Hybrids resulting from matings of inbred strains often show heterosis, explained by two different hypotheses, overdominance and dominance. What are the predictions of these hypotheses?
A) The Overdominance hypothesis relies on dominant/recessive alleles
B) The Dominance hypothesis relies on the fact that in the F1s, the deleterious effects of recessive alleles are masked by dominant ones

Question

Quizplus · Accepted Answer

The Dominance hypothesis suggests that heterosis (hybrid vigor) occurs because the presence of dominant alleles masks the effects of deleterious recessive alleles found in homozygous conditions within inbred populations. This leads to an improvement in the hybrid's performance over its inbred parents. The Overdominance hypothesis, on the other hand, proposes that heterosis results from the superior performance of heterozygous alleles themselves, rather than the masking of recessive alleles by dominant ones. Therefore, the statement about the Dominance hypothesis correctly reflects its prediction regarding the basis of heterosis.

Hybrids Resulting from Matings of Inbred Strains Often Show Heterosis