Middle Pleistocene genome calibrates a revised evolutionary history of extinct cave bears

Axel Barlow, Johanna L.A. Paijmans, Federica Alberti, Boris Gasparyan, Guy Bar-Oz, Ron Pinhasi, Irina Foronova, Andrey Y. Puzachenko, Martina Pacher, Love Dalén, Gennady Baryshnikov, Michael Hofreiter

Research output: Contribution to journalArticlepeer-review


Palaeogenomes provide the potential to study evolutionary processes in real time, but this potential is limited by our ability to recover genetic data over extended timescales.1 As a consequence, most studies so far have focused on samples of Late Pleistocene or Holocene age, which covers only a small part of the history of many clades and species. Here, we report the recovery of a low coverage palaeogenome from the petrous bone of a ∼360,000 year old cave bear from Kudaro 1 cave in the Caucasus Mountains. Analysis of this genome alongside those of several Late Pleistocene cave bears reveals widespread mito-nuclear discordance in this group. Using the time interval between Middle and Late Pleistocene cave bear genomes, we directly estimate ursid nuclear and mitochondrial substitution rates to calibrate their respective phylogenies. This reveals post-divergence mitochondrial transfer as the dominant factor explaining their mito-nuclear discordance. Interestingly, these transfer events were not accompanied by large-scale nuclear introgression. However, we do detect additional instances of nuclear admixture among other cave bear lineages, and between cave bears and brown bears, which are not associated with mitochondrial exchange. Genomic data obtained from the Middle Pleistocene cave bear petrous bone has thus facilitated a revised evolutionary history of this extinct megafaunal group. Moreover, it suggests that petrous bones may provide a means of extending both the magnitude and time depth of palaeogenome retrieval over substantial portions of the evolutionary histories of many mammalian clades.

Original languageAmerican English
Pages (from-to)1771-1779
JournalCurrent Biology
Issue number8
StatePublished - 26 Apr 2021


  • Middle Pleistocene
  • Ursus
  • ancient DNA
  • cave bear
  • evolution
  • paleogenomics

All Science Journal Classification (ASJC) codes

  • General Biochemistry,Genetics and Molecular Biology
  • General Neuroscience
  • General Agricultural and Biological Sciences


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