Question

In humans, albinism is caused by loss-of-function mutations in genes involved in the synthesis of melanin, the dark pigment in skin. only people homozygous for a loss-of-function allele (genotype aa) have the albino phenotype. in americans of northern european ancestry, albino individuals are present at a frequency of about 1 in 10,000 (or 0.0001). assuming that genotypes are in hardy−weinberg equilibrium, what is the predicted frequency of caucasians in the united states who carry a single allele for albinism?

Answer 1

If the albino individuals are present at a frequency of about 1 in 10,000 (or 0.0001); then;

aa = 0.0001

a = 0.01

Using Hardy-Weinberg principle of p + q = 1

p + 0.01 = 1

p = 1 – 0.01 = 0.99

Using Hardy-Weinberg equation; p2 + 2pq + q2 = 1

Carriers of albino allele are the heterozygous population (2pq);

2*.099*0.01 = 0.0198

The frequency is 0.0198