Consider a population of 20 AA, 40 Aa, and 40 aa individuals. A is a dominant allele causing death before reproductive age. What are the genotypic frequencies of the next generation after selection?

Question

Quizplus · Accepted Answer

The A allele causes death before reproductive age, meaning that all AA individuals will not contribute to the next generation. Therefore, the genotypic frequencies of the next generation will only be Aa and aa. The frequency of aa individuals will increase since they are the only ones able to reproduce. We can use the Hardy-Weinberg equation to calculate the expected genotype frequencies after selection:

p^2 + 2pq + q^2 = 1

Let q^2 = frequency of aa individuals
Therefore, q^2 = 40/100 = 0.4

p + q = 1
Therefore, p = 1 - q = 0.6

Let 2pq = frequency of Aa individuals
Therefore, 2pq = 2(0.6)(0.4) = 0.48

Thus, the expected genotypic frequencies of the next generation are:
AA = 0%
Aa = 48%
aa = 52%

Therefore, the best choice is B, all aa individuals.

Consider a Population of 20 AA, 40 Aa, and 40