Calculate the frequency of the heterozygous genotype in a population using the Hardy-Weinberg principle.

The frequency of heterozygotes (2pq) is calculated by multiplying 2 × p × q, where p is the frequency of the dominant allele and q is the frequency of the recessive allele.

Step-by-Step Solution:
Start with p + q = 1 (where p and q are allele frequencies)
Use Hardy-Weinberg equation: p² + 2pq + q² = 1
Heterozygote frequency = 2pq
Verify: if p = 0.6, q = 0.4, then heterozygote frequency = 2(0.6)(0.4) = 0.48 or 48%

Key Mistake to Avoid:
Don't forget to multiply by 2 when calculating heterozygote frequency (2pq, not just pq).

Quick Tip:
Always cross-check your answer by ensuring all genotype frequencies (p² + 2pq + q²) sum to 1.