A single population of prehistoric Siberians crossed the Bering Strait into Alaska and subsequently fanned out to populate North and South America, according to a new genetic analysis of present-day indigenous Americans.
The study also hints that early Americans reached Central and South America by migrating down the Pacific coast by land or sea and only later spread into the interior of South America.
"We have good evidence that a single migration [from Siberia] contributed a large fraction of the ancestry of the Americas," says population geneticist Noah Rosenberg of the University of Michigan in Ann Arbor, who led the large international study team.
The finding draws on the largest database of Native American genetics ever compiled. The data include DNA from nearly 500 people belonging to 29 groups scattered across Canada, Mexico, Central America, and South America. The researchers also studied samples from 14 Tundra Nentsi individuals living in eastern Siberia