Hardy-Weinberg Practice Problems – ANSWER KEY 1. You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following: A. The frequency of the "aa" genotype (q2). q2 = 0.36 or 36% B. The frequency of the "a" allele (q). q = 0.6 or 60 % C.