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  - 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  -