The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Understanding the colonization of the North American Arctic: The results of whole mitochondrial genome sequencing of Iñupiat populations of the Alaskan North Slope


1Division of Endocrinology, Metabolism, and Molecular Medicine, Feinberg School of Medicine, Northwestern University, 2Department of Anthropology, Northwestern University

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Conventional understanding of North American Arctic prehistory identifies two successive colonization events in which populations rapidly moved eastward from the Alaskan North Slope to Greenland (at 4000 YBP and 800 YBP). The latter Neo-Eskimo migration (known as the Thule expansion) resulted in a complete replacement of the previous Paleo-Eskimo inhabitants, and formed the ancestral gene pool of all modern Iñupiat/Inuit peoples.

To build on our understanding from previous studies of mtDNA hypervariable sequences, we sequenced 139 complete mitochondrial genomes from Iñupiat populations of the Alaskan North Slope, the hypothesized geographic origin of the Thule culture. As expected, we found North American Arctic-specific haplogroups A2a, and A2b. We additionally found a previously undescribed A2 haplotype that does not match any published non-Arctic A2. We found several individuals belonging to haplogroup D4b1a2a1a1 (previously known as D3), with a possible back mutation at 16093. D2 was also found in the North Slope sample, but appears to be distinct from the Paleo-Eskimo Saqqaq D2, and in the hypervariable region more closely resembles Aleutian D2 haplotypes. Finally, we discovered two occurrences of the recently recognized pan-American founder haplogroup C4c1, which has been hypothesized to be a post LGM expansion from Beringia. We apply coalescence methods to date these haplogroups, and discuss the implications of this unexpected genetic diversity for both the colonization of the Arctic and the earlier peopling of the Americas further south.

IPY: Reconstruction of Human Genetic History Along the North Slope (OPP-0732846 and OPP-0732857)

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