Question

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?

Answer 1

The equilibrium frequency of a deleterious allele maintained by mutation-selection balance would be highest in a scenario with a high mutation rate and weak natural selection against the allele. Genetic drift can also contribute to a higher frequency, especially in small populations.

Step-by-step explanation:

When considering mutation-selection balance, the equilibrium frequency of a deleterious allele would be highest in a scenario where the mutation rate introducing the allele is high and natural selection against the allele is relatively weak. In other words, if the deleterious allele is being reintroduced into the population through mutations at a rate that is faster or comparable to the rate at which selection is removing it, the frequency of this allele within the population will be higher. Since deleterious alleles tend to be eliminated by selection, a scenario where selection is not very effective, possibly because the negative effects of the allele are very mild, could also lead to a higher equilibrium frequency. Additionally, in a small population, factors like genetic drift could increase the frequency of the deleterious allele, as random changes in allele frequencies can have a larger impact in smaller populations.