Question

Use the equation for Hardy-Weinberg equilibrium for the following questions. p + q = 1 p2 + 2pq + q2 = 1

In domestic cats, the allele for short hair (L) is dominant and the allele for long hair (l) is recessive. You are studying a population of cats found on Iwato Island and have determined that the frequency of the recessive long hair allele is q = 0.3.

A) What is the frequency of the dominant allele for short hair? p =

B) What is the percentage of cats who have heterozygous genotypes?

C) What percentage of cats on this island will have long hair phenotypes?

D) Describe one condition that could change the allele frequencies (the values of p and q) in a population.

Answer 1

A) The allelic frequency of recessive allele q = 0.3

Therefore, the alleleic frequency of dominant allele p = 1 - 0.3 = 0.7

B) The heterozygous genotype = 2pq

The frequency of heterozygous cats = 2 x 0.3 x 0.7 = 0.42

So, percentage of the allelic frequency is = 42 %

C) Percentage of long hair phenotypes = recessive allele = q = 0.3

Therefore, percentage of long hair phenotypes = 3%

D) Allelic frequencies in Hardy-Weinberg equilibrium can be changed when one of the assumptions is not followed. A condition that can change the allelic frequencies is - genetic drift. The genetic drift is a phenomenon when a part of a population drifts to a different habitat far from the original population thereby causing a shift in the genes that can then evolve separately in the new environment.