Native Americans are descended from a single group that migrated from Siberia 12,000 years ago, new genetic research suggests. An alternate theory suggested that Native American ancestors migrated in several waves over land and sea from Asia, but the new study shows that native peoples from all over the Americas share a single gene mutation also seen in Siberian natives, AFP reports.
"If there were a large number of migrations, and most of the source groups didn't have the variant, then we would not see the widespread presence of the mutation in the Americas," says a geneticist. The original pioneers trekked over a land bridge across the Bering Strait, and genetic diversity increased as the population spread south. (Read more Native American stories.)