Genetic demography of the Moscow population: migration, outbreeding and assortative mating.

Using marriage records, census data, and other statistical sources, some demographic parameters of Moscow population in 1955 and 1980 have been studied, such as age at marriage, birthplace, nationality and profession of permanent residents. Migration has been shown to be the main factor of Moscow population dynamics. Genetically significant, quantitative and geographic parameters of this process have been obtained (migration rates, migration and marital distances, proportion of interethnic marriages). During the past two centuries the mean distance travelled by migrants, arriving in Moscow, increased by several times, the genetic contribution from eastern and southern parts of the country being especially marked. In the period of maximum migration rates the percentage share of marriages between Moscow-born people was only 10%. The percentage share of interethnic marriages was 14.75% in 1955 and 16.53% in 1980. The degree of isolation by distance, predicted by Malécot's model, appeared to be quite low. Positive assortative mating for nationality, birthplace, age and profession was characterized as a factor, counteracting outbreeding. While the deleterious effects of isolation and inbreeding are well known, the genetic consequences of alternative state are still obscure.