Ancient DNA From Kennewick Man Confirms Native American Founder Population Membership

A new study by Rasmussen, et al., entitled "The ancestry and affiliations of Kennewick Man", in the journal Nature was published online today (open access).  Much of the information in the study was available in advance of publication, six months ago.

It finds that ancient DNA from Kennewick Man confirms his membership in the founding population of Native Americans (as opposed to Arctic or Na-Dene populations of Native Americans), despite physical anthropology measurements suggesting an East Eurasian or Polynesian ancestry.  The abstract is as follows:

Kennewick Man, referred to as the Ancient One by Native Americans, is a male human skeleton discovered in Washington state (USA) in 1996 and initially radiocarbon-dated to 8,340–9,200 calibrated years before present (BP). His population affinities have been the subject of scientific debate and legal controversy. 

Based on an initial study of cranial morphology it was asserted that Kennewick Man was neither Native American nor closely related to the claimant Plateau tribes of the Pacific Northwest, who claimed ancestral relationship and requested repatriation under the Native American Graves Protection and Repatriation Act (NAGPRA). The morphological analysis was important to judicial decisions that Kennewick Man was not Native American and that therefore NAGPRA did not apply. Instead of repatriation, additional studies of the remains were permitted. Subsequent craniometric analysis affirmed Kennewick Man to be more closely related to circumpacific groups such as the Ainu and Polynesians than he is to modern Native Americans. 

In order to resolve Kennewick Man’s ancestry and affiliations, we have sequenced his genome to ~1× coverage and compared it to worldwide genomic data including the Ainu and Polynesians. We find that Kennewick Man is closer to modern Native Americans than to any other population worldwide. 

Among the Native American groups for whom genome-wide data are available for comparison, several seem to be descended from a population closely related to that of Kennewick Man, including the Confederated Tribes of the Colville Reservation (Colville), one of the five tribes claiming Kennewick Man. 

We revisit the cranial analyses and find that, as opposed to genomic-wide comparisons, it is not possible on that basis to affiliate Kennewick Man to specific contemporary groups. We therefore conclude based on genetic comparisons that Kennewick Man shows continuity with Native North Americans over at least the last eight millennia.

In short, Kennewick Man's ancient DNA largely confirms the dominant paradigm of the initial human settlement of the Americas, as have other ancient DNA samples from the Americas.

This said, many Native American populations have diverged genetically over time from Kennewick man who is closest to the non-Na-Dene modern Native American populations in the general vicinity of the Pacific Northwest.  Native American ancestry components that are only a part of Kennewick man's DNA are dominant components of many modern Native American populations, suggesting scenarios such as a serial founder effect.