The frequency of an allele in a population of Drosophila melanogaster changes haphazardly over time, sometimes going up and sometimes going down.In this population, 17 percent had the allele in 1998 and 30 percent had it in 2016.Biologists found no effect of this allele (versus the other alleles in the population) on any phenotypic trait.What is the best explanation for this pattern?
A) The allele is a neutral allele whose frequency is affected by genetic drift.
B) The allele is a neutral allele whose frequency is affected by stabilizing selection.
C) The allele is undergoing Muller's ratchet.
D) The allele is experiencing frequency-dependent selection, and its frequency should decline.
E) The allele is experiencing frequency-dependent selection, and its frequency should increase.

Question

Quizplus · Accepted Answer

The fact that the allele has no effect on any phenotypic trait suggests that it is a neutral allele, meaning it does not confer any advantage or disadvantage to individuals carrying it. Therefore, its frequency changes are likely due to genetic drift, or random fluctuations in allele frequencies over time.

The Frequency of an Allele in a Population of Drosophila