Passage VI

Tasters are people who can taste Chemical P. Nontasters are people who cannot taste Chemical P. The ability to taste Chemical P is determined by Gene T, which has 2 alleles: T and t. In a population that is not evolving—a population in Hardy-Weinberg equilibrium (HWE)—the frequency of allele T is p and the frequency of allele t is q. Table 1 shows the Gene T genotype(s) of tasters and of nontasters and the expression that predicts the frequency of each genotype in a population in HWE. Table 2 shows p, q, and the frequency of each Gene T genotype for 4 populations in HWE.