"DNA from the 8,500-year-old skeleton of an adult man found in 1996, in Washington, is more closely related to Native American populations than to any other population in the world, according to an international collaborative study conducted by scientists at the University of Copenhagen and the Stanford University School of Medicine." Source: Stanford Medicine News Center.
Note: This still hasn't resolved the controversy surrounding Kennewick Man. According to NBC News, "[s]ome of the scientists who have studied the 8,500-year-old skeleton known as Kennewick Man, also known as the Ancient One, say they could learn more from further studies — and they'd be reluctant to see the remains handed over to the Native American tribes that claim him."
Comment: Some archaeological discoveries are so tied up with identity politics that it's hard to trust anything that's said about them, even when it comes from apparently unimpeachable sources. Assuming that this DNA study is accurate, however, I'm still not sure what it means to say that Kinnewick Man is "more closely related to Native American populations than any other population in the world." (Emphasis added)
The term "Native American" is a misnomer since the first paleo-indians to arrive in North America came here from Asia. Technically speaking, Native Americans are only "native" to the continent in the sense that they may have been the first arrivals (an issue which is still up in the air). And who were these prehistoric Asians / paleo-indians in the first place?
Europeans migrated into Asia. Their ancestors probably originated somewhere in central Asia. During their migrations, Europeans mixed with Asian populations and some of their ancestors may have crossed the Bering Land Bridge into North America. Another DNA study shows that native americans have European roots, so the reality of Kinnewick Man is a lot more complicated than it seems.