Hemophilia type A is an Xlinked recessive trait If in a cert

Hemophilia type A is an X-linked recessive trait. If in a certain population, 1 in 5000 males has type A hemophilia, what is the frequency of carriers (heterozygotes) among females? You can assume HW equilibrium applies. In the mountain people of Yahoo-la, the recessive allele b (for bigfoot) causes abnormally large feet and excessive hairiness. Unfortunately, one winter, all of the bigfoot individuals were killed after being mistaken for abominable snowmen by panicked villagers from the lowlands. Assuming the frequency of the b allele was 1/2 initially, and that mating is random with respect to foot size, answer the following questions. (Calculations for this problem can be done easily using fractions try to give your calculator a rest) What were the initial frequencies of the three genotypes? What were the frequencies of the three genotypes in the survivors after the fateful winter? What are the predicted genotype frequencies in the offspring of the survivors, assuming they mate randomly?

Solution

Hemophilia is X-linked recessive trait. 1 in 5000 mlaes have type A hemophilia. frequency of recessive phenotype = q2 =1/5000 frequency of recessive allele = q =1/70.71 = 0.014 then p = 1-q = 1-0.014 = 0.986 now p2 + 2pq + q2 = 1 (0.986)2 + 2 (0.986)(0.014) + (0.014)2 = 1 0.972 +0.02760 +0.000196 =1 Thus the heterozygotes = 0.0276 or 2.76 %