a century ago in Native American landraces. These breeding episodes also left a profound signature on the mitochondrial and plastid haplotypes in cultivars, as two types were intentionally introduced from other Helianthus species for crop improvement. These findings gained from ancient and historic sunflower specimens underscore how future in-depth gene-based analyses can advance our understanding of the pace and targets of selection during the domestication of sunflower and other crop species.

RevDate: 2019-01-07

Harris AJT, Duggan AT, Marciniak S, et al (2019)

Dorset Pre-Inuit and Beothuk foodways in Newfoundland, ca. AD 500-1829.

PloS one, 14(1):e0210187 pii:PONE-D-18-20300.

Archaeological research on the Canadian island of Newfoundland increasingly demonstrates that the island's subarctic climate and paucity of terrestrial food resources did not restrict past Pre-Inuit (Dorset) and Native American (Beothuk) hunter-gatherer populations to a single subsistence pattern. This study first sought to characterize hunter-gatherer diets over the past 1500 years; and second, to assess the impact of European colonization on Beothuk lifeways by comparing the bone chemistry of Beothuk skeletal remains before and after the intensification of European settlement in the early 18th century. We employed radiocarbon dating and stable carbon and nitrogen isotope ratio analysis of bulk bone collagen from both Dorset (n = 9) and Beothuk (n = 13) cultures, including a naturally mummified 17th century Beothuk individual. Carbon and nitrogen isotope analysis of 108 faunal samples from Dorset and Beothuk archaeological sites around the island were used as a dietary baseline for the humans. We combined our results with previously published isotope data and radiocarbon dates from Dorset (n = 12) and Beothuk (n = 18) individuals and conducted a palaeodietary analysis using Bayesian modelling, cluster analysis and comparative statistical tests. Dorset diets featured more marine protein than those of the Beothuk, and the diets of Beothuk after the 18th century featured less high trophic level marine protein than those of individuals predating the 18th century. Despite inhabiting the same island, Dorset and Beothuk cultures employed markedly different dietary strategies, consistent with interpretations of other archaeological data. Significantly, European colonization had a profound effect on Beothuk lifeways, as in response to the increasing European presence on the coast, the Beothuk relied more extensively on the limited resources of the island's boreal forests and rivers.

RevDate: 2018-12-26

Ziesemer KA, Ramos-Madrigal J, Mann AE, et al (2018)

The efficacy of whole human genome capture on ancient dental calculus and dentin.

American journal of physical anthropology [Epub ahead of print].

OBJECTIVES: Dental calculus is among the richest known sources of ancient DNA in the archaeological record. Although most DNA within calculus is microbial, it has been shown to contain sufficient human DNA for the targeted retrieval of whole mitochondrial genomes. Here, we explore whether calculus is also a viable substrate for whole human genome recovery using targeted enrichment techniques.

MATERIALS AND METHODS: Total DNA extracted from 24 paired archaeological human dentin and calculus samples was subjected to whole human genome enrichment using in-solution hybridization capture and high-throughput sequencing.

RESULTS: Total DNA from calculus exceeded that of dentin in all cases, and although the proportion of human DNA was generally lower in calculus, the absolute human DNA content of calculus and dentin was not significantly different. Whole genome enrichment resulted in up to four-fold enrichment of the human endogenous DNA content for both dentin and dental calculus libraries, albeit with some loss in complexity. Recovering more on-target reads for the same sequencing effort generally improved the quality of downstream analyses, such as sex and ancestry estimation. For nonhuman DNA, comparison of phylum-level microbial community structure revealed few differences between precapture and postcapture libraries, indicating that off-target sequences in human genome-enriched calculus libraries may still be useful for oral microbiome reconstruction.

DISCUSSION: While ancient human dental calculus does contain endogenous human DNA sequences, their relative proportion is low when compared with other skeletal tissues. Whole genome enrichment can help increase the proportion of recovered human reads, but in this instance enrichment efficiency was relatively low when compared with other forms of capture. We conclude that further optimization is necessary before the method can be routinely applied to archaeological samples.

RevDate: 2018-12-24

Aguiar TS, Torrecilha RBP, Milanesi M, et al (2018)

Association of Copy Number Variation at Intron 3 of HMGA2 With Navel Length in Bos indicus.

Frontiers in genetics, 9:627.

Navel injuries caused by friction against the pasture can promote infection, reproductive problems and costly treatments in beef cattle raised in extensive systems. A haplotype-based genome-wide association study (GWAS) was performed for visual scores of navel length at yearling in Nellore cattle (Bos indicus) using data from 2,016 animals and 503,088 single nucleotide polymorphism (SNP) markers. The strongest signal (p = 1.01 × 10-9) was found on chromosome 5 spanning positions 47.9-48.2 Mbp. This region contains introns 3 and 4 and exons 4 and 5 of the high mobility group AT-hook 2 gene (HMGA2). Further inspection of the region with whole genome sequence data of 21 Nellore bulls revealed correlations between counts of the significant haplotype and copy number gains of a ∼6.2 kbp segment of intron 3 of HMGA2. Analysis of genome sequences from five African B. indicus and four European Bos taurus breeds revealed that the copy number variant (CNV) is indicine-specific. This intronic CNV was then validated through quantitative polymerase chain reaction (qPCR) using Angus animals as copy neutral controls. Importantly, the CNV was not detectable by means of conventional SNP-based GWAS or SNP probe intensity analyses. Given that HMGA2 affects the expression of the insulin-like growth factor 2 gene (IGF2) together with the pleomorphic adenoma gene 1 (PLAG1), and that the latter has been repeatedly shown to be associated with quantitative traits of economic importance in cattle, these findings highlight the emerging role of variants impacting the insulin-like growth factor pathway to cattle breeding.

RevDate: 2018-12-18

Varano S, Gaspari L, De Angelis F, et al (2018)

Mitochondrial characterisation of two Spanish populations from the Vera and Bejar valleys (Central Spain).

Annals of human biology [Epub ahead of print].

This survey reports the mitochondrial data of two Spanish populations living in the Vera and Bejar valleys, on the opposite slopes of the Sierra de Gredos (Central Spain), which crosses Spain east to west. The aim of the study was to characterise the mitochondrial genetic pool of the Vera and Bejar populations to investigate a putative mitogenetic differentiation between them, evidence that would support the role of the Sierra de Gredos as a genetic barrier in their micro-evolutionary histories. Blood samples of 137 people (66 from Vera and 71 from Bejar) were collected and mtDNA hypervariable regions I and II (HVR-I and HVR-II) were dissected along with several mtDNA- coding region SNPs. The main European mitochondrial lineages have been found both in Vera and in Bejar, together with the typical African haplogroups L (in Vera) and U6 (in Bejar). FST value and the 95% credible regions calculated for haplogroup frequencies do not reveal genetic differentiation among the populations. In conclusion, Vera and Bejar contain an expected mitochondrial variability within them, but they do not seem to be genetically different from each other, leading us to conclude that the Sierra de Gredos is not a significant genetic barrier in their maternal genetic history.

RevDate: 2018-12-17

Afonso C, Nociarova D, Santos C, et al (2018)

Sex selection in late Iberian infant burials: Integrating evidence from morphological and genetic data.

American journal of human biology : the official journal of the Human Biology Council [Epub ahead of print].

OBJECTIVE: The aim of this study was to analyze the infant burials found inside Iberian homes in relation to a possible case of sex selection.

METHODS: The study included the remains of 11 infant individuals buried under the 10 houses excavated in the late Iberian village of Camp de les Lloses (Tona, Barcelona, Spain). Sex was determined using genetic analysis.

RESULTS: Our results showed that almost all the burials were females. However, the age interval of death was wide enough to weaken the premise of infanticide, and the burials probably represent cases of natural death.

DISCUSSION: Infanticide in its different forms has long been argued as an explanation for the infant remains found throughout various burial sites. Many authors thought that infanticide, mainly femicide, was the main method of population control in ancient times. However, there is no anthropological evidence (age distribution and sex analyzed genetically) to support the intentional killing of females in this or in other cases. We hypothesized that there was a positive selection for females to be buried inside the houses, probably related to their benefactor roles.

RevDate: 2018-12-17

Mohni KN, Wessel SR, Zhao R, et al (2018)

HMCES Maintains Genome Integrity by Shielding Abasic Sites in Single-Strand DNA.

Cell pii:S0092-8674(18)31454-5 [Epub ahead of print].

Abasic sites are one of the most common DNA lesions. All known abasic site repair mechanisms operate only when the damage is in double-stranded DNA. Here, we report the discovery of 5-hydroxymethylcytosine (5hmC) binding, ESC-specific (HMCES) as a sensor of abasic sites in single-stranded DNA. HMCES acts at replication forks, binds PCNA and single-stranded DNA, and generates a DNA-protein crosslink to shield abasic sites from error-prone processing. This unusual HMCES DNA-protein crosslink intermediate is resolved by proteasome-mediated degradation. Acting as a suicide enzyme, HMCES prevents translesion DNA synthesis and the action of endonucleases that would otherwise generate mutations and double-strand breaks. HMCES is evolutionarily conserved in all domains of life, and its biochemical properties are shared with its E. coli ortholog. Thus, HMCES is an ancient DNA lesion recognition protein that preserves genome integrity by promoting error-free repair of abasic sites in single-stranded DNA.

RevDate: 2018-12-17
CmpDate: 2018-12-17

Spyrou MA, Tukhbatova RI, Wang CC, et al (2018)

Analysis of 3800-year-old Yersinia pestis genomes suggests Bronze Age origin for bubonic plague.

Nature communications, 9(1):2234.

The origin of Yersinia pestis and the early stages of its evolution are fundamental subjects of investigation given its high virulence and mortality that resulted from past pandemics. Although the earliest evidence of Y. pestis infections in humans has been identified in Late Neolithic/Bronze Age Eurasia (LNBA 5000-3500y BP), these strains lack key genetic components required for flea adaptation, thus making their mode of transmission and disease presentation in humans unclear. Here, we reconstruct ancient Y. pestis genomes from individuals associated with the Late Bronze Age period (~3800 BP) in the Samara region of modern-day Russia. We show clear distinctions between our new strains and the LNBA lineage, and suggest that the full ability for flea-mediated transmission causing bubonic plague evolved more than 1000 years earlier than previously suggested. Finally, we propose that several Y. pestis lineages were established during the Bronze Age, some of which persist to the present day.

RevDate: 2018-12-14

Winters M, Monroe C, Barta JL, et al (2018)

Evaluating the Efficiency of Primer Extension Capture as a Method to Enrich DNA Extractions.

Journal of forensic sciences [Epub ahead of print].

In this study, we sought to document the efficiency of primer extension capture (PEC) as a method to enrich DNA eluates of targeted DNA molecules and remove nontarget molecules from pools containing both. Efficiency of the method was estimated by comparing number of "copies in" to "copies out" by quantitative polymerase chain reaction. PEC retention of DNA targets ranging 109-288 base pairs (bps) in length was 15.88-2.14% (i.e., loss of 84.12-97.86% of target molecules). Experimental modifications of the PEC method resulted in no significant improvements. However, the benefit of PEC was revealed in its ability to remove most nontarget DNA molecules (99.99%). We also discovered that many (56.69%) of the target molecules are "lost" prior to their immobilization on the streptavidin-coated beads. These estimates of methodological efficiency are directly comparable to previous ones observed following "fishing" for DNA, an alternative method for DNA enrichment.

RevDate: 2018-12-14

Esposito U, Das R, Syed S, et al (2018)

Ancient Ancestry Informative Markers for Identifying Fine-Scale Ancient Population Structure in Eurasians.

Genes, 9(12): pii:genes9120625.

The rapid accumulation of ancient human genomes from various areas and time periods potentially enables the expansion of studies of biodiversity, biogeography, forensics, population history, and epidemiology into past populations. However, most ancient DNA (aDNA) data were generated through microarrays designed for modern-day populations, which are known to misrepresent the population structure. Past studies addressed these problems by using ancestry informative markers (AIMs). It is, thereby, unclear whether AIMs derived from contemporary human genomes can capture ancient population structures, and whether AIM-finding methods are applicable to aDNA, provided that the high missingness rates in ancient-and oftentimes haploid-DNA can also distort the population structure. Here, we define ancient AIMs (aAIMs) and develop a framework to evaluate established and novel AIM-finding methods in identifying the most informative markers. We show that aAIMs identified by a novel principal component analysis (PCA)-based method outperform all of the competing methods in classifying ancient individuals into populations and identifying admixed individuals. In some cases, predictions made using the aAIMs were more accurate than those made with a complete marker set. We discuss the features of the ancient Eurasian population structure and strategies to identify aAIMs. This work informs the design of single nucleotide polymorphism (SNP) microarrays and the interpretation of aDNA results, which enables a population-wide testing of primordialist theories.

RevDate: 2018-12-11

Rascovan N, Sjögren KG, Kristiansen K, et al (2018)

Emergence and Spread of Basal Lineages of Yersinia pestis during the Neolithic Decline.

Cell pii:S0092-8674(18)31464-8 [Epub ahead of print].

Between 5,000 and 6,000 years ago, many Neolithic societies declined throughout western Eurasia due to a combination of factors that are still largely debated. Here, we report the discovery and genome reconstruction of Yersiniapestis, the etiological agent of plague, in Neolithic farmers in Sweden, pre-dating and basal to all modern and ancient known strains of this pathogen. We investigated the history of this strain by combining phylogenetic and molecular clock analyses of the bacterial genome, detailed archaeological information, and genomic analyses from infected individuals and hundreds of ancient human samples across Eurasia. These analyses revealed that multiple and independent lineages of Y. pestis branched and expanded across Eurasia during the Neolithic decline, spreading most likely through early trade networks rather than massive human migrations. Our results are consistent with the existence of a prehistoric plague pandemic that likely contributed to the decay of Neolithic populations in Europe.

RevDate: 2018-12-06

Fischer CE, Lefort A, Pemonge MH, et al (2018)

The multiple maternal legacy of the Late Iron Age group of Urville-Nacqueville (France, Normandy) documents a long-standing genetic contact zone in northwestern France.

PloS one, 13(12):e0207459 pii:PONE-D-18-08273.

The compilation of archaeological and genetic data for ancient European human groups has provided persuasive evidence for a complex series of migrations, population replacements and admixture until the Bronze Age. If the Bronze-to-Iron Age transition has been well documented archaeologically, ancient DNA (aDNA) remains rare for the latter period and does not precisely reflect the genetic diversity of European Celtic groups. In order to document the evolution of European communities, we analysed 45 individuals from the Late Iron Age (La Tène) Urville-Nacqueville necropolis in northwestern France, a region recognized as a major cultural contact zone between groups from both sides of the Channel. The characterization of 37 HVS-I mitochondrial sequences and 40 haplogroups provided the largest maternal gene pool yet recovered for the European Iron Age. First, descriptive analyses allowed us to demonstrate the presence of substantial amounts of steppe-related mitochondrial ancestry in the community, which is consistent with the expansion of Bell Beaker groups bearing an important steppe legacy in northwestern Europe at approximately 2500 BC. Second, maternal genetic affinities highlighted with Bronze Age groups from Great Britain and the Iberian Peninsula regions tends to support the idea that the continuous cultural exchanges documented archaeologically across the Channel and along the Atlantic coast (during and after the Bronze Age period) were accompanied by significant gene flow. Lastly, our results suggest a maternal genetic continuity between Bronze Age and Iron Age groups that would argue in favour of a cultural transition linked to progressive local economic changes rather than to a massive influx of allochthone groups. The palaeogenetic data gathered for the Urville-Nacqueville group constitute an important step in the biological characterization of European Iron age groups. Clearly, more numerous and diachronic aDNA data are needed to fully understand the complex relationship between the cultural and biological evolution of groups from the period.

RevDate: 2018-12-05

Winkel T, Aguirre MG, Arizio CM, et al (2018)

Discontinuities in quinoa biodiversity in the dry Andes: An 18-century perspective based on allelic genotyping.

PloS one, 13(12):e0207519 pii:PONE-D-18-10369.

History and environment shape crop biodiversity, particularly in areas with vulnerable human communities and ecosystems. Tracing crop biodiversity over time helps understand how rural societies cope with anthropogenic or climatic changes. Exceptionally well preserved ancient DNA of quinoa (Chenopodium quinoa Willd.) from the cold and arid Andes of Argentina has allowed us to track changes and continuities in quinoa diversity over 18 centuries, by coupling genotyping of 157 ancient and modern seeds by 24 SSR markers with cluster and coalescence analyses. Cluster analyses revealed clear population patterns separating modern and ancient quinoas. Coalescence-based analyses revealed that genetic drift within a single population cannot explain genetic differentiation among ancient and modern quinoas. The hypothesis of a genetic bottleneck related to the Spanish Conquest also does not seem to apply at a local scale. Instead, the most likely scenario is the replacement of preexisting quinoa gene pools with new ones of lower genetic diversity. This process occurred at least twice in the last 18 centuries: first, between the 6th and 12th centuries-a time of agricultural intensification well before the Inka and Spanish conquests-and then between the 13th century and today-a period marked by farming marginalization in the late 19th century likely due to a severe multidecadal drought. While these processes of local gene pool replacement do not imply losses of genetic diversity at the metapopulation scale, they support the view that gene pool replacement linked to social and environmental changes can result from opposite agricultural trajectories.

RevDate: 2018-12-05

Zalloua P, Collins CJ, Gosling A, et al (2018)

Ancient DNA of Phoenician remains indicates discontinuity in the settlement history of Ibiza.

Scientific reports, 8(1):17567 pii:10.1038/s41598-018-35667-y.

Ibiza was permanently settled around the 7th century BCE by founders arriving from west Phoenicia. The founding population grew significantly and reached its height during the 4th century BCE. We obtained nine complete mitochondrial genomes from skeletal remains from two Punic necropoli in Ibiza and a Bronze Age site from Formentara. We also obtained low coverage (0.47X average depth) of the genome of one individual, directly dated to 361-178 cal BCE, from the Cas Molí site on Ibiza. We analysed and compared ancient DNA results with 18 new mitochondrial genomes from modern Ibizans to determine the ancestry of the founders of Ibiza. The mitochondrial results indicate a predominantly recent European maternal ancestry for the current Ibizan population while the whole genome data suggest a significant Eastern Mediterranean component. Our mitochondrial results suggest a genetic discontinuity between the early Phoenician settlers and the island's modern inhabitants. Our data, while limited, suggest that the Eastern or North African influence in the Punic population of Ibiza was primarily male dominated.

RevDate: 2018-12-05

Thompson TQ, Bellinger MR, O'Rourke SM, et al (2018)

Anthropogenic habitat alteration leads to rapid loss of adaptive variation and restoration potential in wild salmon populations.

Proceedings of the National Academy of Sciences of the United States of America pii:1811559115 [Epub ahead of print].

Phenotypic variation is critical for the long-term persistence of species and populations. Anthropogenic activities have caused substantial shifts and reductions in phenotypic variation across diverse taxa, but the underlying mechanism(s) (i.e., phenotypic plasticity and/or genetic evolution) and long-term consequences (e.g., ability to recover phenotypic variation) are unclear. Here we investigate the widespread and dramatic changes in adult migration characteristics of wild Chinook salmon caused by dam construction and other anthropogenic activities. Strikingly, we find an extremely robust association between migration phenotype (i.e., spring-run or fall-run) and a single locus, and that the rapid phenotypic shift observed after a recent dam construction is explained by dramatic allele frequency change at this locus. Furthermore, modeling demonstrates that continued selection against the spring-run phenotype could rapidly lead to complete loss of the spring-run allele, and an empirical analysis of populations that have already lost the spring-run phenotype reveals they are not acting as sustainable reservoirs of the allele. Finally, ancient DNA analysis suggests the spring-run allele was abundant in historical habitat that will soon become accessible through a large-scale restoration (i.e., dam removal) project, but our findings suggest that widespread declines and extirpation of the spring-run phenotype and allele will challenge reestablishment of the spring-run phenotype in this and future restoration projects. These results reveal the mechanisms and consequences of human-induced phenotypic change and highlight the need to conserve and restore critical adaptive variation before the potential for recovery is lost.

RevDate: 2018-11-30

Epp LS, Kruse S, Kath NJ, et al (2018)

Temporal and spatial patterns of mitochondrial haplotype and species distributions in Siberian larches inferred from ancient environmental DNA and modeling.

Scientific reports, 8(1):17436 pii:10.1038/s41598-018-35550-w.

Changes in species' distributions are classically projected based on their climate envelopes. For Siberian forests, which have a tremendous significance for vegetation-climate feedbacks, this implies future shifts of each of the forest-forming larch (Larix) species to the north-east. However, in addition to abiotic factors, reliable projections must assess the role of historical biogeography and biotic interactions. Here, we use sedimentary ancient DNA and individual-based modelling to investigate the distribution of larch species and mitochondrial haplotypes through space and time across the treeline ecotone on the southern Taymyr peninsula, which at the same time presents a boundary area of two larch species. We find spatial and temporal patterns, which suggest that forest density is the most influential driver determining the precise distribution of species and mitochondrial haplotypes. This suggests a strong influence of competition on the species' range shifts. These findings imply possible climate change outcomes that are directly opposed to projections based purely on climate envelopes. Investigations of such fine-scale processes of biodiversity change through time are possible using paleoenvironmental DNA, which is available much more readily than visible fossils and can provide information at a level of resolution that is not reached in classical palaeoecology.

RevDate: 2018-11-30

Eisenhofer R, Minich JJ, Marotz C, et al (2018)

Contamination in Low Microbial Biomass Microbiome Studies: Issues and Recommendations.

Trends in microbiology pii:S0966-842X(18)30253-1 [Epub ahead of print].

Next-generation sequencing approaches in microbiome research have allowed surveys of microbial communities, their genomes, and their functions with higher sensitivity than ever before. However, this sensitivity is a double-edged sword because these tools also efficiently detect contaminant DNA and cross-contamination, which can confound the interpretation of microbiome data. Therefore, there is an urgent need to integrate key controls into microbiome research to improve the integrity of microbiome studies. Here, we review how contaminant DNA and cross-contamination arise within microbiome studies and discuss their negative impacts, especially during the analysis of low microbial biomass samples. We then identify several key measures that researchers can implement to reduce the impact of contaminant DNA and cross-contamination during microbiome research. We put forward a set of minimal experimental criteria, the 'RIDE' checklist, to improve the validity of future low microbial biomass research.

RevDate: 2018-11-29

Baichoo S, Souilmi Y, Panji S, et al (2018)

Developing reproducible bioinformatics analysis workflows for heterogeneous computing environments to support African genomics.

BMC bioinformatics, 19(1):457 pii:10.1186/s12859-018-2446-1.

BACKGROUND: The Pan-African bioinformatics network, H3ABioNet, comprises 27 research institutions in 17 African countries. H3ABioNet is part of the Human Health and Heredity in Africa program (H3Africa), an African-led research consortium funded by the US National Institutes of Health and the UK Wellcome Trust, aimed at using genomics to study and improve the health of Africans. A key role of H3ABioNet is to support H3Africa projects by building bioinformatics infrastructure such as portable and reproducible bioinformatics workflows for use on heterogeneous African computing environments. Processing and analysis of genomic data is an example of a big data application requiring complex interdependent data analysis workflows. Such bioinformatics workflows take the primary and secondary input data through several computationally-intensive processing steps using different software packages, where some of the outputs form inputs for other steps. Implementing scalable, reproducible, portable and easy-to-use workflows is particularly challenging.

RESULTS: H3ABioNet has built four workflows to support (1) the calling of variants from high-throughput sequencing data; (2) the analysis of microbial populations from 16S rDNA sequence data; (3) genotyping and genome-wide association studies; and (4) single nucleotide polymorphism imputation. A week-long hackathon was organized in August 2016 with participants from six African bioinformatics groups, and US and European collaborators. Two of the workflows are built using the Common Workflow Language framework (CWL) and two using Nextflow. All the workflows are containerized for improved portability and reproducibility using Docker, and are publicly available for use by members of the H3Africa consortium and the international research community.

CONCLUSION: The H3ABioNet workflows have been implemented in view of offering ease of use for the end user and high levels of reproducibility and portability, all while following modern state of the art bioinformatics data processing protocols. The H3ABioNet workflows will service the H3Africa consortium projects and are currently in use. All four workflows are also publicly available for research scientists worldwide to use and adapt for their respective needs. The H3ABioNet workflows will help develop bioinformatics capacity and assist genomics research within Africa and serve to increase the scientific output of H3Africa and its Pan-African Bioinformatics Network.

RevDate: 2018-11-27

Cascini M, Mitchell KJ, Cooper A, et al (2018)

Reconstructing the Evolution of Giant Extinct Kangaroos: Comparing the Utility of DNA, Morphology, and Total Evidence.

Systematic biology pii:5210880 [Epub ahead of print].

Combined "total evidence" analysis of molecular and morphological data offers the opportunity to objectively merge fossils into the tree of life, and challenges the primacy of solely DNA based phylogenetic and dating inference, even among modern taxa. To investigate the relative utility of DNA, morphology, and total evidence for evolutionary inference, we sequenced the first near-complete mitochondrial genomes from extinct Australian megafauna: a 40-50 thousand year old giant short-faced kangaroo (Simosthenurus occidentalis) and giant wallaby (Protemnodon anak). We analysed the ancient DNA and fossil data alongside comparable data from extant species to infer phylogeny, divergence times, and ancestral body mass among macropods (kangaroos and wallabies). Our results confirm a close relationship between Protemnodon and the iconic kangaroo genus complex "Macropus", and unite the giant Simothenurus with the hare-sized Lagostrophus fasciatus (banded hare-wallaby), suggesting that the latter is the closest living link to the once diverse sthenurine kangaroo radiation. We find that large body size evolved multiple times among kangaroos, coincident with expansion of open woodland habitats beginning in the Late Miocene. In addition, our results suggest that morphological data mislead macropod phylogeny reconstruction and in turn can distort total evidence estimation of divergence dates. However, a novel result with potentially broad application is that the accuracy and precision of reconstructing ancestral body mass was improved by tracing body mass on morphological branch lengths. This is likely due to positive allometric correlation between morphological and body size variation - a relationship that may be masked or even misleadingly inverted with the temporal or molecular branch lengths that typically underpin ancestral body size reconstruction. Our study supports complementary roles for DNA and morphology in evolutionary inference, and opens a new window into the evolution of Australia's unique marsupial fauna.

RevDate: 2018-11-30

Lamnidis TC, Majander K, Jeong C, et al (2018)

Ancient Fennoscandian genomes reveal origin and spread of Siberian ancestry in Europe.

Nature communications, 9(1):5018 pii:10.1038/s41467-018-07483-5.

European population history has been shaped by migrations of people, and their subsequent admixture. Recently, ancient DNA has brought new insights into European migration events linked to the advent of agriculture, and possibly to the spread of Indo-European languages. However, little is known about the ancient population history of north-eastern Europe, in particular about populations speaking Uralic languages, such as Finns and Saami. Here we analyse ancient genomic data from 11 individuals from Finland and north-western Russia. We show that the genetic makeup of northern Europe was shaped by migrations from Siberia that began at least 3500 years ago. This Siberian ancestry was subsequently admixed into many modern populations in the region, particularly into populations speaking Uralic languages today. Additionally, we show that ancestors of modern Saami inhabited a larger territory during the Iron Age, which adds to the historical and linguistic information about the population history of Finland.

RevDate: 2018-11-27

Kosintsev P, Mitchell KJ, Devièse T, et al (2018)

Evolution and extinction of the giant rhinoceros Elasmotherium sibiricum sheds light on late Quaternary megafaunal extinctions.

Nature ecology & evolution pii:10.1038/s41559-018-0722-0 [Epub ahead of print].

Understanding extinction events requires an unbiased record of the chronology and ecology of victims and survivors. The rhinoceros Elasmotherium sibiricum, known as the 'Siberian unicorn', was believed to have gone extinct around 200,000 years ago-well before the late Quaternary megafaunal extinction event. However, no absolute dating, genetic analysis or quantitative ecological assessment of this species has been undertaken. Here, we show, by accelerator mass spectrometry radiocarbon dating of 23 individuals, including cross-validation by compound-specific analysis, that E. sibiricum survived in Eastern Europe and Central Asia until at least 39,000 years ago, corroborating a wave of megafaunal turnover before the Last Glacial Maximum in Eurasia, in addition to the better-known late-glacial event. Stable isotope data indicate a dry steppe niche for E. sibiricum and, together with morphology, a highly specialized diet that probably contributed to its extinction. We further demonstrate, with DNA sequencing data, a very deep phylogenetic split between the subfamilies Elasmotheriinae and Rhinocerotinae that includes all the living rhinoceroses, settling a debate based on fossil evidence and confirming that the two lineages had diverged by the Eocene. As the last surviving member of the Elasmotheriinae, the demise of the 'Siberian unicorn' marked the extinction of this subfamily.

RevDate: 2018-11-27

Namouchi A, Guellil M, Kersten O, et al (2018)

Integrative approach using Yersinia pestis genomes to revisit the historical landscape of plague during the Medieval Period.

Proceedings of the National Academy of Sciences of the United States of America pii:1812865115 [Epub ahead of print].

Over the last few years, genomic studies on Yersinia pestis, the causative agent of all known plague epidemics, have considerably increased in numbers, spanning a period of about 5,000 y. Nonetheless, questions concerning historical reservoirs and routes of transmission remain open. Here, we present and describe five genomes from the second half of the 14th century and reconstruct the evolutionary history of Y. pestis by reanalyzing previously published genomes and by building a comprehensive phylogeny focused on strains attributed to the Second Plague Pandemic (14th to 18th century). Corroborated by historical and ecological evidence, the presented phylogeny, which includes our Y. pestis genomes, could support the hypothesis of an entry of plague into Western European ports through distinct waves of introduction during the Medieval Period, possibly by means of fur trade routes, as well as the recirculation of plague within the human population via trade routes and human movement.

RevDate: 2018-11-24

Santi R, Rizzolo P, Pietragalla M, et al (2018)

The antiquity of hydrocephalus: the first full palaeo-neuropathological description.

Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology pii:10.1007/s10072-018-3643-4 [Epub ahead of print].

The Pathology Museum of the University of Florence houses a rich collection of anatomical specimens and over a hundred waxworks portraying pathological conditions occurring in the nineteenth century, when the museum was established. Clinical and autopsy findings of these cases can still be retrieved from the original museum catalogue, offering a rare opportunity for retrospective palaeo-pathological diagnostics. We present a historical case of severe hydrocephalus backed by modern-day anthropological, radiological and molecular analyses conducted on the skeleton of an 18-month-old male infant deceased in 1831. Luigi Calamai (1796-1851), a wax craftsman of La Specola workshop in Florence, was commissioned to create a life-sized wax model of the child's head, neck and upper thorax. This artwork allows us to appreciate the cranial and facial alterations determined by 30 lb of cerebrospinal fluid (CSF) accumulated within the cerebral ventricular system. Based on the autopsy report, gross malformations of the neural tube, tumours and haemorrhage could be excluded. A molecular approach proved helpful in confirming sex. We present this case as the so-far most compelling case of hydrocephalus in palaeo-pathological research.

RevDate: 2018-11-23

Buckley M, Lawless C, N Rybczynski (2018)

Collagen sequence analysis of fossil camels, Camelops and c.f. Paracamelus, from the Arctic and sub-Arctic of Plio-Pleistocene North America.

Journal of proteomics pii:S1874-3919(18)30404-4 [Epub ahead of print].

Proteomic analyses of ancient remains are increasing, with great potential to recover phylogenetic information on extinct animals beyond the reach of ancient DNA, but its limitations remain unclear. Here we carry out LC-MS/MS sequence analysis of a ~3.5 million year old specimen along with the younger Pleistocene remains of the Yukon giant camel (c.f. Paracamelus) and the western camel (Camelops hesternus) for comparison with complete sequences to both extant camels (Bactrian and Dromedary) and the alpaca. Although not complete (~75-80% sequence coverage), no amino acid sequence differences were confidently observed between the giant camels and the extant Dromedary, indicative of a closer relationship than that of the extant Bactrian lineage. However, multiple amino acid changes were observed for the western camel (Camelops) collagen sequence, placing it as a sister group to these members of Camelini tribe consistent recent ancient DNA analyses. Although this supports a role for the sequencing of ancient collagen in the understanding of vertebrate evolution, we also highlight the limitations in phylogenetic reconstructions based on partial sequence data retrieved from proteomic analyses, particularly, the impact of omitting even only a single peptide on the resulting tree topology. The presence of other non-collagenous proteins, such as biglycan and PEDF, indicates a further resource for phylogenetic information, but none more promising than the degraded camel albumin observed in the Plio-Pleistocene specimen. SIGNIFICANCE: As proteomics is becoming more frequently used in the study of ancient proteins, an emerging field known as 'palaeoproteomics' (or 'paleoproteomics'), understanding the limitations of the technique is essential. Here, through the study of the oldest undisputed collagen sequences obtained from proteomics, we confirm that some peptides following diagenetic modifications of tryptic sites are no longer matched with standard searches, but can be matched with Error Tolerant searches. We also demonstrate the ability to retrieve phylogenetic information consistent with that of ancient DNA methods, but that with the omission of only one or more key peptides, the inferred evolutionary relationships change. This is a significant finding for the field of palaeoproteomics implying a need for better understanding the particular composition of the partial sequences retrieved from proteomic analyses.

RevDate: 2018-11-29

Wood JR, Díaz FP, Latorre C, et al (2018)

Plant pathogen responses to Late Pleistocene and Holocene climate change in the central Atacama Desert, Chile.

Scientific reports, 8(1):17208 pii:10.1038/s41598-018-35299-2.

Future climate change has the potential to alter the distribution and prevalence of plant pathogens, which may have significant implications for both agricultural crops and natural plant communities. However, there are few long-term datasets against which modelled predictions of pathogen responses to climate change can be tested. Here, we use 18S metabarcoding of 28 rodent middens (solidified deposits of rodent coprolites and nesting material) from the Central Atacama, spanning the last ca. 49 ka, to provide the first long-term late Quaternary record of change in plant pathogen communities in response to changing climate. Plant pathogen richness was significantly greater in middens deposited during the Central Andean Pluvial Event (CAPE); a period of increased precipitation between 17.5-8.5 ka. Moreover, the occurrence frequency of Pucciniaceae (rust fungi) was significantly greater during the CAPE, and the highest relative abundances for five additional potentially pathogenic taxa also occurred during this period. The results demonstrate the promising potential for ancient DNA analysis of late Quaternary samples to reveal insights into how plant pathogens responded to past climatic and environmental change, which could help predict how pathogens may responded to future change.

RevDate: 2018-11-20

Andrew C, Diez J, James TY, et al (2018)

Fungarium specimens: a largely untapped source in global change biology and beyond.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 374(1763): pii:rstb.2017.0392.

For several hundred years, millions of fungal sporocarps have been collected and deposited in worldwide collections (fungaria) to support fungal taxonomy. Owing to large-scale digitization programs, metadata associated with the records are now becoming publicly available, including information on taxonomy, sampling location, collection date and habitat/substrate information. This metadata, as well as data extracted from the physical fungarium specimens themselves, such as DNA sequences and biochemical characteristics, provide a rich source of information not only for taxonomy but also for other lines of biological inquiry. Here, we highlight and discuss how this information can be used to investigate emerging topics in fungal global change biology and beyond. Fungarium data are a prime source of knowledge on fungal distributions and richness patterns, and for assessing red-listed and invasive species. Information on collection dates has been used to investigate shifts in fungal distributions as well as phenology of sporocarp emergence in response to climate change. In addition to providing material for taxonomy and systematics, DNA sequences derived from the physical specimens provide information about fungal demography, dispersal patterns, and are emerging as a source of genomic data. As DNA analysis technologies develop further, the importance of fungarium specimens as easily accessible sources of information will likely continue to grow.This article is part of the theme issue 'Biological collections for understanding biodiversity in the Anthropocene'.

RevDate: 2018-11-16

O'Connor TD (2018)

Native American Genomic Diversity through Ancient DNA.

Cell, 175(5):1173-1174.

Ancient DNA is a powerful tool to understand the evolutionary dynamics of both current and ancestral populations. Posth et al. use ancient DNA to elucidate important questions surrounding the peopling of Central and South America, giving us greater insights into the ancestry of genetically understudied populations.

RevDate: 2018-11-13

Woods R, Turvey ST, Brace S, et al (2018)

Ancient DNA of the extinct Jamaican monkey Xenothrix reveals extreme insular change within a morphologically conservative radiation.

Proceedings of the National Academy of Sciences of the United States of America pii:1808603115 [Epub ahead of print].

The insular Caribbean until recently contained a diverse mammal fauna including four endemic platyrrhine primate species, all of which died out during the Holocene. Previous morphological studies have attempted to establish how these primates are related to fossil and extant platyrrhines, whether they represent ancient or recent colonists, and whether they constitute a monophyletic group. These efforts have generated multiple conflicting hypotheses, from close sister-taxon relationships with several different extant platyrrhines to derivation from a stem platyrrhine lineage outside the extant Neotropical radiation. This diversity of opinion reflects the fact that Caribbean primates were morphologically extremely unusual, displaying numerous autapomorphies and apparently derived conditions present across different platyrrhine clades. Here we report ancient DNA data for an extinct Caribbean primate: a limited-coverage entire mitochondrial genome and seven regions of nuclear genome for the most morphologically derived taxon, the Jamaican monkey Xenothrix mcgregori We demonstrate that Xenothrix is part of the existing platyrrhine radiation rather than a late-surviving stem platyrrhine, despite its unusual adaptations, and falls within the species-rich but morphologically conservative titi monkey clade (Callicebinae) as sister to the newly recognized genus Cheracebus These results are not congruent with previous morphology-based hypotheses and suggest that even morphologically conservative lineages can exhibit phenetic plasticity in novel environments like those found on islands. Xenothrix and Cheracebus diverged ca. 11 Ma, but primates have been present in the Caribbean since 17.5-18.5 Ma, indicating that Caribbean primate diversity was generated by multiple over-water colonizations.

RevDate: 2018-11-16

Posth C, Nakatsuka N, Lazaridis I, et al (2018)

Reconstructing the Deep Population History of Central and South America.

Cell, 175(5):1185-1197.e22.

We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least ∼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by ∼4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.

RevDate: 2018-11-19

Wade L (2018)

Ancient DNA tracks migrations around Americas.

Science (New York, N.Y.), 362(6415):627-628.

RevDate: 2018-11-08

Quillen EE, Norton HL, Parra EJ, et al (2018)

Shades of complexity: New perspectives on the evolution and genetic architecture of human skin.

American journal of physical anthropology [Epub ahead of print].

Like many highly variable human traits, more than a dozen genes are known to contribute to the full range of skin color. However, the historical bias in favor of genetic studies in European and European-derived populations has blinded us to the magnitude of pigmentation's complexity. As deliberate efforts are being made to better characterize diverse global populations and new sequencing technologies, better measurement tools, functional assessments, predictive modeling, and ancient DNA analyses become more widely accessible, we are beginning to appreciate how limited our understanding of the genetic bases of human skin color have been. Novel variants in genes not previously linked to pigmentation have been identified and evidence is mounting that there are hundreds more variants yet to be found. Even for genes that have been exhaustively characterized in European populations like MC1R, OCA2, and SLC24A5, research in previously understudied groups is leading to a new appreciation of the degree to which genetic diversity, epistatic interactions, pleiotropy, admixture, global and local adaptation, and cultural practices operate in population-specific ways to shape the genetic architecture of skin color. Furthermore, we are coming to terms with how factors like tanning response and barrier function may also have influenced selection on skin throughout human history. By examining how our knowledge of pigmentation genetics has shifted in the last decade, we can better appreciate how far we have come in understanding human diversity and the still long road ahead for understanding many complex human traits.

RevDate: 2018-11-14

Guedes L, Dias O, Neto J, et al (2018)

First Paleogenetic Evidence of Probable Syphilis and Treponematoses Cases in the Brazilian Colonial Period.

BioMed research international, 2018:8304129.

Despite interest in the origins of syphilis, paleopathological analysis has not provided answers, and paleogenetic diagnosis remains a challenge. Even venereal syphilis has low infectivity which means there are few circulating bacteria for most of the individual's life. Human remains recovered from the Nossa Senhora do Carmo Church (17th to 19th centuries) and the Praça XV Cemetery (18th to 19th centuries), Rio de Janeiro, Brazil, were subjected to Treponema paleogenetic analysis. Historical data point to endemic treponemal infections in the city, including venereal syphilis. Based on the physiopathology of Treponema pallidum infection, 25 samples, mostly from skull remains of young adults, with no visible paleopathological evidence of treponematoses, were analyzed. PCR with three molecular targets, tpp47, polA, and tpp15, were applied. Ancient DNA tpp15 sequences were recovered from two young adults from each archaeological site and revealed the polymorphism that characterizes T. p. subsp. pallidum in a female up to 18 years old, suggesting a probable case of syphilis infection. The results indicated that the epidemiological context and the physiopathology of the disease should be considered in syphilis paleogenetic detection. The findings of Treponema sp. aDNA are consistent with historical documents that describe venereal syphilis and yaws as endemic diseases in Rio de Janeiro. Data on the epidemiological characteristics of the disease and its pathophysiology offer new perspectives in paleopathology.

RevDate: 2018-11-29

Hefetz I, Einot N, Faerman M, et al (2018)

Touch DNA: The effect of the deposition pressure on the quality of latent fingermarks and STR profiles.

Forensic science international. Genetics, 38:105-112 pii:S1872-4973(18)30157-1 [Epub ahead of print].

Latent fingermarks (FMs) present unique, and sometimes the only, evidence found at a crime scene. Several factors affect their quality, including deposition pressure (DP). Its effect on FM size and quality, and on STR amplification success rate, is an emerging area of interest in forensic science. This study examined 540 FM samples, each consisting of index, middle and ring fingers, deposited by 30 donors on glass, polythene (PE) and paper under a range of weights from 0.1 to 10 kg. Both length and width of FMs increased with the increasing DP. FMs deposited under lower (≤0.5 kg) DPs varied in size (p < 0.01), while those deposited at higher (≥3 kg) DPs were more consistent. FM quality on glass and PE, as determined by the AFIS minutiae count and by a fingerprint examiner on a scale from 0 to 4, improved with the increasing DP, but it deteriorated on PE at DP of 10 kg. FM quality on paper continued to improve from DP of 1 kg up to the maximum DP of 10 kg. The effect DP has on the efficacy of DNA profiling from latent FMs was significant as shown by an increase in the DNA amount recovered, the number of amplified loci per FM sample, and the number of forensically useful DNA profiles (defined here as those with ≥8 full STR loci detected) as DP increased. This effect was most pronounced with PE (R = 0.98) and paper (R = 0.96). Altogether, the success rate of DNA profiling varied from 16.3% in FMs deposited on paper to 21.2% and 22.5% of those on PE and glass. The highest number of useful DNA profiles was obtained from glass under DP of 10 kg. Forensically useful FMs obtained at low (≤1 kg) DP from all three substrates significantly outnumbered that of STR profiles, while an opposite, though less pronounced trend, was observed at high (≥3 kg) DP on PE and paper. Application of the simple device for collecting of FMs under controlled pressure designed for this study, and the palm-up mode of FM deposition as described, allowed us to eliminate the undesirable effect of the hand self-weight and to objectively assess the actual effect of increasing DP on FM size and quality, as well as on the efficacy of DNA profiling.

RevDate: 2018-11-20

Taylor W, Shnaider S, Abdykanova A, et al (2018)

Early pastoral economies along the Ancient Silk Road: Biomolecular evidence from the Alay Valley, Kyrgyzstan.

PloS one, 13(10):e0205646 pii:PONE-D-18-20515.

The Silk Road was an important trade route that channeled trade goods, people, plants, animals, and ideas across the continental interior of Eurasia, fueling biotic exchange and key social developments across the Old World. Nestled between the Pamir and Alay ranges at a baseline elevation of nearly 3000m, Kyrgyzstan's high Alay Valley forms a wide geographic corridor that comprised one of the primary channels of the ancient Silk Road. Recent archaeological survey reveals a millennia-long history of pastoral occupation of Alay from the early Bronze Age through the Medieval period, and a stratified Holocene sequence at the site of Chegirtke Cave. Faunal remains were recovered from test excavations as well as surface collection of material from recent marmot activity. Although recovered specimens were highly fragmented and mostly unidentifiable using traditional zooarchaeological methods, species identification via collagen mass fingerprinting (ZooMS) coupled with sex and first-generation hybrid identification through ancient DNA enabled preliminary characterization of the animal economy of Alay herders. Our new results indicate primary reliance on sheep at Chegirtke Cave (ca. 2200 BCE), with cattle and goat also present. The discovery of a large grinding stone at a spatially associated Bronze or Iron Age habitation structure suggests a mixed agropastoral economic strategy, rather than a unique reliance on domestic animals. Radiocarbon-dated faunal assemblages from habitation structures at nearby localities in the Alay Valley demonstrate the presence of domestic horse, as well as Bactrian camel during later periods. The current study reveals that agropastoral occupation of the high-mountain Alay corridor started millennia before the formal establishment of the Silk Road, and posits that ZooMS, when paired with radiocarbon dates and ancient DNA, is a powerful and cost-effective tool for investigating shifts in the use of animal domesticates in early pastoral economies.

RevDate: 2018-10-30

Geigl EM, T Grange (2018)

Ancient DNA: The quest for the best.

Molecular ecology resources, 18(6):1185-1187.

It is the dream of all researchers working with ancient DNA to identify prior to DNA extraction from bone the specimens or specific zones within them that contain the highest proportion of endogenous DNA. As it impacts the sacrifice of precious ancient specimens and the financial support needed for the analyses, the question is of high importance to the scientific field of palaeogenomics. The "Holy Grail" of palaeogenomics was reached when Cristina Gamba et al. () discovered that it was in the petrosal part of the temporal bone, the densest part of the mammalian skeleton, where DNA is exceptionally well preserved. As a consequence, osteological collections experienced a rush from palaeogenomicists to "harvest" these precious bone parts. In this issue of Molecular Ecology Resources, Alberti et al. () describe the discovery of another promising source of relatively well-preserved endogenous DNA, that they had identified through computed tomography (CT scans), the outermost layer of cortical bone. These bones being larger and more abundant than petrous bones, this discovery increases markedly the source material for high-quality palaeogenomic studies and releases the pressure on osteological collections.

RevDate: 2018-11-23

Zarrillo S, Gaikwad N, Lanaud C, et al (2018)

The use and domestication of Theobroma cacao during the mid-Holocene in the upper Amazon.

Nature ecology & evolution, 2(12):1879-1888.

Cacao (Theobroma cacao L.) is an important economic crop, yet studies of its domestication history and early uses are limited. Traditionally, cacao is thought to have been first domesticated in Mesoamerica. However, genomic research shows that T. cacao's greatest diversity is in the upper Amazon region of northwest South America, pointing to this region as its centre of origin. Here, we report cacao use identified by three independent lines of archaeological evidence-cacao starch grains, absorbed theobromine residues and ancient DNA-dating from approximately 5,300 years ago recovered from the Santa Ana-La Florida (SALF) site in southeast Ecuador. To our knowledge, these findings constitute the earliest evidence of T. cacao use in the Americas and the first unequivocal archaeological example of its pre-Columbian use in South America. They also reveal the upper Amazon region as the oldest centre of cacao domestication yet identified.

RevDate: 2018-10-29

Tian JY, Li YC, Kong QP, et al (2018)

[The origin and evolution history of East Asian populations from genetic perspectives].

Yi chuan = Hereditas, 40(10):814-824.

East Asia is widely concerned as one of the important places for the dispersal and evolution of the Anatomically Modern Human (AMH). How the diverse ethnic groups in East Asia originated and diversified is also widely focused by different disciplines of Anthropology. The adoption of genetic data had provided new clues for reconstructing the genetic history of East Asian populations. Genetic studies supported the hypothesis that the AMHs originated from Africa's Homo sapiens at about 200 kilo years ago (kya) and then migrated out of Africa at ~100 kya, followed by expansions into the whole East Asia since their arrival in Southern East Asia at 5~6 kya along the coastal route. Early Homo Sapiens might have genetic contribution to the non-African AMHs. Early settlement, cultural assimilation, population migration and genetic exchanges are crucial in the origination and evolution of East Asia populations. Previous studies made detailed analysis for the genetic history of East Asian populations, which largely resolved the longstanding divergence between archaeology and history. However, this needs further verification by whole-genome sequencing and ancient DNA studies. Here we briefly reviewed the progresses of genetic studies in exploring the population origin, dispersal and diversification in East Asia, which improved understanding of the evolution of East Asian populations. We also prospected the future of genetic studies in revealing the prehistory of East Asians.

RevDate: 2018-11-24

Zilberman U, Milevski I, Yegorov D, et al (2019)

A 3000 year old case of an unusual dental lesion: Pre-eruptive intracoronal resorption.

Archives of oral biology, 97:97-101.

OBJECTIVE: To determine the cause of a large dental lesion, tentatively identified as a case of pre-eruptive intra-coronal resorption (PEIR), in the permanent second mandibular molar of a young individual from an Iron Age cemetery at Tel Erani (Israel), dated to ca. 3000 years B.P. The provisional diagnosis was based on the massive size of the lesion in a young individual in whom the adjacent teeth were caries-free and showed no visible enamel defects.

DESIGN: The lower molars of Tel Erani on the affected side were radiographed and compared to radiographs of a modern clinical case of PEIR treated by one of us (U.Z) and the internal structure and mineral content of the lesion examined in detail using energy-dispersive X-ray spectroscopy (EDS).

RESULTS: The Tel Erani specimen closely resembled the modern clinical case of PEIR. Moreover, both cases occurred in young individuals in whom the adjacent teeth were caries-free. Examination with SEM revealed absence of dentine in the affected tooth from Tel Erani, together with changes in structure and mineral content characteristic of resorption.

CONCLUSIONS: Our study shows that the changes found in the lower second molar of the 3000 year old mandible from Tel Erani are characteristic of PEIR and demonstrate the antiquity of this condition.

RevDate: 2018-11-26

Cole TL, Rawlence NJ, Dussex N, et al (2018)

Ancient DNA of crested penguins: Testing for temporal genetic shifts in the world's most diverse penguin clade.

Molecular phylogenetics and evolution, 131:72-79 pii:S1055-7903(18)30627-4 [Epub ahead of print].

Human impacts have substantially reduced avian biodiversity in many parts of the world, particularly on isolated islands of the Pacific Ocean. The New Zealand archipelago, including its five subantarctic island groups, holds breeding grounds for a third of the world's penguin species, including several representatives of the diverse crested penguin genus Eudyptes. While this species-rich genus has been little studied genetically, recent population estimates indicate that several Eudyptes taxa are experiencing demographic declines. Although crested penguins are currently limited to southern regions of the New Zealand archipelago, prehistoric fossil and archaeological deposits suggest a wider distribution during prehistoric times, with breeding ranges perhaps extending to the North Island. Here, we analyse ancient, historic and modern DNA sequences to explore two hypotheses regarding the recent history of Eudyptes in New Zealand, testing for (1) human-driven extinction of Eudyptes lineages; and (2) reduced genetic diversity in surviving lineages. From 83 prehistoric bone samples, each tentatively identified as 'Eudyptes spp.', we genetically identified six prehistoric penguin taxa from mainland New Zealand, including one previously undescribed genetic lineage. Moreover, our Bayesian coalescent analyses indicated that, while the range of Fiordland crested penguin (E. pachyrhynchus) may have contracted markedly over the last millennium, genetic DNA diversity within this lineage has remained relatively constant. This result contrasts with human-driven biodiversity reductions previously detected in several New Zealand coastal vertebrate taxa.

RevDate: 2018-11-14

de Filippo C, Meyer M, K Prüfer (2018)

Quantifying and reducing spurious alignments for the analysis of ultra-short ancient DNA sequences.

BMC biology, 16(1):121 pii:10.1186/s12915-018-0581-9.

BACKGROUND: The study of ancient DNA is hampered by degradation, resulting in short DNA fragments. Advances in laboratory methods have made it possible to retrieve short DNA fragments, thereby improving access to DNA preserved in highly degraded, ancient material. However, such material contains large amounts of microbial contamination in addition to DNA fragments from the ancient organism. The resulting mixture of sequences constitutes a challenge for computational analysis, since microbial sequences are hard to distinguish from the ancient sequences of interest, especially when they are short.

RESULTS: Here, we develop a method to quantify spurious alignments based on the presence or absence of rare variants. We find that spurious alignments are enriched for mismatches and insertion/deletion differences and lack substitution patterns typical of ancient DNA. The impact of spurious alignments can be reduced by filtering on these features and by imposing a sample-specific minimum length cutoff. We apply this approach to sequences from four ~ 430,000-year-old Sima de los Huesos hominin remains, which contain particularly short DNA fragments, and increase the amount of usable sequence data by 17-150%. This allows us to place a third specimen from the site on the Neandertal lineage.

CONCLUSIONS: Our method maximizes the sequence data amenable to genetic analysis from highly degraded ancient material and avoids pitfalls that are associated with the analysis of ultra-short DNA sequences.

RevDate: 2018-11-14

Paijmans JLA, Barlow A, Förster DW, et al (2018)

Historical biogeography of the leopard (Panthera pardus) and its extinct Eurasian populations.

BMC evolutionary biology, 18(1):156 pii:10.1186/s12862-018-1268-0.

BACKGROUND: Resolving the historical biogeography of the leopard (Panthera pardus) is a complex issue, because patterns inferred from fossils and from molecular data lack congruence. Fossil evidence supports an African origin, and suggests that leopards were already present in Eurasia during the Early Pleistocene. Analysis of DNA sequences however, suggests a more recent, Middle Pleistocene shared ancestry of Asian and African leopards. These contrasting patterns led researchers to propose a two-stage hypothesis of leopard dispersal out of Africa: an initial Early Pleistocene colonisation of Asia and a subsequent replacement by a second colonisation wave during the Middle Pleistocene. The status of Late Pleistocene European leopards within this scenario is unclear: were these populations remnants of the first dispersal, or do the last surviving European leopards share more recent ancestry with their African counterparts?

RESULTS: In this study, we generate and analyse mitogenome sequences from historical samples that span the entire modern leopard distribution, as well as from Late Pleistocene remains. We find a deep bifurcation between African and Eurasian mitochondrial lineages (~ 710 Ka), with the European ancient samples as sister to all Asian lineages (~ 483 Ka). The modern and historical mainland Asian lineages share a relatively recent common ancestor (~ 122 Ka), and we find one Javan sample nested within these.

CONCLUSIONS: The phylogenetic placement of the ancient European leopard as sister group to Asian leopards suggests that these populations originate from the same out-of-Africa dispersal which founded the Asian lineages. The coalescence time found for the mitochondrial lineages aligns well with the earliest undisputed fossils in Eurasia, and thus encourages a re-evaluation of the identification of the much older putative leopard fossils from the region. The relatively recent ancestry of all mainland Asian leopard lineages suggests that these populations underwent a severe population bottleneck during the Pleistocene. Finally, although only based on a single sample, the unexpected phylogenetic placement of the Javan leopard could be interpreted as evidence for exchange of mitochondrial lineages between Java and mainland Asia, calling for further investigation into the evolutionary history of this subspecies.

RevDate: 2018-11-14

Silva NM, Rio J, Kreutzer S, et al (2018)

Bayesian estimation of partial population continuity using ancient DNA and spatially explicit simulations.

Evolutionary applications, 11(9):1642-1655 pii:EVA12655.

The retrieval of ancient DNA from osteological material provides direct evidence of human genetic diversity in the past. Ancient DNA samples are often used to investigate whether there was population continuity in the settlement history of an area. Methods based on the serial coalescent algorithm have been developed to test whether the population continuity hypothesis can be statistically rejected by analysing DNA samples from the same region but of different ages. Rejection of this hypothesis is indicative of a large genetic shift, possibly due to immigration occurring between two sampling times. However, this approach is only able to reject a model of full continuity model (a total absence of genetic input from outside), but admixture between local and immigrant populations may lead to partial continuity. We have recently developed a method to test for population continuity that explicitly considers the spatial and temporal dynamics of populations. Here, we extended this approach to estimate the proportion of genetic continuity between two populations, using ancient genetic samples. We applied our original approach to the question of the Neolithic transition in Central Europe. Our results confirmed the rejection of full continuity, but our approach represents an important step forward by estimating the relative contribution of immigrant farmers and of local hunter-gatherers to the final Central European Neolithic genetic pool. Furthermore, we show that a substantial proportion of genes brought by the farmers in this region were assimilated from other hunter-gatherer populations along the way from Anatolia, which was not detectable by previous continuity tests. Our approach is also able to jointly estimate demographic parameters, as we show here by finding both low density and low migration rate for pre-Neolithic hunter-gatherers. It provides a useful tool for the analysis of the numerous ancient DNA data sets that are currently being produced for many different species.

RevDate: 2018-11-14

Vajana E, Barbato M, Colli L, et al (2018)

Combining Landscape Genomics and Ecological Modelling to Investigate Local Adaptation of Indigenous Ugandan Cattle to East Coast Fever.

Frontiers in genetics, 9:385.

East Coast fever (ECF) is a fatal sickness affecting cattle populations of eastern, central, and southern Africa. The disease is transmitted by the tick Rhipicephalus appendiculatus, and caused by the protozoan Theileria parva parva, which invades host lymphocytes and promotes their clonal expansion. Importantly, indigenous cattle show tolerance to infection in ECF-endemically stable areas. Here, the putative genetic bases underlying ECF-tolerance were investigated using molecular data and epidemiological information from 823 indigenous cattle from Uganda. Vector distribution and host infection risk were estimated over the study area and subsequently tested as triggers of local adaptation by means of landscape genomics analysis. We identified 41 and seven candidate adaptive loci for tick resistance and infection tolerance, respectively. Among the genes associated with the candidate adaptive loci are PRKG1 and SLA2. PRKG1 was already described as associated with tick resistance in indigenous South African cattle, due to its role into inflammatory response. SLA2 is part of the regulatory pathways involved into lymphocytes' proliferation. Additionally, local ancestry analysis suggested the zebuine origin of the genomic region candidate for tick resistance.

RevDate: 2018-11-22

Ollivier M, Tresset A, Frantz LAF, et al (2018)

Dogs accompanied humans during the Neolithic expansion into Europe.

Biology letters, 14(10): pii:rsbl.2018.0286.

Near Eastern Neolithic farmers introduced several species of domestic plants and animals as they dispersed into Europe. Dogs were the only domestic species present in both Europe and the Near East prior to the Neolithic. Here, we assessed whether early Near Eastern dogs possessed a unique mitochondrial lineage that differentiated them from Mesolithic European populations. We then analysed mitochondrial DNA sequences from 99 ancient European and Near Eastern dogs spanning the Upper Palaeolithic to the Bronze Age to assess if incoming farmers brought Near Eastern dogs with them, or instead primarily adopted indigenous European dogs after they arrived. Our results show that European pre-Neolithic dogs all possessed the mitochondrial haplogroup C, and that the Neolithic and Post-Neolithic dogs associated with farmers from Southeastern Europe mainly possessed haplogroup D. Thus, the appearance of haplogroup D most probably resulted from the dissemination of dogs from the Near East into Europe. In Western and Northern Europe, the turnover is incomplete and haplogroup C persists well into the Chalcolithic at least. These results suggest that dogs were an integral component of the Neolithic farming package and a mitochondrial lineage associated with the Near East was introduced into Europe alongside pigs, cows, sheep and goats. It got diluted into the native dog population when reaching the Western and Northern margins of Europe.

RevDate: 2018-10-23

Thomson V, Wiewel A, Chinen A, et al (2018)

A perspective for resolving the systematics of Rattus, the vertebrates with the most influence on human welfare.

Zootaxa, 4459(3):431-452 pii:zootaxa.4459.3.2.

The murid rodent genus Rattus Fischer 1803 contains several species that are responsible for massive loss of crops and food, extinction of other species and the spread of zoonotic diseases to humans, as well as a laboratory species used to answer important questions in physiology, immunology, pharmacology, toxicology, nutrition, behaviour and learning. Despite the well-known significant impacts of Rattus, a definitive evolutionary based systematic framework for the genus is not yet available. The past 75 years have seen more dramatic changes in membership of Rattus than in almost any other genus of mammals. In fact, the Rattus genus has been a receptacle for any generalised Old World murine that lacked morphological specialisation and at one point, has included more than 560 species and/or subspecies, spread across Eurasia, Africa and the Australo-Papuan region. The dissolution of Rattus is ongoing as many of its constituent species and many genera of Rattini remain unsampled in any molecular study. To address this sampling limitation, we sequenced the mitochondrial cytochrome b (cytb) gene and examined phylogenetic relationships using both Bayesian and Maximum Likelihood algorithms for an expanded set of taxa within Rattus and among closely related genera. Here we place previously unsampled taxa in a phylogenetic context for the first time, including R. burrus, R. hoogerwerfi, R. lugens, and R. mindorensis within the Asian Rattus group, R. facetus within the Australo-Papuan Rattus radiation, and the undescribed 'Bisa Rat' described by Flannery as sister to the recently described genus Halmaheramys. We also present an exploratory foray into the wider topic of Rattus phylogenetics and propose that a reorganisation of the Rattus genus should require that it be a monophyletic group, include at least the type species R. norvegicus and R. rattus (plus their close allies); and exclude the Bandicota/Nesokia clade and other such specialised genera.

RevDate: 2018-10-23

Vences M, Hildenbrand A, Warmuth KM, et al (2018)

A new riparian Mantidactylus (Brygoomantis) frog from the Tsaratanana and Manongarivo Massifs in northern Madagascar.

Zootaxa, 4486(4):575-588 pii:zootaxa.4486.4.10.

The subgenus Brygoomantis in the Madagascar-endemic genus Mantidactylus contains 12 nominal species but is in urgent need of taxonomic revision as many additional, genetically divergent but undescribed candidate species have been identified. We here take a first step towards a better resolution of this group by describing a new species, Mantidactylus schulzi sp. nov., occurring at the Tsaratanana and Manongarivo Massifs, differentiated in genetic, bioacoustic and sometimes morphological characters from its closest relatives. We show that upon detailed study, most species in Brygoomantis can be delimited by concordant differentiation of mitochondrial and nuclear DNA, and by bioacoustic and morphological differences. We flag this group of morphologically similar frogs as a test case where molecular data on historical type specimens by ancient DNA methods might be needed to reach a satisfying clarification of taxonomy and nomenclature. However, the status of the new species M. schulzi is not in doubt as it is morphologically distinct from most historical type specimens, and microendemic to a region in northern Madagascar from where no earlier names exist.

RevDate: 2018-11-02

Herrando-Pérez S, Ferri-Yáñez F, Monasterio C, et al (2018)

Intraspecific variation in lizard heat tolerance alters estimates of climate impact.

The Journal of animal ecology [Epub ahead of print].

Research addressing the effects of global warming on the distribution and persistence of species generally assumes that population variation in thermal tolerance is spatially constant or overridden by interspecific variation. Typically, this rationale is implicit in sourcing one critical thermal maximum (CTmax) population estimate per species to model spatiotemporal cross-taxa variation in heat tolerance. Theory suggests that such an approach could result in biased or imprecise estimates and forecasts of impact from climate warming, but limited empirical evidence in support of those expectations exists. We experimentally quantify the magnitude of intraspecific variation in CTmax among lizard populations, and the extent to which incorporating such variability can alter estimates of climate impact through a biophysical model. To do so, we measured CTmax from 59 populations of 15 Iberian lizard species (304 individuals). The overall median CTmax across all individuals from all species was 42.8°C and ranged from 40.5 to 48.3°C, with species medians decreasing through xeric, climate-generalist and mesic taxa. We found strong statistical support for intraspecific differentiation in CTmax by up to a median of 3°C among populations. We show that annual restricted activity (operative temperature > CTmax) over the Iberian distribution of our study species differs by a median of >80 hr per 25-km2 grid cell based on different population-level CTmax estimates. This discrepancy leads to predictions of spatial variation in annual restricted activity to change by more than 20 days for six of the study species. Considering that during restriction periods, reptiles should be unable to feed and reproduce, current projections of climate-change impacts on the fitness of ectotherm fauna could be under- or over-estimated depending on which population is chosen to represent the physiological spectra of the species in question. Mapping heat tolerance over the full geographical ranges of single species is thus critical to address cross-taxa patterns and drivers of heat tolerance in a biologically comprehensive way.

RevDate: 2018-11-14

Fernandes DM, Strapagiel D, Borówka P, et al (2018)

A genomic Neolithic time transect of hunter-farmer admixture in central Poland.

Scientific reports, 8(1):14879 pii:10.1038/s41598-018-33067-w.

Ancient DNA genome-wide analyses of Neolithic individuals from central and southern Europe indicate an overall population turnover pattern in which migrating farmers from Anatolia and the Near East largely replaced autochthonous Mesolithic hunter-gatherers. However, the genetic history of the Neolithic transition in areas lying north of the European Neolithic core region involved different levels of admixture with hunter-gatherers. Here we analyse genome-wide data of 17 individuals spanning from the Middle Neolithic to the Early Bronze Age (4300-1900 BCE) in order to assess the Neolithic transition in north-central Poland, and the local impacts of hunter-farmer contacts and Late Neolithic steppe migrations. We evaluate the influence of these on local populations and assess if and how they change through time, reporting evidence of recurrent hunter-farmer admixture over three millennia, and the co-existence of unadmixed hunter-gatherers as late as 4300 BCE. During the Late Neolithic we report the appearance of steppe ancestry, but on a lesser scale than previously described for other central European regions, with evidence of stronger affinities to hunter-gatherers than to steppe pastoralists. These results help understand the Neolithic palaeogenomics of another central European area, Kuyavia, and highlight the complexity of population interactions during those times.

RevDate: 2018-11-16

Metspalu M, Mondal M, G Chaubey (2018)

The genetic makings of South Asia.

Current opinion in genetics & development, 53:128-133 pii:S0959-437X(17)30175-2 [Epub ahead of print].

South Asia is home for more than a billion people culturally structured into innumerable groups practicing different levels of endogamy. Linguistically South Asia is broadly characterized by four major language families which has served as access way for disentangling the genetic makings of South Asia. In this review we shall give brief account on the recent developments in the field. Advances are made in two fronts simultaneously. Whole genome characterisation of many extant South Asians paint the picture of the genetic diversity and its implications to health-care. On the other hand ancient DNA studies, which are finally reaching South Asia, provide new incites to the demographic history of the subcontinent. Before the spread of agriculture, South Asia was likely inhabited by hunter-gatherer groups deriving much of their ancestry from a population that split from the rest of humanity soon after expanding from Africa. Early Iranian agriculturalists mixing with these local hunter-gatherers probably formed the population that flourished during the blossoming of the Indus Valley Civilisation. Further admixture with the still persisting HG groups and population(s) from the Eurasian Steppe, formed the two ancestral populations (ANI and ASI), the north-south mixing pattern of whom is known today as the 'Indian Cline'. Studies on natural selection in South Asia have so far revealed strong signals of sweeps that are shared with West Eurasians. Future studies will have to fully unlock the aDNA promise for South Asia.

RevDate: 2018-11-14

Flammer PG, Dellicour S, Preston SG, et al (2018)

Molecular archaeoparasitology identifies cultural changes in the Medieval Hanseatic trading centre of Lübeck.

Proceedings. Biological sciences, 285(1888): pii:rspb.2018.0991.

Throughout history, humans have been afflicted by parasitic worms, and eggs are readily detected in archaeological deposits. This study integrated parasitological and ancient DNA methods with a large sample set dating between Neolithic and Early Modern periods to explore the utility of molecular archaeoparasitology as a new approach to study the past. Molecular analyses provided unequivocal species-level parasite identification and revealed location-specific epidemiological signatures. Faecal-oral transmitted nematodes (Ascaris lumbricoides and Trichuris trichiura) were ubiquitous across time and space. By contrast, high numbers of food-associated cestodes (Diphyllobothrium latum and Taenia saginata) were restricted to medieval Lübeck. The presence of these cestodes and changes in their prevalence at approximately 1300 CE indicate substantial alterations in diet or parasite availability. Trichuris trichiura ITS-1 sequences grouped into two clades; one ubiquitous and one restricted to medieval Lübeck and Bristol. The high sequence diversity of T.tITS-1 detected in Lübeck is consistent with its importance as a Hanseatic trading centre. Collectively, these results introduce molecular archaeoparasitology as an artefact-independent source of historical evidence.

RevDate: 2018-10-01

Mathieson S, I Mathieson (2018)

FADS1 and the timing of human adaptation to agriculture.

Molecular biology and evolution pii:5112969 [Epub ahead of print].

Variation at the FADS1/FADS2 gene cluster is functionally associated with differences in lipid metabolism and is often hypothesized to reflect adaptation to an agricultural diet. Here, we test the evidence for this relationship using both modern and ancient DNA data. We show that almost all the inhabitants of Europe carried the ancestral allele until the derived allele was introduced approximately 8,500 years ago by Early Neolithic farming populations. However, we also show that it was not under strong selection in these populations. We find that this allele, and other proposed agricultural adaptations at LCT/MCM6 and SLC22A4, were not strongly selected until much later, perhaps as late as the Bronze Age. Similarly, increased copy number variation at the salivary amylase gene AMY1 is not linked to the development of agriculture although, in this case, the putative adaptation precedes the agricultural transition. Our analysis shows that selection at the FADS locus was not tightly linked to the initial introduction of agriculture and the Neolithic transition. Further, it suggests that the strongest signals of recent human adaptation in Europe did not coincide with the Neolithic transition but with more recent changes in environment, diet or efficiency of selection due to increases in effective population size.

RevDate: 2018-10-17

Pośpiech E, Chen Y, Kukla-Bartoszek M, et al (2018)

Towards broadening Forensic DNA Phenotyping beyond pigmentation: Improving the prediction of head hair shape from DNA.

Forensic science international. Genetics, 37:241-251.

Human head hair shape, commonly classified as straight, wavy, curly or frizzy, is an attractive target for Forensic DNA Phenotyping and other applications of human appearance prediction from DNA such as in paleogenetics. The genetic knowledge underlying head hair shape variation was recently improved by the outcome of a series of genome-wide association and replication studies in a total of 26,964 subjects, highlighting 12 loci of which 8 were novel and introducing a prediction model for Europeans based on 14 SNPs. In the present study, we evaluated the capacity of DNA-based head hair shape prediction by investigating an extended set of candidate SNP predictors and by using an independent set of samples for model validation. Prediction model building was carried out in 9674 subjects (6068 from Europe, 2899 from Asia and 707 of admixed European and Asian ancestries), used previously, by considering a novel list of 90 candidate SNPs. For model validation, genotype and phenotype data were newly collected in 2415 independent subjects (2138 Europeans and 277 non-Europeans) by applying two targeted massively parallel sequencing platforms, Ion Torrent PGM and MiSeq, or the MassARRAY platform. A binomial model was developed to predict straight vs. non-straight hair based on 32 SNPs from 26 genetic loci we identified as significantly contributing to the model. This model achieved prediction accuracies, expressed as AUC, of 0.664 in Europeans and 0.789 in non-Europeans; the statistically significant difference was explained mostly by the effect of one EDAR SNP in non-Europeans. Considering sex and age, in addition to the SNPs, slightly and insignificantly increased the prediction accuracies (AUC of 0.680 and 0.800, respectively). Based on the sample size and candidate DNA markers investigated, this study provides the most robust, validated, and accurate statistical prediction models and SNP predictor marker sets currently available for predicting head hair shape from DNA, providing the next step towards broadening Forensic DNA Phenotyping beyond pigmentation traits.


RJR Experience and Expertise


Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.


Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.


Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.


Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.


While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.


Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.


Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.


Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

21454 NE 143rd Street
Woodinville, WA 98077


E-mail: RJR8222@gmail.com

Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

short personal version

Curriculum Vitae for R J Robbins

long standard version

RJR Picks from Around the Web (updated 11 MAY 2018 )