Question

You mate a male donkey and a female horse and obtain a mule. Mules are hard working, but usually sterile. What mechanisms separate gene flow between donkeys and horses?

a. prezygotic mechanisms
b. postzygotic mechanisms
c. isozygotic mechanisms
d. none, they will eventually become a single species

Answer 1

Prezygotic barriers and postzygotic barriers prevent gene flow between donkeys and horses, resulting in the sterility of mules.

Step-by-step explanation:

Prezygotic barriers and postzygotic barriers prevent gene flow between donkeys and horses. Prezygotic mechanisms act before fertilization and include gametic barriers, such as differences in eggs and sperm that prevent fertilization from taking place. Additionally, in some cases, reproductive structures may not fit together, preventing successful mating.

On the other hand, postzygotic mechanisms occur after fertilization and can result in genetic incompatibilities that hinder proper development of the offspring. In the specific example of mating a male donkey and a female horse, the resulting mule is usually sterile, meaning it cannot produce viable gametes.