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) 0.42
D) 0.21

Question

Quizplus · Accepted Answer

The Hardy-Weinberg principle can be used to calculate the frequencies of genotypes in a population if the allele frequencies are known and the population is in equilibrium. The frequency of allele A1 is given as 0.7 (or 70%), so the frequency of allele A2 is 1 - 0.7 = 0.3. The proportion of heterozygotes (A1A2) can be calculated using the formula 2pq, where p is the frequency of one allele (A1 = 0.7) and q is the frequency of the other allele (A2 = 0.3). Thus, 2pq = 2 * 0.7 * 0.3 = 0.42.

A Fruit Fly Population Has a Gene with Two Alleles