Practice question

For a locus with two alleles A and a at frequencies p and q, p+q=1 accounts for total allele pool. Random mating corresponds biologically to expansion of (p+q) squared in a Punnett square, combining sperm and egg pools independently. This yields genotype frequencies p squared for AA, two pq for heterozygotes formed via two reciprocal combinations, and q squared for aa. Summation across all genotypes equals one, covering entire population. Thus p squared plus two pq plus q squared equals one captures post-mating genotype distribution after one generation and serves as null model for detecting evolutionary forces.