Friday, November 22, 2013

No News about the Origin of the First Americans

Lots of news stories lately about the the genome of a Siberian boy who died about 24,000 years ago, published under headlines about the origin of Native Americans. The basic story is that the boy is closely related to American Indians, especially in the male line, but more related to people of western than eastern Asia. His Y chromosome type is MA-1, which is "basal", or close to the origin, for most men of western Eurasia. His mitochondrial DNA, inherited through the female line, is group U, which was once widespread across Eurasia but is not known among American Indians.

This is very interesting, but it is not news. Most American Indians belong to one of two closely related Y chromosome lineages, and it has been known for several years that these are connected to western rather than eastern Eurasia. Their mitochondrial DNA, inherited through women, is more diverse, since there are at least five separate lineages. A friend of mine suggested to me more than two years ago that American Indian DNA tells the story of one band of men from western Asia or eastern  Europe who traveled across the continent picking up women at five different places along the way before they crossed the Bering Strait. DNA probably can't really be interpreted in that way, but that is the naive reading of the evidence and has been for years.

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