This tool is a computational device designed to determine if a population’s genetic structure is evolving at a specific locus. It uses observed genotype frequencies to calculate allele frequencies and then predicts expected genotype frequencies under the assumption of no evolutionary influence. Discrepancies between observed and expected values can indicate deviations from the theoretical baseline established by independent allele segregation and random mating. For example, if a user inputs observed frequencies of AA, Aa, and aa genotypes, the computation estimates the ‘p’ and ‘q’ allele frequencies and subsequently predicts the frequencies of each genotype if the population were in a non-evolving state.
The importance of this calculation lies in its ability to provide a null hypothesis against which evolutionary forces can be measured. By quantifying deviations from the predicted equilibrium state, it becomes possible to infer the presence and potentially the magnitude of factors such as natural selection, genetic drift, gene flow, and mutation. The concept originates from the independent work of Godfrey Harold Hardy and Wilhelm Weinberg in 1908, who mathematically demonstrated the conditions under which allele and genotype frequencies remain constant across generations in the absence of evolutionary pressures. This principle serves as a foundational concept in population genetics.
