Thursday, January 4, 2018

Native American DNA History

The genetic history of indigenous peoples of the Americas primarily focuses on Human Y-chromosome DNA haplogroups and Human mitochondrial DNA haplogroups.[1] Autosomal "atDNA" markers are also used, but differ from mtDNA or Y-DNA in that they overlap significantly.[2] The genetic pattern indicates Indigenous Amerindians experienced two very distinctive genetic episodes; first with the initial peopling of the Americas, and secondly with European colonization of the Americas.[3][4] The former is the determinant factor for the number of gene lineages, zygosity mutations and founding haplotypes present in today's Indigenous Amerindian populations.[5]

Analyses of genetics among Amerindian and Siberian populations have been used to argue for early isolation of founding populations on Beringia[6] and for later, more rapid migration from Siberia through Beringia into the New World.[7] The microsatellite diversity and distributions of the Y lineage specific to South America indicates that certain Amerindian populations have been isolated since the initial colonization of the region.[8] The Na-Dené, Inuit and Indigenous Alaskan populations exhibit Haplogroup Q-M242; however, they are distinct from other indigenous Amerindians with various mtDNA and atDNA mutations.[9][10][11] This suggests that the peoples who first settled the northern extremes of North America and Greenland derived from later migrant populations than those who penetrated farther south in the Americas.[12][13] Linguists and biologists have reached a similar conclusion based on analysis of Amerindian language groups and ABO blood group system distributions.[14][15][16]

There is general agreement among anthropologists that the source populations for the migration into the Americas originated from an area somewhere east of the Yenisei River.[17] The common occurrence of the mtDNA Haplogroups A, B, C, and D among eastern Asian and Amerindian populations has long been recognized, along with the presence of Haplogroup X.[18] As a whole, the greatest frequency of the four Amerindian associated haplogroups occurs in the Altai-Baikal region of southern Siberia.[19] Some subclades of C and D closer to the Amerindian subclades occur among Mongolian, Amur, Japanese, Korean, and Ainu populations