Practice question

In biallelic system p denotes frequency of one allele, typically dominant or more common A, while q represents other allele a. Because these two exhaust allelic possibilities at locus, their sum equals one. Rearranged gives q = 1 - p, allowing calculation of recessive allele frequency when dominant frequency known through p + q = 1 equilibrium. This complementarity underlies Hardy-Weinberg genotype predictions and estimation of heterozygous carrier frequency as 2pq. If p changes due to selection, q adjusts correspondingly maintaining total allele pool constant.