Question

The Dobzhansky-Muller model explains hybrid infertility in crosses between two close species (such as the fruit flies D. simulans and D. melanogaster). Which of the following is the best explanation of this model?

a. Hybridization between the two sister species is impossible because of the imminent hybrid sterility.

b. Epistatic interactions between the alleles of two or more loci, undergoing different evolutionary paths in the two speciating groups, lead to the fitness costs of hybridization.

c. Changes in the numbers of chromosomes cause hybrid zygotes to have lower fitness and often makes them infertile.

d. Two species develop strong prezygotic mechanisms of reproductive isolation and mating is less likely to proceed.

Answer 1

The Dobzhansky-Muller model explains hybrid infertility between close species as a result of epistatic interactions between alleles of different loci.

Step-by-step explanation:

The Dobzhansky-Muller model explains hybrid infertility in crosses between two close species.

It posits that epistatic interactions between the alleles of two or more loci, undergoing different evolutionary paths in the two speciating groups, lead to the fitness costs of hybridization.