In a large population a recessive genetic disorder occurs in 1 in 2500 individuals. The disease allele also confers a heterozygote advantage: heterozygotes have a fitness 10 % higher than normal homozygotes, while homozygous recessives have a fitness 50 % lower than normal homozygotes. Assuming Hardy-Weinberg equilibrium and random mating:

(a) Calculate the allele frequency ($q$) of the disease allele.
(b) Determine the expected proportion of heterozygotes in the next generation after selection (as a percentage, to one decimal place).

Question

In a large population a recessive genetic disorder occurs in 1 in 2500 individuals. The disease allele also confers a heterozygote advantage: heterozygotes have a fitness 10 % higher than normal homozygotes, while homozygous recessives have a fitness 50 % lower than normal homozygotes. Assuming Hardy-Weinberg equilibrium and random mating:

(a) Calculate the allele frequency ($q$) of the disease allele.
(b) Determine the expected proportion of heterozygotes in the next generation after selection (as a percentage, to one decimal place).

Accepted Answer

q = 0.02; heterozygote proportion ≈ 4.3%

Gce Model Questions Vol1 2021 Biology Question 5

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