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The extinct ‘New World stilt-legged’, or NWSL, equids constitute a perplexing group of Pleistocene horses endemic to North America. Their slender distal limb bones resemble those of Asiatic asses, such as the Persian onager. Previous palaeogenetic studies, however, have suggested a closer relationship to caballine horses than to Asiatic asses. Here, we report complete mitochondrial and partial nuclear genomes from NWSL equids from across their geographic range. Although multiple NWSL equid species have been named, our palaeogenomic and morphometric analyses support the idea that there was only a single species of middle to late Pleistocene NWSL equid, and demonstrate that it falls outside of crown group Equus. We therefore propose a new genus, Haringtonhippus, for the sole species H. francisci. Our combined genomic and phenomic approach to resolving the systematics of extinct megafauna will allow for an improved understanding of the full extent of the terminal Pleistocene extinction event., eLife digest The horse family – which also includes zebras, donkeys and asses – is often featured on the pages of textbooks about evolution. All living horses belong to a group, or genus, called Equus. The fossil record shows how the ancestors of these animals evolved from dog-sized, three-toed browsers to larger, one-toed grazers. This process took around 55 million years, and many members of the horse family tree went extinct along the way. Nevertheless, the details of the horse family tree over the past 2.5 million years remain poorly understood. In North America, horses from this period – which is referred to as the Pleistocene – have been classed into two major groups: stout-legged horses and stilt-legged horses. Both groups became extinct near the end of the Pleistocene in North America, and it was not clear how they relate to one another. Based on their anatomy, many scientists suggested that stilt-legged horses were most closely related to modern-day asses living in Asia. Yet, other studies using ancient DNA placed the stilt-legged horses closer to the stout-legged horses. Heintzman et al. set out to resolve where the stilt-legged horses sit within the horse family tree by examining more ancient DNA than the previous studies. The analyses showed that the stilt-legged horses were much more distinct than previously thought. In fact, contrary to all previous findings, these animals actually belonged outside of the genus Equus. Heintzman et al. named the new genus for the stilt-legged horses Haringtonhippus, and showed that all stilt-legged horses belonged to a single species within this genus, Haringtonhippus francisci. Together these new findings provide a benchmark for reclassifying problematic fossil groups across the tree of life. A similar approach could be used to resolve the relationships in other problematic groups of Pleistocene animals, such as mammoths and bison. This would give scientists a more nuanced understanding of evolution and extinction during this period.

here is the tendency to assume that endangered species have been both genetically and demographically healthier in the past, so that any genetic erosion observed today was caused by their recent decline. The Iberian lynx (Lynx pardinus) suffered a dramatic and continuous decline during the 20th century, and now shows extremely low genome- and species-wide genetic diversity among other signs of genomic erosion. We analyze ancient (N = 10), historical (N = 245), and contemporary (N = 172) samples with microsatellite and mitogenome data to reconstruct the species' demography and investigate patterns of genetic variation across space and time. Iberian lynx populations transitioned from low but significantly higher genetic diversity than today and shallow geographical differentiation millennia ago, through a structured metapopulation with varying levels of diversity during the last centuries, to two extremely genetically depauperate and differentiated remnant populations by 2002. The historical subpopulations show varying extents of genetic drift in relation to their recent size and time in isolation, but these do not predict whether the populations persisted or went finally extinct. In conclusion, current genetic patterns were mainly shaped by genetic drift, supporting the current admixture of the two genetic pools and calling for a comprehensive genetic management of the ongoing conservation program. This study illustrates how a retrospective analysis of demographic and genetic patterns of endangered species can shed light onto their evolutionary history and this, in turn, can inform conservation actions., This research was funded by the Spanish Dirección General de Investigación Científica y Técnica, through projects CGL2006-10853/BOS, CGL2010-21540/BOS, and CGL2013-47755-P of the Spanish Ministerio de Ciencia e Innovación (MICINN) to J.A.G., and by the Fundación BBVA through a project on ancient lynx genetics to M.D. M.C. and E.M. received a JAE predoctoral grant from CSIC (Spanish National Research Council), M.L.P. was supported by PhD contracts from Programa Internacional de Becas “La Caixa-Severo Ochoa.” J.N. received financial support through projects HAR2014-55131 from the Ministerio de Ciencia e Innovación (MICINN) and SGR2014-108 from Generalitat de Catalunya.

We report here a new discovery of a cave bear left metatarsal 3 from Rochedane, an archaeological site near Montbeliard (French Jura) that yielded only Lateglacial and Holocene material, with no evidence of pre-LGM deposits, a context that made this bone a possible candidate for being a post-LGM cave bear in western Europe. To test this hypothesis, this bone was analyzed for mitochondrial DNA, which confirmed its attribution to cave bear of the Ursus spelaeus lineage, and a direct radiocarbon AMS dating on well preserved collagen (%C, %N and C/N well in the range of fresh collagen) yielded an age of 23,900 +110 -100 BP (28,730-28,500 cal BP, one sigma range). Its carbon and nitrogen isotopic values were similar to those of slightly older cave bears from the Swabian Jura, around 300 km to the East, suggesting that the ecological preferences of cave bears remained unchanged until the extirpation of this species in western Europe. Interestingly, the genetic type U. spelaeus was replaced by Ursus ingressus around 28,000 C-14 BP in the Swabian Jura. In contrast, the older type U. spelaeus apparently persisted in France ca. 3000 years longer. Traces left on the cave bear metapodium have been left by human activity on this bone, as it was the case for older cave bear bones from the Swabian Jura. This case study shows that cave bear remains found in post-LGM sites or layers may be candidates to be late survivors of this extinct species, but without direct radiocarbon AMS dated on well-preserved collagen (demonstrated by actual chemical composition results) and ancient DNA confirmation of the species attribution, such evidence can only be considered dubious. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.

Cave bears are among the most well known extinct Pleistocene mammals. Their biogeography and taxonomy, along with the factors that led to their extinction, have been subject to long-standing controversy. Here, we reconstruct the phylogeography as well as the temporal and spatial population dynamics of cave bears across their range using mitochondrial DNA control region sequences from 77 published as well as 65 new cave bear samples, Our analyses reveal a dramatic loss of genetic diversity in cave bear populations after 30,000 years before present and provide evidence for a range decline from east to west towards the onset of the last glacial maximum. Our results also suggest that the three major haplogroups within cave bears, which may correspond to distinct species, were previously more widespread, with relict populations in remote and alpine areas still harbouring haplotypes that have disappeared from most of their previous range. Applying a phylogenetic dating approach, we estimated the age of the oldest of our samples, originating from the Yana River region in north-eastern Siberia, to be around 178,000 years, which confirms a previous estimate of a Middle Pleistocene age based on its stratigraphic position. Our results extend our knowledge about the evolutionary history of cave bears, but they also show that to unravel the complexities of cave bear evolution future ancient DNA studies on this Pleistocene species will need to go beyond short mitochondrial DNA fragments, including full mitochondrial genomes as well as nuclear DNA sequences.

// Mathias Stiller 1, 2, 3 , Antje Sucker 2 , Klaus Griewank 2 , Daniela Aust 4 , Gustavo Bruno Baretton 4 , Dirk Schadendorf 2 , Susanne Horn 1, 2 1 Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, D-04103 Leipzig, Germany 2 Department of Dermatology, University Hospital, West German Cancer Center, University Duisburg-Essen, and German Consortium for Translational Cancer Research (DKTK), D-45147 Essen, Germany 3 Department for Translational Skin Cancer Research, University Duisburg-Essen, and German Consortium for Translational Cancer Research (DKTK), D-45141 Essen, Germany 4 Departments of Surgery and Pathology, Technical University Dresden, D-01307 Dresden, Germany Correspondence to: Susanne Horn, email: Susanne.Horn@uk-essen.de Mathias Stiller, email: m.stiller@dkfz-heidelberg.de Keywords: high-throughput sequencing, library preparation, formalin-fixed paraffin embedded (FFPE) tissue, cancer, whole exome sequencing Received: April 27, 2016 Accepted: June 30, 2016 Published: July 24, 2016 ABSTRACT DNA derived from formalin-fixed and paraffin-embedded (FFPE) tissue has been a challenge to large-scale genomic sequencing, due to its low quality and quantities. Improved techniques enabling the genome-wide analysis of FFPE material would be of great value, both from a research and clinical perspective. Comparing a single-strand DNA library preparation method originally developed for ancient DNA to conventional protocols using double-stranded DNA derived from FFPE material we obtain on average 900-fold more library molecules and improved sequence complexity from as little as 5 ng input DNA. FFPE DNA is highly fragmented, usually below 100bp, and up to 60% of reads start after or end prior to adenine residues, suggesting that crosslinks predominate at adenine residues. Similar to ancient DNA, C > T substitutions are slightly increased with maximum rates up to 3% at the ends of molecules. In whole exome sequencing of single-strand libraries from lung, breast, colorectal, prostate and skin cancers we identify known cancer mutations. In summary, we show that single-strand library preparation enables genomic sequencing, even from low amounts of degraded FFPE DNA. This method provides a clear advantage both in research and clinical settings, where FFPE material (e.g. from biopsies) often is the only source of DNA available. Improving the genetic characterization that can be performed on conventional archived FFPE tissue, the single-strand library preparation allows scarce samples to be used in personalized medicine and enables larger sample sizes in future sequencing studies.

The causes of the late Pleistocene megafaunal extinctions are still enigmatic. Although the fossil record can provide approximations for when a species went extinct, the timing of its disappearance alone cannot resolve the causes and mode of the decline preceding its extinction. However, ancient DNA analyses can reveal population size changes over time and narrow down potential causes of extinction. Here, we present an ancient DNA study comparing late Pleistocene population dynamics of two closely related species, cave and brown bears. We found that the decline of cave bears started approximately 25,000 years before their extinction, whereas brown bear population size remained constant. We conclude that neither the effects of climate change nor human hunting alone can be responsible for the decline of the cave bear and suggest that a complex of factors including human competition for cave sites lead to the cave bear's extinction.

Using multivariate techniques, several skulls of fossil large canids from sites in Belgium, Ukraine and Russia were examined to look for possible evidence of the presence of Palaeolithic dogs. Reference groups constituted of prehistoric dogs, and recent wolves and dogs. The fossil large canid from Goyet (Belgium), dated at c. 31,700 BP is clearly different from the recent wolves, resembling most closely the prehistoric dogs. Thus it is identified as a Palaeolithic dog, suggesting that dog domestication had already started during the Aurignacian. The Epigravettian Mezin 5490 (Ukraine) and Mezhirich (Ukraine) skulls are also identified as being Palaeolithic dogs. Selected Belgian specimens were analyzed for mtDNA and stable isotopes. All fossil samples yielded unique DNA sequences, indicating that the ancient Belgian large canids carried a substantial amount of genetic diversity. Furthermore, there is little evidence for phylogeographic structure in the Pleistocene large canids, as they do not form a homogenous genetic group. Although considerable variation occurs in the fossil canid isotope signatures between sites, the Belgian fossil large canids preyed in general on horse and large bovids.

The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy’s zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further characterize the complete mitochondrial genomes of three extinct equid lineages (the New World stilt-legged horses, NWSLH; the subgenus Sussemionus; and the Quagga, Equus quagga quagga). Comparisons with extant taxa confirm the NWSLH as being part of the caballines, and the Quagga and Plains zebras as being conspecific. However, the evolutionary relationships among the non-caballine lineages, including the now-extinct subgenus Sussemionus, remain unresolved, most likely due to extremely rapid radiation within this group. The closest living outgroups (rhinos and tapirs) were found to be too phylogenetically distant to calibrate reliable molecular clocks. Additional mitochondrial genome sequence data, including radiocarbon dated ancient equids, will be required before revisiting the exact timing of the lineage radiation leading up to modern equids, which for now were found to have possibly shared a common ancestor as far as up to 4 Million years ago (Mya).

BackgroundSecond-generation sequencing technologies have revolutionized our ability to recover genetic information from the past, allowing the characterization of the first complete genomes from past individuals and extinct species. Recently, third generation Helicos sequencing platforms, which perform true Single-Molecule DNA Sequencing (tSMS), have shown great potential for sequencing DNA molecules from Pleistocene fossils. Here, we aim at improving even further the performance of tSMS for ancient DNA by testing two novel tSMS template preparation methods for Pleistocene bone fossils, namely oligonucleotide spiking and treatment with DNA phosphatase.ResultsWe found that a significantly larger fraction of the horse genome could be covered following oligonucleotide spiking however not reproducibly and at the cost of extra post-sequencing filtering procedures and skewed %GC content. In contrast, we showed that treating ancient DNA extracts with DNA phosphatase improved the amount of endogenous sequence information recovered per sequencing channel by up to 3.3-fold, while still providing molecular signatures of endogenous ancient DNA damage, including cytosine deamination and fragmentation by depurination. Additionally, we confirmed the existence of molecular preservation niches in large bone crystals from which DNA could be preferentially extracted.ConclusionsWe propose DNA phosphatase treatment as a mechanism to increase sequence coverage of ancient genomes when using Helicos tSMS as a sequencing platform. Together with mild denaturation temperatures that favor access to endogenous ancient templates over modern DNA contaminants, this simple preparation procedure can improve overall Helicos tSMS performance when damaged DNA templates are targeted.

Multiplex PCR allows the simultaneous amplification of up to dozens of target fragments in a single PCR. It is therefore a powerful tool to obtain many kilobases of continuous sequence from minute amounts of ancient DNA (aDNA), which usually must be amplified in multiple short and overlapping fragments. Because significantly less template is required compared to amplifying each fragment separately, multiplex PCR is particularly beneficial when the fossil material itself, or access to the fossil material, is limited. The recently refined two-step multiplex PCR protocol consists of a first-step reaction (the actual multiplex PCR) that then acts as the template for the second-step PCR. During the second step, nested primers are used in individual amplification reactions. Although the same set of primers can be used in both steps, using a nested set in the second step adds an additional level of selectivity and specificity, minimizing PCR artifacts. This is particularly important when complex mixtures of template DNA, such as aDNA extracts, are amplified.

PCR amplification of DNA is routine in modern molecular biology. However, the application of PCR to ancient DNA (aDNA) experiments often requires significant modification to standard protocols. The degraded nature of most aDNA fragments requires targeting shorter fragments, performing replicate amplifications, incorporating multiple negative controls, combating PCR inhibition, using specific DNA polymerases to deal with damaged bases, working in a separate aDNA facility, and modifying the PCR recipe to deal with damaged and low copy-number target DNA. In this chapter, we describe how and why these procedures are implemented, discuss aDNA-specific troubleshooting methodology, and suggest modifications to commercial cloning and sequencing procedures to reduce the expense of PCR product cloning.

Here I describe the use of a recently developed technique for targeted high-throughput sequencing of highly degraded DNA by direct multiplex PCR sequencing (DMPS) that was used to amplify 31 near-complete mitochondrial genomes of the extinct cave bear (Ursus spelaeus). DMPS couples multiplex PCR with the generation of barcoded sequencing libraries to be sequenced in parallel on a high-throughput sequencing platform. DMPS makes it possible to generate large amounts of targeted DNA sequence data simultaneously from multiple degraded samples such as fossil remains. In this chapter, I describe an experiment that uses DMPS with different primer sets and on both modern and ancient DNA templates.

Previous bone collagen carbon and nitrogen isotopic studies of Late Pleistocene European cave bears ( Ursus spelaeus ) have shown that these bears frequently had low nitrogen isotope values, similar to those of herbivores and indicating either unusual physiology related to hibernation or a herbivorous diet. Isotopic analysis of animal bone from the Peştera cu Oase (Cave with Bones), Romania, shows that most of its cave bears had higher nitrogen isotope values than the associated herbivores and were, therefore, omnivorous. The Oase bears are securely identified as cave bears by both their morphology and DNA sequences. Although many cave bear populations may have behaved like herbivores, the Oase isotopic data demonstrate that cave bears were capable of altering their diets to become omnivores or even carnivores. These data therefore broaden the dietary profile of U. spelaeus and raise questions about the nature of the carnivore guild in Pleistocene Europe.

Models for the development of species distribution in Europe typically invoke restriction in three temperate Mediterranean refugia during glaciations, from where recolonization of central and northern Europe occurred. The brown bear, Ursus arctos, is one of the taxa from which this model is derived. Sequence data generated from brown bear fossils show a complex phylogeographical history for western European populations. Long-term isolation in separate refugia is not required to explain our data when considering the palaeontological distribution of brown bears. We propose continuous gene flow across southern Europe, from which brown bear populations expanded after the last glaciation.