The branch of genetics that studies the ways in which the frequencies of different alleles in populations of organisms change as a result of natural selection, mutation, genetic drift and gene flow as well as other process and their mechanisms (e.g., assortative mating). It became a cornerstone of the Modern synthesis due to work of Ronald S. Fisher (1890-1962), John B. S. Haldane (1892-1964) and Sewall Wright (1889-1988), who together also laid the foundations for the related theory of quantitative genetics.
See Allele, Evolutionary biology, Inclusive fitness, Mendelian genetics, Modern synthesis, Polymorphism, Population (biology and ecology), Popularion (statistics), Quantitative genetic theory, Theory of natural selection