Question

6. A researcher performs an experiment on fruit flies to monitor the change in allele frequency of an allele called “A.” She starts with 24 populations, each with an initial starting frequency for A of 0.5. Flies are maintained for 10 generations by transferring the offspring from each generation to a new vial, where they produce the next generation. For half of the populations she randomly selects 20 flies to transfer (treatment 1), while for the other half she randomly selects 200 flies to transfer. After 10 generations she collects the following allele frequency data:Treatment 1: 0.55, 0.6, 0.2, 0.9, 0.45, 0.35, 0.1, 0.65, 0.65. 0.55, 0.75, 0.35Treatment 2: 0.85, 0.8, 0.75, 0.8, 0.75, 1.0, 0.8, 0.85, 0.9, 0.8, 0.85, 0.8 Describe a plausible explanation for the differences between the treatments? Please make sure to explain your logic. (40 pts)

Answer 1

Describe a plausible explanation for the differences between the treatments?

Considering the fact that the allele increased in frequency in all replicates of the treatment two, we can presume that this allele is beneficial. In treatment one, even though the allele is beneficial, it increases in some replicates but not in all replicates. This discrepancy can be explained by the fact that treatment one had a smaller population size transferred each generation. As a result, the drift was strong. Since it is a random process, the allele frequency is fluctuated more or less randomly.