mtDNA variation among Greenland Eskimos: The edge of the Beringian expansion

The Eskimo-Aleut language phylum is distributed from coastal Siberia across Alaska and Canada to Greenland and is well distinguished from the neighbor ing Na Dene languages. Genetically, however, the distinction between Na Den e and Eskimo-Aleut speakers is less clear. In order to improve the genetic characterization of Eskimos in general and Greenlanders in particular, we h ave sequenced hypervariable segment I (HVS-I) of the mitochondrial DNA (mtD NA) control region and typed relevant RFLP sites in the mtDNA of 82 Eskimos from Greenland. A comparison of our data with published sequences demonstr ates major mtDNA types shared between Na Dene and Eskimo, indicating a comm on Beringian history within the Holocene. We further confirm the presence o f an Eskimo-specific mtDNA subgroup characterized by nucleotide position 16 265G within mtDNA group A2. This subgroup is found in all Eskimo groups ana lyzed so far and is estimated to have originated <3,000 years ago. A founde r analysis of all Eskimo and Chukchi A2 types indicates that the Siberian a nd Greenland ancestral mtDNA pools separated around the time when the Neo-E skimo culture emerged. The Greenland mtDNA types are a subset of the Alaska n mtDNA variation they lack the groups D2 and D3 found in Siberia and Alask a and are exclusively A2 but at the same time lack the A2 root type. The da ta are in agreement with the view that the present Greenland Eskimos essent ially descend from Alaskan Neo-Eskimos. European mtDNA types are absent in our Eskimo sample.