Hardy-Weinberg Principle

The Hardy-Weinberg principle is a foundational model in population genetics stating that allele and genotype frequencies in a population will remain constant across generations in the absence of evolutionary influences such as mutation, migration, genetic drift, natural selection or non-random mating. The principle was formulated independently in 1908 by English mathematician Godfrey Harold Hardy and German physician Wilhelm Weinberg, expressing the equilibrium genotype frequencies for a gene with two alleles algebraically. Because real populations almost always violate one or more of the principle's assumptions, it functions chiefly as a null hypothesis, or baseline, against which geneticists measure whether and how much evolution is actually occurring in a given population.