Hardy-Weinberg Equilibrium

A state in which allele and single locus genotype frequencies do not change (on average) from one generation to the next in a population. When alleles in a population are independent, allele and genotype frequencies are related through the Hardy-Weinberg principle: for a locus with 2 alleles P and Q at frequencies of p and q, homozygotes for P are found at frequency p2, homozygotes for Q are found at a frequency of q2, and heterozygotes are found at a frequency of 2pq. Use of the theta correction removes the need to assume Hardy-Weinberg equilibrium in the population for which a frequency database is constructed.