AP BIOLOGY

Detailed explanation-1: -The “2pq” in equation shows frequency of heterozygotes in the population. In the question, the genotype frequency of recessive population is (q2) = (16% or 0.16). Hence, frequency of recessive allele = q = 0.16 = 0.4.

Detailed explanation-2: -In a certain population which is in Hardy-Weinberg equilibrium, there are only two eye colours: brown (dominant) and blue (recessive). 16 % have blue eyes in the population.

Detailed explanation-3: -If the homozygous recessive genotype makes of 16% of the population the fraction of the recessive allele is the square root of the q (recessive allele fraction )= √¯ 0.16 = 0.4. The dominant allele is 1-p = 1-0.4 = 0.6.

Detailed explanation-4: -To determine q, which is the frequency of the recessive allele in the population, simply take the square root of q2 which works out to be 0.632 (i.e. 0.632 x 0.632 = 0.4). So, q = 0.63. Since p + q = 1, then p must be 1-0.63 = 0.37.