In a population of butterflies, the allele frequency of A is 0.7 and the allele frequency of a is 0.3. According to Hardy-Weinberg equilibrium, what is the expected frequency of the heterozygous genotype (Aa) in this population?

• A. 0.09
• B. 0.49
• C. 0.21
• D. 0.42

Answer: (D)

Verified step by step guidance

1. Identify the allele frequencies given: frequency of allele A is \(p = 0.7\) and frequency of allele a is \(q = 0.3\).
2. Recall that under Hardy-Weinberg equilibrium, the genotype frequencies can be calculated using the formula: \(p^2\) for homozygous dominant (AA), \$2pq\( for heterozygous (Aa), and \)q^2$ for homozygous recessive (aa).
3. Since the problem asks for the frequency of the heterozygous genotype (Aa), use the formula for heterozygotes: \$2pq$.
4. Substitute the allele frequencies into the formula: \$2 \times 0.7 \times 0.3$.
5. Calculate the product to find the expected frequency of the heterozygous genotype in the population.