Question

Moths have eyespots on their hindwings or not. Eyespots are produced by dominant alleles. Moths with eyespots average 100 eggs per female while moths without eyespots average 85 eggs per female.

a) If the frequency of eyespot alleles in a new population is 0.025, then how many generations pass until the eyespot allele is fixed?

b) What mutation rate would produce a population with a recessive allele frequency of 0.005? How does that mutation rate compare to the average observed rate of DNA copying errors (after repair enzymes do their work)?

Answer 1

(a) If the frequency of eyespot alleles in a new population is 0.025 then it would take 4-5 generations pass until the eyespot allele is fixed

(b) If a population has a completely recessive allele, but a mutation occurs once in every 100 gametes, then in one generation the mutation rate is 0.01 x 1.0 = 0.01, meaning after one generation, 0.99 of the alleles will be with eyespots and 0.01 will be without eyespots. Then for a recessive allele frequency of 0.005 the mutation rate would be 0.01/0.05 = 0.2

(c) The observed rate of DNA copying errors or the breeding rate would be 0.25 with mutation rate of 0.02.