The ability to taste the chemical PTC (phenylthiocarbamide) is determined in humans by a dominant allele T, with tasters having the genotypes Tt or TT and nontasters having tt. If 36 percent of the members of a population cannot taste PTC, then according to the Hardy-Weinberg rule, the frequency of the T allele should be
A) 0.36.
B) 0.4.
C) 0.6.
D) 0.64.
E) 0.8

Question

Quizplus · Accepted Answer

According to Hardy-Weinberg equilibrium, the frequency of the recessive genotype (tt) is q^2 = 0.36, so q = 0.6. The frequency of the dominant allele (T) is p = 1 - q = 0.4.

The Ability to Taste the Chemical PTC (Phenylthiocarbamide) Is Determined