A researcher examines a microsatellite locus in a wild population of D. melanogaster. She finds that in a sample of 50 individuals, 20 different alleles are segregating. According to the neutral theory, these alleles are most likely experiencing
A) balancing selection.
B) directional selection.
C) genetic drift.
D) neutral selection.

Question

Quizplus · Accepted Answer

Genetic drift is a mechanism of evolution that refers to random changes in the frequencies of alleles within a population. In the context of the neutral theory, which posits that most genetic variation is due to the accumulation of neutral mutations that do not affect an organism's fitness, the presence of 20 different alleles segregating in a small sample of a population suggests that these alleles are likely not under strong selective pressure. Instead, their presence and frequencies are more likely to be influenced by genetic drift, which can have a significant impact in small populations, leading to the random fluctuation of allele frequencies over time.

A Researcher Examines a Microsatellite Locus in a Wild Population