Polymorphism of mitochondrial DNA region V in native and migrant inhabitants of Northeast Asia

: Data on polymorphism of the V region of mitochondrial DNA (mtDNA) in eastern Slavs from Magadan (N = 108), Asian Eskimos (N = 21), and coastal Chukchi (N = 10) are presented. The region V insertion-deletion polymorphism was shown to be absent in the samples of native and immigrant population of northeastern Asia. The Hae III-Ava II restriction polymorphism of the 8249-8254 bp part of this mtDNA region was found only in eastern Slavs. In them, the variant Hae III(-)/Ava II(+) and the novel type of polymorphism Hae III(-)/Ava II(-) were recorded at frequencies 2.8% and 1.85%, respectively. The low level of diversity of mtDNA types in Arctic populations of the world is discussed. A hypothesis is advanced that the low level of mtDNA diversity in Arctic population of humans is determined by several factors. These include an initially low number of mtDNA types in forming ancestral populations, genetic drift, isolation, and continuous adaptation of the populations. The latter is associated with selection of genotypes optimal for living in the extreme climatic and geographic conditions of the North; some of these genotypes control a low level of free oxygen radicals in the cell.