Under which scenario will the presence of rare recessive deleterious alleles cause the greatest decline in fitness in a population?
A) when the deleterious allele affects viability but not fecundity
B) when there is a high rate of migration from neighboring populations
C) when the rate of forward and back mutation are nearly equal
D) when mating occurs mostly among close genetic relatives

Question

Quizplus · Accepted Answer

When mating occurs mostly among close genetic relatives, there is a higher likelihood of rare recessive deleterious alleles being expressed in offspring, leading to a decline in fitness. This is because close relatives are more likely to carry the same rare recessive alleles due to shared ancestry. Choice A is incorrect because if the allele only affects viability and not fecundity, then the decline in fitness may not be as severe as it would be if the allele affected both. Choice B is incorrect because high rates of migration can introduce genetic diversity and potentially dilute the negative effects of rare deleterious alleles. Choice C is incorrect because the rate of forward and back mutation may not necessarily have a significant impact on the decline in fitness caused by rare recessive deleterious alleles.

Under Which Scenario Will the Presence of Rare Recessive Deleterious