The Kennewick, and the Oase I

Last week was glorious for ancient DNA enthusiasts – here are some quick blurbs on findings from genomic analyses of the Kennewick man, and the Oase I individual.

Facial reconstructions of the Oase I individual (L), and the Kennewick man (R). Image courtesies: The Smithsonian Magazine  (http://thumbs.media.smithsonianmag.com//filer/51/9f/519fea8a-a215-48fe-ba09-fae09a0bb3e3/kennewick-hero.jpg__800x600_q85_crop.jpg), Dons Maps (http://donsmaps.com/romaniancaveskull.html)

Facial reconstructions of the Oase I individual (L), and the Kennewick man (R). Image courtesies: The Smithsonian Magazine (http://thumbs.media.smithsonianmag.com//filer/51/9f/519fea8a-a215-48fe-ba09-fae09a0bb3e3/kennewick-hero.jpg__800x600_q85_crop.jpg), Dons Maps (http://donsmaps.com/romaniancaveskull.html)

The ancestry and affiliations of Kennewick Man, Rasmussen et al. (2015) Nature DOI: 10.1038/nature14625

There has been much ado over the ancestry of the Kennewick Man – carbon-dating studies have dated his remains to ~8,500 ybp, morphological studies maintain distinction from Native American (Pacific Northwestern) ancestry, and teams of scientists and tribes battle on over the impending fate of the remains. Rasmussen et al. (2015) in an interesting turn of events, analyze genomic ancestry of the Kennewick man, and find clear evidence of Native American ancestry using both a PCA, and f3-statistics. Important findings of this study include: (a) rejection of Ainu/Polynesian ancestry of the Kennewick man, as suggested by morphological studies, (b) similarity in admixture proportions to Native American, particularly among claimant tribes, and (c) direct or derivative ancestry of current Native Americans from the Kennewick man. While this answers some questions about the ancestry of the Kennewick man, it also brings forth unaddressed details of ancestral admixture, and migration in Holocene Americas.

Identifying which modern Native American groups are most closely related to Kennewick Man is not possible at this time, since our comparative DNA database of modern people is limited, particularly for Native American groups in the United States.

An early modern human from Romania with a recent Neanderthal ancestor, Fu et al. (2015) Nature DOI: 10.1038/nature14558

Meanwhile, in a much more distant past, the Kennewick man’s ancestors were still diversifying out of Africa, admixing with Neanderthals around 37,000-86,000 ybp, with little knowledge of the process of admixture, or understanding of Neanderthal extinction. Fu et al. (2015) analyze ancient genomic DNA from the Oase I individual, one of the oldest modern human remains yet discovered to report 6.0% -9.4%  Neanderthal ancestry. In comparison with the Ust’-Ishim, Kostenki, and modern Chinese and European individuals, the Oase I individual contains 2-4 fold higher Neanderthal alleles. Analysis of IBD segment lengths (i.e. identical segments, unbroken by recombination) also indicates that the Neanderthal admixture occurred within 4-6 generations ancestral to the Oase I individual.

However, the absence of a clear relationship of the Oase 1 individual to later modern humans in Europe suggests that he may have been a member of an initial early modern human population that interbred with Neanderthals but did not contribute much to later European populations

References:

Rasmussen, Morten, et al. “The ancestry and affiliations of Kennewick Man.”Nature (2015). DOI: 10.1038/nature14625

Fu, Qiaomei, et al. “An early modern human from Romania with a recent Neanderthal ancestor.” Nature (2015). DOI: 10.1038/nature14558

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About Arun Sethuraman

I am a computational biologist, and I build statistical models and tools for population genetics. I am particularly interested in studying the dynamics of structured populations, genetic admixture, and ancestral demography.
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