Question

A tiger color variant with a white coat and black stripes occurs due to an autosomoal recessive mutation in a transport protein. Homozygous dominant individuals (genotype DD) have wild-type orange coloration. Heterozygotes (Dd) also have the wild-type coloration but are carriers for the white allele. Homozygous recessive individuals (dd) have the white phenotype

A population of tigers has a recessive allele frequency of 0.2.

What proportion of the tigers are expected to be heterozygous carriers if the population is in hardy-weinberg equilibrium

Answer 1

A population of tigers has a recessive allele frequency of 0.2. Hence dd is 0.2.

Hence q​​​​​​2​​​​​ = 0.2 , q = 0.45

There P + q = 1, hence p = 1-q = 0.55

Thr proportion of the tigers that are expected to be heterozygous carriers i.e Dd if the population is in hardy-weinberg equilibrium is 2pq

P​​​​​​2 + 2pq + q​​​​​​2 = 1 (hardy-weinberg equilibrium)

0.3 + 2pq + 0.2 = 1

2pq = 1 - 0.2 - 0.3 = 0.5

Answer - The proportion of the tigers are expected to be heterozygous carriers is 0.5.