Isonymy as an indicator of inbreeding in child populations of Yamal and Gyda tundra

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It is known that the term «inbreeding» refers to a descendant of close relatives. As a result of inbreeding in the population the number of homozygotes increases and thus the number of heterozygotes reduces, which degrades the quality of the population (inbreeding-depression), since it increases the frequency of diseases associated with recessive genes in such children. In isolated populations individuals with adverse signs as a result of inbreeding eventually get culled of (Kirkpatrick et al., 2000). Decrease in genetic di-versity as a result of inbreeding, usually leads to that the individual and the population lose their ability to adapt to changing environmental conditions, as many body functions are genetically determined. Simple statistical calculations indicate that all human beings are relatives to some extend. The inbreeding coefficient can be determined by analyzing the family tree based on the number of ancestors to the shared ancestor for both parents. The purpose of this study was to determine the inbreeding coefficient by means of isonymic analysis of the population of 2043 Nenets and Khanty children living in the villages of the Yamal region as well as in tundra assigned to boarding schools located in villages Salemal, Panaevsk, Yar-Sale, Novy Port and Gyda of the Yamal-Nenets autonomous destrict. Inbreeding coefficient was calculated using marital isonymy to estimate the frequency of consanguineous marriages as a measure of inbreeding (Crow and Mange,1965). We calculated the frequency of prospective isonymic marriages for individual Nenets and Khanty surnames for inhabitants of Yar-Sale, Salemal, Panaevsk, Novy Port and Gyda tundra. In Gyda tun-dra for one of the not very common in the region surnames the highest frequency of prospective consanguineous marriages was revealed (0.189). Values of the coefficient of random inbreeding for inhabitants of Yamal and Gyda tundra vary from 0.02 to 0.058 which is much higher than for example in the population of one of the Yakutia regions (0.0007) (Kucher et al., 2010) or in the population of Kirovsk region (0.00321-0.01063) (Kadyshev, 2011). In the population of Gyda tundra we revealed the highest coefficient of random inbreeding (0.058), which is the third world‘s largest value pub-lished to date.