Panmixia

Panmixia, also known as random mating, is a biological concept describing a population where all individuals are equally likely to mate with any other individual, regardless of genotype or phenotype. It is a fundamental assumption in many population genetics models, including the Hardy-Weinberg principle. Under panmixia, the frequencies of alleles within a population will remain constant from one generation to the next, provided that other evolutionary influences, such as mutation, selection, gene flow, and genetic drift, are negligible.

In a panmictic population, mating is considered to be entirely random with respect to the genes being studied. This does not necessarily imply that mating is random with respect to all traits. For example, individuals might choose mates based on size or age, but as long as these traits are not genetically correlated with the genes under consideration, the assumption of panmixia remains valid for those specific genes.

Departures from panmixia, such as assortative mating (where individuals with similar phenotypes mate more frequently) or disassortative mating (where individuals with dissimilar phenotypes mate more frequently), can alter allele and genotype frequencies within a population and can have significant evolutionary consequences. Inbreeding, a form of assortative mating where individuals mate with relatives, is a common departure from panmixia.