Hardy–Weinberg equilibrium, selection and genetic drift

BiologyGeneticsAges 17–18

A randomly mating population with two alleles A and a: genotype frequencies p², 2pq and q² are calculated and plotted every generation alongside an illustrative cloud of individuals. With no selection and a large population, allele frequencies stay constant across generations (Hardy–Weinberg equilibrium); turn on selection against the recessive phenotype or shrink the population size to see allele frequency shift directionally or fluctuate at random, sometimes eliminating an allele altogether.