Question

Two populations of a species of pine tree are located on opposite sides of a mountain range. The two populations are genetically similar to each other.
An invasive beetle infestation kills 80% of the trees on the west side of the range. The beetle population does not spread to the eastern side of the range, and the east tree population does not experience any beetle related loss. After the infestation, the western tree population increases in size again.
What is the expected outcome of genetic testing comparing the two populations?

• A. The genetic diversity of the west population is higher than the east population.
• B. The phenotypic variation of the west population is higher than the east population.
• C. The two populations are less genetically similar than they were prior to the beetle infestation.
• D. The two populations remain genetically similar.

Answer 1

The correct option is C The two populations are less genetically similar than they were prior to the beetle infestation.

Due to beetle infestation, 80% of the trees on the west side of the range were killed. This will result in the alteration of allele frequencies. Certain alleles are lost during infestation. In the small population of the west side, genetic diversity is less compared to that of a large population in the east. Due to less genetic diversity, phenotypic variations will also be lower on the west side. Hence, the two side of populations will be less genetically similar than the earlier.

Thus, the correct answer is 'The two populations are less genetically similar than they were prior to the beetle infestation.'