Question

some individuals of a population of raccoons in a mangrove forest mate in may, while other individuals mate in june. raccoons in the next generation seem to mate in the month that they were conceived. a new mutation, causing a recessive genetic disease, shows up in a few of the raccoons that reproduce in may but none of the raccoons that reproduce in june. which of the following is a possible outcome for the disease allele?

the disease allele will not spread in the may nor the june mating populations.

the disease allele may spread among the raccoons that mate in may but will not spread to those that mate in june.

the disease allele may spread among the raccoons that mate in june but will not spread to those that mate in may.

the disease allele may spread among the raccoons that mate in may and those that mate in june.

Explanation:

The raccoons that mate in May and June are reproductively isolated (temporal isolation, as they mate at different times). The mutation (recessive disease allele) is in the May - mating population. Since the June - mating raccoons don't interbreed with the May - mating ones (because they mate in different months, and offspring mate in the month of conception), the allele can spread within the May - mating population but not to the June - mating population.

Answer:

The disease allele may spread among the raccoons that mate in May but will not spread to those that mate in June.