Q: A population of 3100 people has 1101 MM, 1496 MN, and 503 NN for the MN blood group. What is the observed frequency of the M allele?

$$p = \frac{(2 \times 1101) + 1496}{2 \times 3100} = 0.60$$

Q: In a population of 100 flowers, 64 are RR, 32 are Rr, and 4 are rr. What is the observed frequency of the r allele?

$$r = \frac{32 + 2 \times 4}{2 \times 100} = \frac{40}{200} = 0.2$$

Question 1

Which of the following best describes a gene pool in population genetics?

Accepted Answer

All the alleles for a gene present in a population of a given species.

Question 2

In a population of 100 cats, 84 are black (dominant, B) and 16 are white (recessive, b). Assuming Hardy-Weinberg equilibrium, what is the frequency of the b allele?

Accepted Answer

$$q = \sqrt{0.16} = 0.4$$

Question 3

Which mechanism is primarily responsible for introducing new genetic variation into a population?

Accepted Answer

Mutation

Question 4

A population of 3100 people has 1101 MM, 1496 MN, and 503 NN for the MN blood group. What is the observed frequency of the M allele?

Accepted Answer

$$p = \frac{(2 	imes 1101) + 1496}{2 	imes 3100} = 0.60$$

Question 5

Which of the following is NOT an assumption of the Hardy-Weinberg equilibrium?

Accepted Answer

Natural selection is acting on the trait

Question 6

In a population, the frequency of the i allele (O blood type) is 0.38 and the frequency of the IB allele is 0.11. What is the expected frequency of the AB blood type (IAIB) under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2(0.51)(0.11) = 0.1122$$

Question 7

Which evolutionary mechanism is most likely responsible for the high frequency of Ellis-van Creveld syndrome in the Amish population?

Accepted Answer

Founder effect

Question 8

A population of 200 males has 48 individuals with an X-linked recessive condition. What is the frequency of the recessive allele (q)?

Accepted Answer

$$q = \frac{48}{200} = 0.24$$

Question 9

Which of the following best explains why genetic drift has a larger effect on small populations?

Accepted Answer

Chance events can cause large changes in allele frequencies due to fewer individuals.

Question 10

In a population of 100 flowers, 64 are RR, 32 are Rr, and 4 are rr. What is the observed frequency of the r allele?

Accepted Answer

$$r = \frac{32 + 2 	imes 4}{2 	imes 100} = \frac{40}{200} = 0.2$$

Question 11

Which of the following scenarios is an example of gene flow?

Accepted Answer

A bee carries pollen from one flower population to another, introducing new alleles.

Question 12

If the frequency of a recessive genotype (ff) in a population is 0.09, what is the expected frequency of heterozygotes (Ff) under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2(0.7)(0.3) = 0.42$$

Question 13

Which of the following is a consequence of a genetic bottleneck?

Accepted Answer

Reduced genetic variation and possible fixation of harmful alleles.

Question 14

In a population, the frequency of the IA allele is 0.27, IB is 0.06, and i is 0.67. What is the expected frequency of blood type A (IAIA or IAi)?

Accepted Answer

$$p^2 + 2pr$$ = $$(0.27)^2 + 2(0.27)(0.67) = 0.0729 + 0.3618 = 0.4347$

Question 15

Which of the following best describes the effect of heterozygote advantage in a population?

Accepted Answer

Heterozygotes have higher fitness, maintaining both alleles in the population.

Question 16

A population of 283 individuals has 223 CCR5/CCR5, 57 CCR5/Δ32, and 3 Δ32/Δ32. What is the frequency of the Δ32 allele?

Accepted Answer

$$q = \frac{2 	imes 3 + 57}{2 	imes 283} = \frac{6 + 57}{566} = 0.111$$

Question 17

Which of the following is a correct application of the Hardy-Weinberg equation for a two-allele system?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 18

Which of the following is an example of non-random mating?

Accepted Answer

Individuals preferentially mate with others that have similar phenotypes.

Question 19

In a population, 10% of males are colorblind (X-linked recessive). What is the expected frequency of colorblind females under Hardy-Weinberg equilibrium?

Accepted Answer

$$q^2$$ = $$(0.1)^2 = 0.01$

Population Genetics and the Hardy-Weinberg Principle

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