A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?
A) 0.7
B) 0.49
C) 0.21
D) 0.42
E) 0.09

Question

Quizplus · Accepted Answer

In Hardy-Weinberg equilibrium, the frequency of alleles in a population stays constant from generation to generation. According to the question, the frequency of A1 allele in the population is 0.7. Therefore, the frequency of A2 allele must be 0.3 (since there are only two alleles in the population). Using the formula (p + q)^2 = 1, where p is the frequency of A1 allele and q is the frequency of A2 allele, we can calculate the proportion of flies that carry both A1 and A2 alleles: (0.7 + 0.3)^2 = 0.42. Therefore, the correct answer is D.

A Fruit Fly Population Has a Gene with Two Alleles