Population genetics

Population genetics. The study of the genetic structure and dynamics of the genetic makeup of populations, including changes in the genotype and in the frequency of individual genes, the nature of crossings within a population, interpopulation migrations, and natural and random fluctuations. A study of genes in animal populations provides information on past migrations, evolutionary relationships, the extent of mixing among different species, and methods of adaptation to the environment. It is a relatively recent science, whose pioneering steps in the Union of Soviet Socialist Republics were made in the 1920s and 1930s by S. Chetverikov. The biologist Ivan Shmalhauzen postulated that from the evolutionary standpoint genetic heterogeneity is a peculiar ‘mobilization reserve’ used by populations during gradual or sudden changes in environmental conditions.

[This article originally appeared in the Encyclopedia of Ukraine, vol. 4 (1993).]