Genetic demography of populations of three megalopolises in relation to the problem of creating genetic databases

Based on data collected from urban residents by questionnaire, the basic parameters of the genetic-demographic structure of populations of the three megalopolises, i.e., Moscow, Kharkov, and Minsk, have been calculated, including the migration coefficients and their dynamics in generations, the radius of the cities migration attraction, the parameters of marriage structure (the proportion of interethnic marriages, the level of intraethnic assortative mating the marital distances), and the gene flow between the ethnic groups. Representatives of the most numerous ethnic group of each megalopolis show significant amount of admixture. For Russians of Moscow, Ukrainians of Kharkov, and Belarusians of Minsk, the proportion of individuals whose ancestors were all born in the given city for at least three generations and belonged to the same nationality turned out to be very low (4.75% in Moscow, 1.83% in Kharkov, and 3.13% in Minsk). This finding questions the formation of a reference population in the megalopolis as a sampling of aboriginals of certain ethnic origins. In the paper, we justify principles of creating genetic databases for the population of the megalopolis taking into account the complexity and dynamism of its population structure.