Suppose 64% of a remote mountain village can taste phenylthiocarbamide (PTC) and must, therefore, have at least one copy of the dominant PTC taster allele. If this population conforms to Hardy-Weinberg (1908) equilibrium for this gene, what percentage of the population must be heterozygous for this trait?
A) 16%
B) 32%
C) 40%
D) 48%

Question

Quizplus · Accepted Answer

To find the percentage of heterozygous individuals, use the Hardy-Weinberg principle: p^2 + 2pq + q^2 = 1. Here, p^2 represents homozygous dominant, 2pq represents heterozygous, and q^2 represents homozygous recessive. Given that 64% can taste PTC, p^2 + 2pq = 0.64. Since q^2 = 0.36 (36% cannot taste PTC), q = 0.6. Therefore, p = 0.4. The heterozygous frequency is 2pq = 2(0.4)(0.6) = 0.48 or 48%.

Suppose 64% of a Remote Mountain Village Can Taste Phenylthiocarbamide