TY - JOUR A1 - Kehlmaier, Christian A1 - Barlow, Axel A1 - Hastings, Alexander K. A1 - Vamberger, Melita A1 - Paijmans, Johanna L. A. A1 - Steadman, David W. A1 - Albury, Nancy A. A1 - Franz, Richard A1 - Hofreiter, Michael A1 - Fritz, Uwe T1 - Tropical ancient DNA reveals relationships of the extinct bahamian giant tortoise Chelonoidis alburyorum JF - Proceedings of the Royal Society of London : Series B, Biological sciences N2 - Ancient DNA of extinct species from the Pleistocene and Holocene has provided valuable evolutionary insights. However, these are largely restricted to mammals and high latitudes because DNA preservation in warm climates is typically poor. In the tropics and subtropics, non-avian reptiles constitute a significant part of the fauna and little is known about the genetics of the many extinct reptiles from tropical islands. We have reconstructed the near-complete mitochondrial genome of an extinct giant tortoise from the Bahamas (Chelonoidis alburyorum) using an approximately 1000-year-old humerus from a water-filled sinkhole (blue hole) on Great Abaco Island. Phylogenetic and molecular clock analyses place this extinct species as closely related to Galapagos (C. niger complex) and Chaco tortoises (C. chilensis), and provide evidence for repeated overseas dispersal in this tortoise group. The ancestors of extant Chelonoidis species arrived in South America from Africa only after the opening of the Atlantic Ocean and dispersed from there to the Caribbean and the Galapagos Islands. Our results also suggest that the anoxic, thermally buffered environment of blue holes may enhance DNA preservation, and thus are opening a window for better understanding evolution and population history of extinct tropical species, which would likely still exist without human impact. KW - Bahamas KW - biogeography KW - extinction KW - palaeontology KW - phylogeny Y1 - 2017 U6 - https://doi.org/10.1098/rspb.2016.2235 SN - 0962-8452 SN - 1471-2954 VL - 284 PB - The Royal Society CY - London ER - TY - JOUR A1 - Hofreiter, Michael A1 - Paijmans, Johanna L. A. A1 - Goodchild, Helen A1 - Speller, Camilla F. A1 - Barlow, Axel A1 - González-Fortes, Gloria M. A1 - Thomas, Jessica A. A1 - Ludwig, Arne A1 - Collins, Matthew J. T1 - The future of ancient DNA: Technical advances and conceptual shifts JF - Bioessays : ideas that push the boundaries N2 - Technological innovations such as next generation sequencing and DNA hybridisation enrichment have resulted in multi-fold increases in both the quantity of ancient DNA sequence data and the time depth for DNA retrieval. To date, over 30 ancient genomes have been sequenced, moving from 0.7x coverage (mammoth) in 2008 to more than 50x coverage (Neanderthal) in 2014. Studies of rapid evolutionary changes, such as the evolution and spread of pathogens and the genetic responses of hosts, or the genetics of domestication and climatic adaptation, are developing swiftly and the importance of palaeogenomics for investigating evolutionary processes during the last million years is likely to increase considerably. However, these new datasets require new methods of data processing and analysis, as well as conceptual changes in interpreting the results. In this review we highlight important areas of future technical and conceptual progress and discuss research topics in the rapidly growing field of palaeogenomics. KW - ancient DNA KW - hybridisation capture KW - multi-locus data KW - next generation sequencing (NGS) KW - palaeogenomics KW - population genomics Y1 - 2015 U6 - https://doi.org/10.1002/bies.201400160 SN - 0265-9247 SN - 1521-1878 VL - 37 IS - 3 SP - 284 EP - 293 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Taron, Ulrike H. A1 - Lell, Moritz A1 - Barlow, Axel A1 - Paijmans, Johanna L. A. T1 - Testing of Alignment Parameters for Ancient Samples BT - Evaluating and Optimizing Mapping Parameters for Ancient Samples Using the TAPAS Tool JF - Genes N2 - High-throughput sequence data retrieved from ancient or other degraded samples has led to unprecedented insights into the evolutionary history of many species, but the analysis of such sequences also poses specific computational challenges. The most commonly used approach involves mapping sequence reads to a reference genome. However, this process becomes increasingly challenging with an elevated genetic distance between target and reference or with the presence of contaminant sequences with high sequence similarity to the target species. The evaluation and testing of mapping efficiency and stringency are thus paramount for the reliable identification and analysis of ancient sequences. In this paper, we present ‘TAPAS’, (Testing of Alignment Parameters for Ancient Samples), a computational tool that enables the systematic testing of mapping tools for ancient data by simulating sequence data reflecting the properties of an ancient dataset and performing test runs using the mapping software and parameter settings of interest. We showcase TAPAS by using it to assess and improve mapping strategy for a degraded sample from a banded linsang (Prionodon linsang), for which no closely related reference is currently available. This enables a 1.8-fold increase of the number of mapped reads without sacrificing mapping specificity. The increase of mapped reads effectively reduces the need for additional sequencing, thus making more economical use of time, resources, and sample material. KW - ancient DNA KW - short-read mapping KW - palaeogenomics KW - alignment sensitivity / specificity Y1 - 2018 U6 - https://doi.org/10.3390/genes9030157 SN - 2073-4425 VL - 9 IS - 3 SP - 1 EP - 12 PB - Molecular Diversity Preservation International CY - Basel ER - TY - JOUR A1 - Taron, Ulrike H. A1 - Lell, Moritz A1 - Barlow, Axel A1 - Paijmans, Johanna L. A. T1 - Testing of Alignment Parameters for Ancient Samples BT - Evaluating and Optimizing Mapping Parameters for Ancient Samples Using the TAPAS Tool JF - Genese N2 - High-throughput sequence data retrieved from ancient or other degraded samples has led to unprecedented insights into the evolutionary history of many species, but the analysis of such sequences also poses specific computational challenges. The most commonly used approach involves mapping sequence reads to a reference genome. However, this process becomes increasingly challenging with an elevated genetic distance between target and reference or with the presence of contaminant sequences with high sequence similarity to the target species. The evaluation and testing of mapping efficiency and stringency are thus paramount for the reliable identification and analysis of ancient sequences. In this paper, we present ‘TAPAS’, (Testing of Alignment Parameters for Ancient Samples), a computational tool that enables the systematic testing of mapping tools for ancient data by simulating sequence data reflecting the properties of an ancient dataset and performing test runs using the mapping software and parameter settings of interest. We showcase TAPAS by using it to assess and improve mapping strategy for a degraded sample from a banded linsang (Prionodon linsang), for which no closely related reference is currently available. This enables a 1.8-fold increase of the number of mapped reads without sacrificing mapping specificity. The increase of mapped reads effectively reduces the need for additional sequencing, thus making more economical use of time, resources, and sample material. KW - ancient DNA KW - short-read mapping KW - palaeogenomics KW - paleogenomics KW - alignment sensitivity/specificity Y1 - 2018 U6 - https://doi.org/10.3390/genes9030157 SN - 2073-4425 VL - 9 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - Agne, Stefanie A1 - Naylor, Gavin J. P. A1 - Preick, Michaela A1 - Yang, Lei A1 - Thiel, Ralf A1 - Weigmann, Simon A1 - Paijmans, Johanna L. A. A1 - Barlow, Axel A1 - Hofreiter, Michael A1 - Straube, Nicolas T1 - Taxonomic identification of two poorly known lantern shark species based on mitochondrial DNA from wet-collection paratypes JF - Frontiers in Ecology and Evolution N2 - Etmopteridae (lantern sharks) is the most species-rich family of sharks, comprising more than 50 species. Many species are described from few individuals, and re-collection of specimens is often hindered by the remoteness of their sampling sites. For taxonomic studies, comparative morphological analysis of type specimens housed in natural history collections has been the main source of evidence. In contrast, DNA sequence information has rarely been used. Most lantern shark collection specimens, including the types, were formalin fixed before long-term storage in ethanol solutions. The DNA damage caused by both fixation and preservation of specimens has excluded these specimens from DNA sequence-based phylogenetic analyses so far. However, recent advances in the field of ancient DNA have allowed recovery of wet-collection specimen DNA sequence data. Here we analyse archival mitochondrial DNA sequences, obtained using ancient DNA approaches, of two wet-collection lantern shark paratype specimens, namely Etmopterus litvinovi and E. pycnolepis, for which the type series represent the only known individuals. Target capture of mitochondrial markers from single-stranded DNA libraries allows for phylogenetic placement of both species. Our results suggest synonymy of E. benchleyi with E. litvinovi but support the species status of E. pycnolepis. This revised taxonomy is helpful for future conservation and management efforts, as our results indicate a larger distribution range of E. litvinovi. This study further demonstrates the importance of wet-collection type specimens as genetic resource for taxonomic research. KW - type specimens KW - Etmopterus litvinovi KW - Etmopterus pycnolepis KW - deep-sea KW - sharks KW - archival DNA Y1 - 2022 U6 - https://doi.org/10.3389/fevo.2022.910009 SN - 2296-701X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Beck, Samantha V. A1 - Carvalho, Gary R. A1 - Barlow, Axel A1 - Ruber, Lukas A1 - Tan, Heok Hui A1 - Nugroho, Estu A1 - Wowor, Daisy A1 - Nor, Siti Azizah Mohd A1 - Herder, Fabian A1 - Muchlisin, Zainal A. A1 - de Bruyn, Mark T1 - Plio-Pleistocene phylogeography of the Southeast Asian Blue Panchax killifish, Aplocheilus panchax JF - PLoS one Y1 - 2017 U6 - https://doi.org/10.1371/journal.pone.0179557 SN - 1932-6203 VL - 12 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Barlow, Axel A1 - Cahill, James A. A1 - Hartmann, Stefanie A1 - Theunert, Christoph A1 - Xenikoudakis, Georgios A1 - Gonzalez-Fortes, Gloria M. A1 - Paijmans, Johanna L. A. A1 - Rabeder, Gernot A1 - Frischauf, Christine A1 - Garcia-Vazquez, Ana A1 - Murtskhvaladze, Marine A1 - Saarma, Urmas A1 - Anijalg, Peeter A1 - Skrbinsek, Tomaz A1 - Bertorelle, Giorgio A1 - Gasparian, Boris A1 - Bar-Oz, Guy A1 - Pinhasi, Ron A1 - Slatkin, Montgomery A1 - Dalen, Love A1 - Shapiro, Beth A1 - Hofreiter, Michael T1 - Partial genomic survival of cave bears in living brown bears JF - Nature Ecology & Evolution N2 - Although many large mammal species went extinct at the end of the Pleistocene epoch, their DNA may persist due to past episodes of interspecies admixture. However, direct empirical evidence of the persistence of ancient alleles remains scarce. Here, we present multifold coverage genomic data from four Late Pleistocene cave bears (Ursus spelaeus complex) and show that cave bears hybridized with brown bears (Ursus arctos) during the Pleistocene. We develop an approach to assess both the directionality and relative timing of gene flow. We find that segments of cave bear DNA still persist in the genomes of living brown bears, with cave bears contributing 0.9 to 2.4% of the genomes of all brown bears investigated. Our results show that even though extinction is typically considered as absolute, following admixture, fragments of the gene pool of extinct species can survive for tens of thousands of years in the genomes of extant recipient species. Y1 - 2018 U6 - https://doi.org/10.1038/s41559-018-0654-8 SN - 2397-334X VL - 2 IS - 10 SP - 1563 EP - 1570 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Sheng, Gui-Lian A1 - Basler, Nikolas A1 - Ji, Xue-Ping A1 - Paijmans, Johanna L. A. A1 - Alberti, Federica A1 - Preick, Michaela A1 - Hartmann, Stefanie A1 - Westbury, Michael V. A1 - Yuan, Jun-Xia A1 - Jablonski, Nina G. A1 - Xenikoudakis, Georgios A1 - Hou, Xin-Dong A1 - Xiao, Bo A1 - Liu, Jian-Hui A1 - Hofreiter, Michael A1 - Lai, Xu-Long A1 - Barlow, Axel T1 - Paleogenome reveals genetic contribution of extinct giant panda to extant populations JF - Current biology N2 - Historically, the giant panda was widely distributed from northern China to southwestern Asia [1]. As a result of range contraction and fragmentation, extant individuals are currently restricted to fragmented mountain ranges on the eastern margin of the Qinghai-Tibet plateau, where they are distributed among three major population clusters [2]. However, little is known about the genetic consequences of this dramatic range contraction. For example, were regions where giant pandas previously existed occupied by ancestors of present-day populations, or were these regions occupied by genetically distinct populations that are now extinct? If so, is there any contribution of these extinct populations to the genomes of giant pandas living today? To investigate these questions, we sequenced the nuclear genome of an similar to 5,000-year-old giant panda from Jiangdongshan, Teng-chong County in Yunnan Province, China. We find that this individual represents a genetically distinct population that diverged prior to the diversification of modern giant panda populations. We find evidence of differential admixture with this ancient population among modern individuals originating from different populations as well as within the same population. We also find evidence for directional gene flow, which transferred alleles from the ancient population into the modern giant panda lineages. A variable proportion of the genomes of extant individuals is therefore likely derived from the ancient population represented by our sequenced individual. Although extant giant panda populations retain reasonable genetic diversity, our results suggest that this represents only part of the genetic diversity this species harbored prior to its recent range contractions. Y1 - 2019 U6 - https://doi.org/10.1016/j.cub.2019.04.021 SN - 0960-9822 SN - 1879-0445 VL - 29 IS - 10 SP - 1695 EP - 1700 PB - Cell Press CY - Cambridge ER - TY - JOUR A1 - Alberti, Federica A1 - Gonzalez, Javier A1 - Paijmans, Johanna L. A. A1 - Basler, Nikolas A1 - Preick, Michaela A1 - Henneberger, Kirstin A1 - Trinks, Alexandra A1 - Rabeder, Gernot A1 - Conard, Nicholas J. A1 - Muenzel, Susanne C. A1 - Joger, Ulrich A1 - Fritsch, Guido A1 - Hildebrandt, Thomas A1 - Hofreiter, Michael A1 - Barlow, Axel T1 - Optimized DNA sampling of ancient bones using Computed Tomography scans JF - Molecular ecology resources N2 - The prevalence of contaminant microbial DNA in ancient bone samples represents the principal limiting factor for palaeogenomic studies, as it may comprise more than 99% of DNA molecules obtained. Efforts to exclude or reduce this contaminant fraction have been numerous but also variable in their success. Here, we present a simple but highly effective method to increase the relative proportion of endogenous molecules obtained from ancient bones. Using computed tomography (CT) scanning, we identify the densest region of a bone as optimal for sampling. This approach accurately identifies the densest internal regions of petrous bones, which are known to be a source of high-purity ancient DNA. For ancient long bones, CT scans reveal a high-density outermost layer, which has been routinely removed and discarded prior to DNA extraction. For almost all long bones investigated, we find that targeted sampling of this outermost layer provides an increase in endogenous DNA content over that obtained from softer, trabecular bone. This targeted sampling can produce as much as 50-fold increase in the proportion of endogenous DNA, providing a directly proportional reduction in sequencing costs for shotgun sequencing experiments. The observed increases in endogenous DNA proportion are not associated with any reduction in absolute endogenous molecule recovery. Although sampling the outermost layer can result in higher levels of human contamination, some bones were found to have more contamination associated with the internal bone structures. Our method is highly consistent, reproducible and applicable across a wide range of bone types, ages and species. We predict that this discovery will greatly extend the potential to study ancient populations and species in the genomics era. KW - ancient DNA KW - computer tomography KW - palaeogenomics KW - paleogenetics KW - petrous bone Y1 - 2018 U6 - https://doi.org/10.1111/1755-0998.12911 SN - 1755-098X SN - 1755-0998 VL - 18 IS - 6 SP - 1196 EP - 1208 PB - Wiley CY - Hoboken ER - TY - GEN A1 - Barlow, Axel A1 - Sheng, Gui-Lian A1 - Lai, Xu-Long A1 - Hofreiter, Michael A1 - Paijmans, Johanna L. A. T1 - Once lost, twice found: Combined analysis of ancient giant panda sequences characterises extinct clade T2 - Journal of biogeography Y1 - 2018 U6 - https://doi.org/10.1111/jbi.13486 SN - 0305-0270 SN - 1365-2699 VL - 46 IS - 1 SP - 251 EP - 253 PB - Wiley CY - Hoboken ER -