@unpublished{HagelbergHofreiterKeyser2015, author = {Hagelberg, Erika and Hofreiter, Michael and Keyser, Christine}, title = {Ancient DNA: the first three decades}, series = {Philosophical transactions of the Royal Society of London : B, Biological sciences}, volume = {370}, journal = {Philosophical transactions of the Royal Society of London : B, Biological sciences}, number = {1660}, publisher = {Royal Society}, address = {London}, issn = {0962-8436}, doi = {10.1098/rstb.2013.0371}, pages = {6}, year = {2015}, language = {en} } @article{HofreiterPaijmansGoodchildetal.2015, author = {Hofreiter, Michael and Paijmans, Johanna L. A. and Goodchild, Helen and Speller, Camilla F. and Barlow, Axel and Gonz{\´a}lez-Fortes, Gloria M. and Thomas, Jessica A. and Ludwig, Arne and Collins, Matthew J.}, title = {The future of ancient DNA: Technical advances and conceptual shifts}, series = {Bioessays : ideas that push the boundaries}, volume = {37}, journal = {Bioessays : ideas that push the boundaries}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0265-9247}, doi = {10.1002/bies.201400160}, pages = {284 -- 293}, year = {2015}, abstract = {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.}, language = {en} } @article{ThomasCarvalhoHaileetal.2017, author = {Thomas, Jessica E. and Carvalho, Gary R. and Haile, James and Martin, Michael D. and Castruita, Jose A. Samaniego and Niemann, Jonas and Sinding, Mikkel-Holger S. and Sandoval-Velasco, Marcela and Rawlence, Nicolas J. and Fuller, Errol and Fjeldsa, Jon and Hofreiter, Michael and Stewart, John R. and Gilbert, M. Thomas P. and Knapp, Michael}, title = {An ‛Aukward' tale}, series = {Genes}, volume = {8}, journal = {Genes}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2073-4425}, doi = {10.3390/genes8060164}, pages = {164}, year = {2017}, abstract = {One hundred and seventy-three years ago, the last two Great Auks, Pinguinus impennis, ever reliably seen were killed. Their internal organs can be found in the collections of the Natural History Museum of Denmark, but the location of their skins has remained a mystery. In 1999, Great Auk expert Errol Fuller proposed a list of five potential candidate skins in museums around the world. Here we take a palaeogenomic approach to test which—if any—of Fuller's candidate skins likely belong to either of the two birds. Using mitochondrial genomes from the five candidate birds (housed in museums in Bremen, Brussels, Kiel, Los Angeles, and Oldenburg) and the organs of the last two known individuals, we partially solve the mystery that has been on Great Auk scholars' minds for generations and make new suggestions as to the whereabouts of the still-missing skin from these two birds.}, language = {en} } @article{TaronLellBarlowetal.2018, author = {Taron, Ulrike H. and Lell, Moritz and Barlow, Axel and Paijmans, Johanna L. A.}, title = {Testing of Alignment Parameters for Ancient Samples}, series = {Genes}, volume = {9}, journal = {Genes}, number = {3}, publisher = {Molecular Diversity Preservation International}, address = {Basel}, issn = {2073-4425}, doi = {10.3390/genes9030157}, pages = {1 -- 12}, year = {2018}, abstract = {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.}, language = {en} } @article{TaronLellBarlowetal.2018, author = {Taron, Ulrike H. and Lell, Moritz and Barlow, Axel and Paijmans, Johanna L. A.}, title = {Testing of Alignment Parameters for Ancient Samples}, series = {Genese}, volume = {9}, journal = {Genese}, number = {3}, publisher = {MDPI}, address = {Basel}, issn = {2073-4425}, doi = {10.3390/genes9030157}, pages = {12}, year = {2018}, abstract = {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.}, language = {en} } @article{AlbertiGonzalezPaijmansetal.2018, author = {Alberti, Federica and Gonzalez, Javier and Paijmans, Johanna L. A. and Basler, Nikolas and Preick, Michaela and Henneberger, Kirstin and Trinks, Alexandra and Rabeder, Gernot and Conard, Nicholas J. and Muenzel, Susanne C. and Joger, Ulrich and Fritsch, Guido and Hildebrandt, Thomas and Hofreiter, Michael and Barlow, Axel}, title = {Optimized DNA sampling of ancient bones using Computed Tomography scans}, series = {Molecular ecology resources}, volume = {18}, journal = {Molecular ecology resources}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {1755-098X}, doi = {10.1111/1755-0998.12911}, pages = {1196 -- 1208}, year = {2018}, abstract = {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.}, language = {en} } @article{BarlowHartmannGonzalezetal.2020, author = {Barlow, Axel and Hartmann, Stefanie and Gonzalez, Javier and Hofreiter, Michael and Paijmans, Johanna L. A.}, title = {Consensify}, series = {Genes / Molecular Diversity Preservation International}, volume = {11}, journal = {Genes / Molecular Diversity Preservation International}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2073-4425}, doi = {10.3390/genes11010050}, pages = {22}, year = {2020}, abstract = {A standard practise in palaeogenome analysis is the conversion of mapped short read data into pseudohaploid sequences, frequently by selecting a single high-quality nucleotide at random from the stack of mapped reads. This controls for biases due to differential sequencing coverage, but it does not control for differential rates and types of sequencing error, which are frequently large and variable in datasets obtained from ancient samples. These errors have the potential to distort phylogenetic and population clustering analyses, and to mislead tests of admixture using D statistics. We introduce Consensify, a method for generating pseudohaploid sequences, which controls for biases resulting from differential sequencing coverage while greatly reducing error rates. The error correction is derived directly from the data itself, without the requirement for additional genomic resources or simplifying assumptions such as contemporaneous sampling. For phylogenetic and population clustering analysis, we find that Consensify is less affected by artefacts than methods based on single read sampling. For D statistics, Consensify is more resistant to false positives and appears to be less affected by biases resulting from different laboratory protocols than other frequently used methods. Although Consensify is developed with palaeogenomic data in mind, it is applicable for any low to medium coverage short read datasets. We predict that Consensify will be a useful tool for future studies of palaeogenomes.}, language = {en} }