Ancient DNA

Cross-linked DNA extracted from the 4,000-year-old liver of the ancient Egyptian priest Nekht-Ankh

Ancient DNA (aDNA) is DNA isolated from ancient sources (typically specimens, but also environmental DNA).[1][2] Due to degradation processes (including cross-linking, deamination and fragmentation)[3] ancient DNA is more degraded in comparison with contemporary genetic material.[4] Genetic material has been recovered from paleo/archaeological and historical skeletal material, mummified tissues, archival collections of non-frozen medical specimens, preserved plant remains, ice and from permafrost cores, marine and lake sediments and excavation dirt.

Even under the best preservation conditions, there is an upper boundary of 0.4–1.5 million years for a sample to contain sufficient DNA for sequencing technologies.[5] The oldest DNA sequenced from physical specimens are from mammoth molars in Siberia over 1 million years old.[6] In 2022, two-million year old genetic material was recovered from sediments in Greenland, and is currently considered the oldest DNA discovered so far.[7][8]

  1. ^ Pevsner J (2015). Bioinformatics and Functional Genomics (3rd ed.). Wiley-Blackwell. ISBN 978-1118581780.
  2. ^ Jones M (2016). Unlocking the Past: How Archaeologists Are Rewriting Human History with Ancient DNA. Arcade. ISBN 978-1628724479.
  3. ^ Anderson LA (May 2023). "A chemical framework for the preservation of fossil vertebrate cells and soft tissues". Earth-Science Reviews. 240: 104367. Bibcode:2023ESRv..24004367A. doi:10.1016/j.earscirev.2023.104367. S2CID 257326012.
  4. ^ Cite error: The named reference Allentoft, M.E. 2012 was invoked but never defined (see the help page).
  5. ^ Willerslev E, Hansen AJ, Rønn R, Brand TB, Barnes I, Wiuf C, et al. (January 2004). "Long-term persistence of bacterial DNA" (PDF). Current Biology. 14 (1): R9-10. Bibcode:2004CBio...14...R9W. doi:10.1016/j.cub.2003.12.012. PMID 14711425. S2CID 12227538.
  6. ^ van der Valk T, Pečnerová P, Díez-Del-Molino D, Bergström A, Oppenheimer J, Hartmann S, et al. (March 2021). "Million-year-old DNA sheds light on the genomic history of mammoths". Nature. 591 (7849): 265–269. Bibcode:2021Natur.591..265V. doi:10.1038/s41586-021-03224-9. PMC 7116897. PMID 33597750.
  7. ^ Cite error: The named reference NYT-20221207 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference NAT-20221207 was invoked but never defined (see the help page).