Genotypic Frequency of Heterozygote in Hardy-Weinberg Equilibrium

Question

If gene frequency of A = 0.7 and a = 0.3, what is the genotypic frequency of the heterozygote (Aa)?

Select an answer

If gene frequency of A = 0.7 and a = 0.3, what is the genotypic frequency of the heterozygote (Aa)?

  1. 0.42 — Correct Answer
  2. 0.21
  3. 0.49
  4. 0.09
Explanation:
Correct Answer: 0.42

Using the Hardy-Weinberg equation, the genotypic frequency of the heterozygote (Aa) = 2pq.

Calculation
  • p = 0.7 (frequency of A)
  • q = 0.3 (frequency of a)
  • Frequency of Aa = 2pq = 2 × 0.7 × 0.3 = 0.42
Complete Genotypic Frequencies
Genotype Frequency Value
AA p² = (0.7)² 0.49
Aa 2pq = 2×0.7×0.3 0.42
aa q² = (0.3)² 0.09
Total p² + 2pq + q² = 1 1.00

Maximum heterozygote frequency (0.50) occurs when p = q = 0.5.

📚 About this Topic — Animal Genetics & Breeding

This multiple choice question is from Animal Genetics & Breeding, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Genetics & Breeding to strengthen your preparation.

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