Exam 6: The Ways of Change: Drift and Selection

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 ten 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, while for the other half she randomly selects 200 flies to transfer. After ten 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, 0.35 Treatment 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 ​ What is a plausible explanation for the differences between the treatments? Please make sure to explain your logic.

Which of the following is an example of the founder effect?

Please describe two factors that would increase the likelihood of fixing a beneficial allele in a population of finite size.

Over the same landscape, populations may differ in degree of subdivision depending on their movement. Which of the following is/are true?

Mutations in the GDF9 gene in sheep have been linked to changes in female fecundity. The following are the relative fitnesses of different genotypes in the population. Which statement below is correct? Genotype Relative fitness +/ -           1 +/ +           0.7 -/ -           0.1

Explain the four assumptions of the Hardy-Weinberg theorem.

The effectiveness of selection on an allele depends in part on

Which of the following is true regarding the relative importance of drift and selection?

In a population of infinite size, which statement accurately describes the eventual fate of a new beneficial allele?

In the Hardy-Weinberg equation, p² is

In a population of ground beetles, a genetic locus that codes for setae on the elytra has two variants: G is dominant and codes for setae on the elytra, and g is recessive and codes for glabrous elytra (no setae). If the frequency of beetles with glabrous elytra is 0.36, what is the frequency of the G allele, assuming the population is in Hardy-Weinberg equilibrium?

Which of the following scientific disciplines does not fall under the purview of landscape genetics?

Which of the following would be a useful proxy for fitness?

Which of the following is/are correct regarding the different types of alleles?

Which of the following is/are true regarding genetic distance among populations?

Genetic drift

Considering the principles of mutation, natural selection, and genetic drift, do you expect adaptive evolution to occur more rapidly in small or large populations? What about nonadaptive evolution? For each answer, please explain your reasoning.

Inbreeding results in a higher frequency of ________ in a population. Inbreeding depression occurs because _______.

The graph below depicts the change in frequency for an advantageous allele in two different populations, both of infinite size. The strength of selection is the same in both populations. (a) What type of allele is this? Explain how you know. (b) Why does the frequency of the allele in one of the populations rise faster than the frequency in the other population? (c) If given enough time, will the allele become fixed in each of these populations?

Which of the following would likely increase the likelihood of fixing a beneficial allele in a population of finite size?