The story of how the Chukchi assimilated the Eskimos

Geneticists from Magadan have conducted the first genetics screening of the “Arctic” mutations among the indigenous people of Siberia. In population of the Far North the evolutionary selection has been along the lines of the adjustment to the extreme climatic conditions as well as to the diet consisting of seal and whale meat and fat rich in fatty acids. As a result the so-called Arctic mutations that best fit such a lifestyle became established in the genotype of those people. In terms of biochemistry the most researched is the chromosome 11 mutation of the CPT1A gene.

The story of how the Chukchi assimilated the Eskimos

Scientifically speaking, this gene encodes carnitine palmitoyltransferase 1A, which is one of the key ferments for transferring fatty acids into mitochondrial matrix for their subsequent beta- oxidation. In simple terms, people with such mutation have a low blood cholesterol level despite the fatty food. However, statistically in homozygous carriers of the Arctic version of the CPT1A gene (when the mutation is present in both DNA strands) the Sudden Infant Death Syndrome is detected more frequently, which is related specifically to the deficit of fatty acids. This syndrome is common in American Eskimos and serves as proof of the fact that now that the lifestyle of the Northern people has changed, what used to be a vital mutation now became not only unnecessary, but also dangerous.

Despite the fact that the biochemical aspect of the CPT1A gene mutation and its medical consequences have been thoroughly researched, the population genetics of its carriers (its frequency) among the peoples of the North is virtually non-existent. There have been only partial studies conducted by American and Canadian scientists. Geneticists from the Magadan Institute of Biological Problems of the North have conducted the first large-scale population CPT1A screening among the indigenous population of Siberia (among the Chukchi, Koryaks, Evenks, Evens, Yakuts, Buryats and the Altai people) as well as in Eastern Asia (the Koreans).

High frequency of the Arctic version of the CPT1A gene was discovered only in coastline populations of the North-Eastern Asia: 66% in the Koryaks, 56% in the Chukchi and 30% in the Evens.

The CPT1A gene is usually found in those populations in heterozygous situation, i.e. the related Sudden Infant Death Syndrome is not relevant there. But at the same time the geneticists from Magadan have detected five other DNA loci, the occurrence of which together with the mutation CPT1A gene in various populations of the North helps clarifying the picture of their ethnogenesis.

The picture is very interesting. The “Arctic” mutations linked to the process of hunting ocean wildlife appeared in the ancestors of the Eskimos who lived along Kamchatka’s Eastern coast and along the coast of the sea of Okhotsk. But later more numerous Koryaks and Chukchi moved there. And by the early first millennium the coastline Chukchi and Koryaks drove some Eskimos away from the Asian coast towards the American continent, while assimilating the other part at the same time learning from them the basics of the marine mammal hunting culture as well as useful mutations for such a diet.

In other words, Russian Eskimos that have survived to our days, who are currently less numerous than 2 thousand people, ethnically remain Eskimos, but genetically have to a great extent turned into Koryaks and Chukchi.

(Source — B. A. Malyarchuk, M.V. Derenko, G.A. Denisova, A.N. Litvinov The Proliferation of the Arctic Version of the CPT1A gene in the population of the indigenous people of Siberia. Vavilov Journal of Genetics and Breeding. 2016,No. 20(5), p. 571–575)

Sergey Petukhov

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