What is the Hardy-Weinberg equation and what is it used for?

The Hardy-Weinberg equation is a model predicting allele frequency in an population, under the assumption that the frequency of alleles in a population does not change and will contribute equally to the next generation (No natural selection, no mutation, no migration of individuals, random mating). No real life population satisfies all the criteria, but it is useful for predicting allele frequencies in an ideal population. Equation = p² + 2pq + q² = 1 Where p² is the frequency of homozygous dominant (AA), 2pq is the frequency of heterozygous genotypes (Aa), and q² is the frequency of homozygous recessive (aa), where p + q = 1 (100% of the population has either the dominant or recessive allele). In A-level exams the equation is often used to predict the allele frequency of a specific genotype (eg . carrier for a disease) when one of the genotype/phenotype/allele frequencies is provided.