A population in Hardy-Weinberg equilibrium has the possible genotypes AA, Aa and aa. If the frequency of the A allele is 50 per cent in one generation, then the frequency of aa homozygotes in the next generation will be
A) 0.25.
B) 0.33
C) 0.5.
D) 0.75.
E) 1.

Question

Quizplus · Accepted Answer

In Hardy-Weinberg equilibrium, the frequency of alleles in the population remains constant from one generation to the next. If the frequency of the A allele is 50% (or 0.5), then the frequency of the a allele is also 50% (or 0.5). The frequency of aa homozygotes can be calculated using the equation p^2 + 2pq + q^2 = 1, where p is the frequency of one allele (A), q is the frequency of the other allele (a), p^2 is the frequency of AA, 2pq is the frequency of Aa, and q^2 is the frequency of aa. Therefore, the frequency of aa homozygotes is q^2 = 0.5^2 = 0.25.

A Population in Hardy-Weinberg Equilibrium Has the Possible Genotypes AA