Question

1. High values of Fst indicate little genetic variation in a local population relative to the total population. In other words, there is high population differentiation (low gene flow). True or false?
2. Which of the following is FALSE of Fst?

1. It will increase with increased isolation.
2. It is can be used as a distance measure.
3. mutation and gene flow
4. mutation and genetic drift

3. _________ decreases genetic variability BETWEEN local populations while _________ has the opposite effect, while also decreasing genetic variability WITHIN local populations.

1. natural selection; assortative mating
2. natural selection; gene flow
3. gene flow; genetic drift

4. Which of the following populations is NOT in HWE?

1. a population undergoing natural selection
2. p² + 2pq + q² = 1
3. a population in which the allele frequencies do not change over time

Answer 1

Please find the answers below:

Answer 1: Choice B (a sub-population can be isolated from the parent population irrespective of its distance, such as separated by natural structures/formations like mountains/lakes etc. Thus, Fst is not indicative of linear distance)

Answer 2: Choice a (While natural selection chooses the best genotype for survival, assortative mating allows decrease in genetic variability due to the accumulation of similar alleles)

Answer 3: Choice A (As one of the major conditions of HWE, a population cannot undergo natural selection, mutation, migration or other forces of evolution)

Answer 2

Question 1

Answer: Wrong.

Analysis: A high Fst value indicates that the genetic variation of the local population is greater than that of the overall population, which means that the population differentiation is high (low gene flow). Because Fst measures the degree of genetic differentiation between populations, the higher the value, the greater the difference between populations, that is, the genetic difference between the local population and the overall population is large, not that the genetic variation is small.

Question 2

Answer: C.

Analysis:

Option A: As the degree of isolation increases, the gene exchange between populations decreases, the genetic differentiation increases, and Fst will gradually increase. This option is correct.

Option B: Fst can reflect the genetic distance between populations and can be used as a distance measurement indicator. This option is correct.

- Option C: Fst mainly reflects the genetic differentiation between populations. Mutations will increase genetic variation, but they are not the factors that directly determine Fst; gene flow will reduce genetic differentiation between populations, not as stated in the option, so this option is wrong.

- Option D: Mutation increases genetic variation, and genetic drift causes random changes in allele frequencies in small populations, increasing differences between populations. Both affect Fst, so this option is correct.

Question 3

Answer: b.

Analysis:

- Natural selection increases the frequency of genes that are suitable for the environment, reduces those that are not suitable, and reduces the genetic variability between local populations.

- Gene flow is the exchange of genes between populations, which introduces new genes, increases the genetic variability within local populations, and reduces the genetic differences between populations, which has the opposite effect of natural selection.

- Selective mating mainly affects the genotype frequency within a population; genetic drift is a random change in gene frequency in a small population, which usually does not reduce the genetic variability between populations. So choose b.

Question 4

Answer: A.

Analysis:

- Option A: Hardy-Weinberg equilibrium (HWE) requires that the population does not undergo natural selection, has no mutation, no gene flow, random mating, and is large enough. Populations undergoing natural selection do not meet the HWE conditions.

Option B: \(p^{2}+2pq + q^{2}=1\) is the genotype frequency formula of Hardy-Weinberg equilibrium, which satisfies HWE.

-Option C: The allele frequency does not change over time, which meets the condition of stable allele frequency in Hardy-Weinberg equilibrium.