Analysis of the level of population endogamia as the basis of population-genetic and medical-genetic studies

Background: When conducting population-genetic and genetic-epidemiological studies, the endogamy index should be taken into account to assess the level of the elementary population, characteristics of the migration activity of the population and the degree of isolation of the population. The aim of the study: To assess the level of endogamy among the entire population of the Belgorod region in the modern period of time. Materials and methods: Based on 11052 marriage records of the Registry Office in the Belgorod region for 2016-2018, the endogamy index was studied among the entire population in all administrative units of the Belgorod region – 21 districts. The endogamy index was calculated on the basis of data on the place of birth of spouses, as the proportion of husbands and wives born in a given population. Results: It was found that in the district populations of the Belgorod region, the endogamy index at the district level varied from 0.33 to 0.68 with an average value for the region of 0.46, which is within the range of variability of this indicator among the Russian populations of the Russian Federation. At present, the endogamy of regional populations, which include big and large cities, exceeds this indicator among the rural population. For highly urbanized districts of the region, the size of the elementary population corresponds to the administrative boundaries of the district, while for the rural population, the size of the elementary population exceeds the boundaries of the district. It should be noted that the reduced values of this indicator for the rural population correspond to general migration trends. An increase in the inflow of migrants to the regional populations of the Belgorod region leads to a decrease in the endogamy index, as evidenced by the established inverse correlations between the number of migrants per 1000 inhabitants over three time periods (1990, 2000, and 2019) and the endogamy index. Conclusion: The populations of the Belgorod region are characterized by high migration activity, which leads to a decrease in the level of endogamy among the population. At present, the size of the elementary population in the Belgorod region corresponds to the area or slightly exceeds it.