Use the following to answer questions:
Suppose you have a population of flour beetles with 1,000 individuals. Normally the beetles are red; however, this population is polymorphic for a mutant autosomal body color, black, designated by b/b. Red is dominant to black, so B/B and B/b genotypes are red. Assume the population is in Hardy-Weinberg equilibrium, with equal frequencies of the two alleles.
-What would be the expected frequencies of the red and black phenotypes?
A) 0.5 red; 0.5 black
B) 0.75 red; 0.25 black
C) 0.25 red; 0.75 black
D) 0
E) Insufficient information is given to answer the question.

Question

Quizplus · Accepted Answer

In a population in Hardy-Weinberg equilibrium with two alleles, the frequency of homozygous dominant individuals (B/B) is represented by p², the frequency of homozygous recessive individuals (b/b) is represented by q², and the frequency of heterozygous individuals (B/b) is represented by 2pq. Since we know that the frequencies of the two alleles are equal, we can set p = 0.5 and q = 0.5. Therefore, the expected frequency of homozygous dominant individuals (red, B/B) is 0.25 (0.5 x 0.5), the expected frequency of heterozygous individuals (red, B/b) is 0.50 (2 x 0.5 x 0.5), and the expected frequency of homozygous recessive individuals (black, b/b) is 0.25 (0.5 x 0.5). Thus, the expected frequencies of the red and black phenotypes are 0.75 and 0.25, respectively, which corresponds to choice B.

Use the Following to Answer Questions