Invisible Pink Unicorn writes: "One of the most comprehensive analyses of genetic variation ever undertaken supports the theory that the ancestors of modern native peoples throughout the Americas came from a single source in East Asia across a northwest land bridge some 12,000 years ago. One particular discovery is of a 'unique genetic variant widespread in natives across both continents — suggesting that the first humans in the Americas came in a single migration or multiple waves from a single source, not in waves of migrations from different sources. The variant, which is not part of a gene and has no biological function, has not been found in genetic studies of people anywhere else except eastern Siberia. The researchers say the variant likely occurred shortly prior to migration to the Americas, or immediately afterwards.' The full article is available online from PLoS."