Suppose a population of flour beetles has 1,000 individuals.Normally the beetles are red; however, this population is polymorphic for a mutant autosomal body color, black, designated by bb.Red is dominant to black, so BB and Bb genotypes are red.Assume the population is at Hardy-Weinberg equilibrium, with equal frequencies of the two alleles.What would be the allele frequencies if a population bottleneck occurred and only four individuals survived: one female red heterozygote and three black males?
A) 0.125 red, 0.875 black
B) 0.875 red, 0.125 black
C) 0.25 red, 0.75 black
D) 0.75 red, 0.25 black
E) 0.5 red, 0.5 black

Question

Quizplus · Accepted Answer

After the bottleneck event, the frequency of the B allele would decrease drastically since there are only three black males left. The frequency of the b allele would be 1 because the surviving female is heterozygous (Bb) and will contribute one B and one b allele to her offspring. Thus, the new allele frequencies would be 0.125 for the B allele (calculated as 1/8) and 0.875 for the b allele (calculated as 7/8).

Suppose a Population of Flour Beetles Has 1,000 Individuals