Assuming that a deleterious allele is maintained in a population by mutation-selection balance, which scenario below describes the case where you would expect the equilibrium frequency of the allele to be highest?
A) The mutation rate is low; the allele is highly deleterious.
B) The mutation rate is low; the allele is slightly deleterious.
C) The mutation rate is high; the allele is highly deleterious.
D) The mutation rate is high; the allele is slightly deleterious.

Question

Quizplus · Accepted Answer

In a mutation-selection balance, the equilibrium frequency of a deleterious allele is determined by the rate at which new mutations introduce the allele into the population and the rate at which selection removes it. A high mutation rate increases the frequency of the allele, and if the allele is only slightly deleterious, selection against it is weaker, allowing it to reach a higher equilibrium frequency.

Assuming That a Deleterious Allele Is Maintained in a Population