A tool designed to determine if a population is undergoing evolutionary change by comparing observed genotype frequencies to expected genotype frequencies under conditions of genetic equilibrium. It employs the Hardy-Weinberg equation (p + 2pq + q = 1), where ‘p’ represents the frequency of one allele, ‘q’ represents the frequency of the other allele, ‘p’ represents the frequency of the homozygous genotype for ‘p’, ‘q’ represents the frequency of the homozygous genotype for ‘q’, and ‘2pq’ represents the frequency of the heterozygous genotype. Inputting known allele or genotype frequencies into the calculation allows for a determination of whether the population deviates from expected equilibrium proportions.
The utility provides a means to assess the evolutionary forces acting on a population. When observed genotype frequencies deviate significantly from expected frequencies, it suggests that one or more of the assumptions of Hardy-Weinberg equilibrium are being violated: no mutation, random mating, no gene flow, no genetic drift, and no selection. Historically, this principle has been fundamental in population genetics, allowing scientists to quantify and understand the mechanisms driving evolutionary change. Discrepancies between observed and expected values highlight areas for further investigation into factors affecting allele and genotype frequencies.
