Hardy-Weinberg law science definition

A fundamental principle in population genetics stating that the genotype frequencies and gene frequencies of a large, randomly mating population remain constant provided immigration, mutation, and selection do not take place. In the simple case of a chromosome locus with two alleles, A and a, with frequencies p and q respectively, the frequency of the homozygotic genotype AA under random mating will be p², of heterozygotic Aa will be 2pq, and of homozygotic aa will be q². The law is named for its formulators, British mathematician Godfrey Harold Hardy (1877-1947) and German physician Wilhelm Weinberg (1862-1937).