Arctic genetics comes in from the cold
Despite a well-characterized archaeological record, the genetics of the people who inhabit the Arctic have been unexplored. Raghavan
et al.
sequenced ancient and modern genomes of individuals from the North American Arctic (see the Perspective by Park). Analyses of these genomes indicate that the Arctic was colonized 6000 years ago by a migration separate from the one that gave rise to other Native American populations. Furthermore, the original paleo-inhabitants of the Arctic appear to have been completely replaced approximately 700 years ago.
Science
, this issue
10.1126/science.1255832
; see also p.
1004
The reconstruction of diet and subsistence strategies is integral in understanding early human colonizations and cultural adaptations, especially in the Arctic-one of the last areas of North America to be permanently inhabited. However, evidence for early subsistence practices in Western Alaska varies, particularly with regards to the emergence, importance, and intensity of sea mammal hunting. Here, we present stable carbon and nitrogen isotope data from permafrost-preserved human hair from two new prehistoric sites in Western Alaska, providing a direct measure of diet. The isotope evidence indicates a heavy reliance on sea mammal protein among the earlier Norton-period group (1,750 ± 40 cal BP), confirming that the complex hunting technologies required to intensively exploit these animals were most likely already in place in this region by at least the beginning of 1st millennium AD. In contrast, analysis of the more recent Thule-period hair samples (650 ± 40 cal BP; 570 ± 30 cal BP) reveals a more mixed diet, including terrestrial animal protein. Sequential isotope analysis of two longer human hair locks indicates seasonal differences in diet in a single Norton-period individual but demonstrates little dietary variation in a Thule-period individual. These analyses provide direct evidence for dietary differences among Alaska's early Eskimo groups and confirm the antiquity of specialized sea mammal hunting and procurement technologies. The results of this study have implications for our understanding of human adaptation to maritime and high-latitude environments, and the geographical and temporal complexity in early Arctic subsistence.
Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.
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