Question 1

Which of the following best describes genetic migration in a population genetics context?

Accepted Answer

The movement of alleles from one population to another, altering allele frequencies.

Question 2

A population of rabbits has an allele frequency for allele A ($$p_1) of 0.7. A $$neighboring population has $$p_2 = 0.2$. If the migration rate (m$) is 0.1, what is the new allele frequency (p_1$') in $$the first population after migration? Use the formula $$p_1$$' = $$p_1 + m$$($$p_2$$ - $$p_1$$)$$.

Accepted Answer

$$p_1$$' = 0.7 + 0.1(0.2 - 0.7) = 0.7 - 0.05 = 0.65$$

Question 3

Which factor does NOT directly affect the proportion of alleles in a population after migration?

Accepted Answer

Mutation rate within the population

Question 4

A researcher finds that after migration, the allele frequency in a population is $$p_1$$' = 0.45$$. If p_1$ = 0.62$$, $$p_2 = 0.03$, use the formula m$$ = \frac{$$p_1$$' - $$p_1$$}{$$p_2$$ - $$p_1$$}$$ to calculate the migration rate.

Accepted Answer

$$m = \frac{0.45 - 0.62}{0.03 - 0.62} = \frac{-0.17}{-0.59} \approx 0.288$$

Question 5

Which of the following is an example of artificial selection?

Accepted Answer

Farmers breeding cows for higher milk production.

Question 6

In the context of selection, what does 'fitness' refer to?

Accepted Answer

The ability of an individual to survive and reproduce, contributing offspring to the next generation.

Question 7

Most mutant alleles are recessive to wild type. Under what condition can a mutant allele persist in a population?

Accepted Answer

If heterozygotes have fitness levels at or above the wild type.

Question 8

Given the following fitness values for genotypes: $$w_{AA} = 1$$, $$w_{Aa} = 1 - s_1$, w$$_{aa} = 1 - $$s_2$$, which genotype is most likely to increase in frequency if $$s_1$$ and $$s_2$$ are both positive?

Accepted Answer

AA

Question 9

A population starts with $$p = 0.9$$ for allele A and $$q = 0.1$$ for allele a. After selection, $$p = 0.908. $$What is the change in allele frequency ($$\Delta p$$)?

Accepted Answer

$$\Delta p = 0.908 - 0.9 = 0.008$$

Question 10

Which scenario best illustrates a genetic bottleneck?

Accepted Answer

A small number of individuals survive a natural disaster, drastically reducing genetic diversity.

Question 11

If the fitness of the heterozygote ($$Aa) is$$ $$1 - s_1$ and the fitness of the homozygous recessive (aa$) is 1$$ - $$s_2$$, what is the formula for the frequency of allele A after selection, given $$p_0$$ and $$q_0 as $$initial frequencies?

Accepted Answer

$$p_1$$ = \frac{$$p_0(1$$ - $$s_1$$ $$q_0$$)}{1 - 2s_1 $$p_0$$ $$q_0$$ - $$s_2$$ $$q_0^2$$}$$

Question 12

Suppose $$p_0 = 0.6$, q_0$ = 0.4$$, $$s_1 = 0.25$, and s_2$ = 0.50. $$Using the formula $$p_1$$ = \frac{$$p_0(1$$ - $$s_1$$ $$q_0$$)}{1 - 2s_1 $$p_0$$ $$q_0$$ - $$s_2$$ $$q_0^2$$}$$, what is p_1$?

Accepted Answer

$$p_1$$ = \frac{0.6(1 - 0.25 	imes 0.4)}{1 - 2 	imes 0.25 	imes 0.6 	imes 0.4 - 0.5 	imes 0.16} = \frac{0.6 	imes 0.9}{1 - 0.12 - 0.08} = \frac{0.54}{0.8} = 0.675$$

Question 13

Which of the following is NOT a possible outcome of natural selection?

Accepted Answer

Artificial selection for productivity

Question 14

A population of squirrels is all black ($$f(B) = 1). A $$researcher releases gray squirrels ($$f(B) = 0$$, $$f(b) = 1) so $$that they make up 5% of the final population. What is the frequency of the gray allele, $$b$$, after migration?

Accepted Answer

$$q_1$$' = 1 - $$p_1$$' = 0.05$$, so f(b$$)' = 0.05$$

Question 15

Which of the following best explains why artificial selection can lead to rapid changes in a population compared to natural selection?

Accepted Answer

Artificial selection is goal-oriented and directed by humans, while natural selection is driven by environmental pressures.

Question 16

If a population experiences a high rate of migration from another population with very different allele frequencies, what is the most likely genetic outcome?

Accepted Answer

The allele frequencies in the recipient population will shift toward those of the migrant population.

Question 17

Which of the following statements about fitness is TRUE?

Accepted Answer

Fitness is an aspect of phenotype and determines reproductive success.

Question 18

In a selection scenario where $$AA is $$the preferred genotype, which formula gives the frequency of allele $$A$$ after selection?

Accepted Answer

$$p_1$$ = \frac{$$p_0(1$$ - $$s_1$$ $$q_0$$)}{1 - 2s_1 $$p_0$$ $$q_0$$ - $$s_2$$ $$q_0^2$$}$$

Population Genetics: Migration and Selection

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