Random mating populations: Hardy–Weinberg Principle

Abstract

AbstractWe introduce the Hardy–Weinberg principle, which is the fundamental model of population genetics. The use of mathematical models is essential to understand the effects of Mendelian inheritance and the evolution of allele frequencies in natural populations. The Hardy–Weinberg model assumes random mating, infinite population size, no natural selection, no mutation, and no immigration. There are two primary outcomes of the Hardy–Weinberg model: (1) Hardy–Weinberg equilibrium and (2) Hardy–Weinberg proportions. Testing for Hardy–Weinberg proportions in population samples is usually the first step in describing genotypic variation in natural populations. We consider several explanations for why genotypic proportions might not be in Hardy–Weinberg proportions. The Hardy–Weinberg model is useful for estimating allele frequencies in natural populations. We describe two measures for comparing the amount of genetic variation in natural populations: heterozygosity and allelic richness.