Molecular Genetic Evidence from Contemporary Populations for the Origins of Native North Americans

An overview of the current molecular genetic evidence for the origins of North American populations is presented, including specific examples from the authors’ work with the Aleutian Island inhabitants. Shared mitochondrial DNA and Y-chromosome DNA markers among Siberians and Native Americans point to a Pleistocene migration from Siberia into the Americas via Beringia. There was likely a later migration from Siberia to Alaska, based on the analysis of whole-genome sequence data from a Greenland Paleoeskimo that clusters this individual with Siberian populations. Coalescence date estimates for Native American mitochondrial DNA and Y-chromosome DNA haplogroups indicate that there was a population expansion approximately 15,000–18,000 that was associated with a pre-Clovis settlement of the Americas and coastal migration, and then a later expansion of circum-Arctic populations. Settlement of the Aleutian Archipelago took place via east-to-west migration of Aleut kin groups, accompanied by a clinal loss in mitochondrial DNA haplotype diversity.