Human albinism is an autosomal recessive trait. Suppose that you find a village in the Andes where 1/4 of the population is albino. If the population size is 1000 and the population is in Hardy-Weinberg equilibrium with respect to this trait, how many individuals are expected to be heterozygotes?

500

Explanation:

According to the given information, the total number of albino people in the population = 1000/4 = 250.

Since albinism is an autosomal recessive trait, the genotype of albino people would be homozygous recessive. Therefore, the frequency of homozygous recessive genotype in the population (q2) = 250/1000 = 0.25.

The frequency of recessive allele (q) = square root of 0.25 = 0.5

Since p+q=1. So, p (frequency of dominant allele) = 1-q = 1-0.5 = 0.5

Frequency of heterozygotes in the population = 2pq = 2 x 0.5 x 0.5 = 0.5 or 50%

Therefore, expected number of heterozygotes in the given population = 50% of 1000 = 500