Q: A population of 200 lizards has the following genotype counts: AA: 98, Aa: 84, aa: 18. What is the observed frequency of allele a?

$$q = \frac{2 \times 18 + 84}{2 \times 200} = 0.3$$

Q: If a population is in Hardy-Weinberg equilibrium and the frequency of allele a ($$q) is$$ $$0.3$$, what is the expected frequency of heterozygotes ($$Aa$$)?

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Q: A rare genetic disorder is caused by a recessive allele. In a population of 10,000, 9 individuals are affected. Assuming Hardy-Weinberg equilibrium, what is the carrier frequency?

$$2pq \approx 2 \times 0.03 \times 0.97 = 0.058 or$$ $$5.8\%$$

Q: If the frequency of a recessive disease in a population is $$q^2 = 0.00025$, what is the frequency of carriers (heterozygotes) under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.0158 \times 0.9842 = 0.0311$$

Q: A population of 300 beetles has genotype frequencies: BB: 0.49, Bb: 0.42, bb: 0.09. What is the frequency of allele B?

$$p = 0.49 + 0.5 \times 0.42 = 0.7$$

Question 1

Which of the following is a key assumption of the Hardy-Weinberg equilibrium that, if violated, can lead to changes in allele frequencies in a population?

Accepted Answer

All of the above.

Question 2

In a population of 100 dogs, the following genotypes are observed: AA: 12, Aa: 28, aa: 60. What is the frequency of allele A in this population?

Accepted Answer

$$0.2$$

Question 3

Which equation correctly represents the relationship between allele frequencies in a population with two alleles, A and a?

Accepted Answer

$$p + q = 1$$

Question 4

A population of 200 lizards has the following genotype counts: AA: 98, Aa: 84, aa: 18. What is the observed frequency of allele a?

Accepted Answer

$$q = \frac{2 	imes 18 + 84}{2 	imes 200} = 0.3$$

Question 5

If a population is in Hardy-Weinberg equilibrium and the frequency of allele a ($$q) is$$ $$0.3$$, what is the expected frequency of heterozygotes ($$Aa$$)?

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 6

A rare genetic disorder is caused by a recessive allele. In a population of 10,000, 9 individuals are affected. Assuming Hardy-Weinberg equilibrium, what is the carrier frequency?

Accepted Answer

$$2pq \approx 2 	imes 0.03 	imes 0.97 = 0.058 or$$ $$5.8\%$$

Question 7

Which of the following best explains why dominant alleles do not necessarily increase in frequency over time in a population?

Accepted Answer

Hardy-Weinberg equilibrium predicts allele frequencies remain constant in the absence of evolutionary forces.

Question 8

A population of beetles has genotype frequencies: BB: 0.36, Bb: 0.48, bb: 0.16. Is this population in Hardy-Weinberg equilibrium?

Accepted Answer

Yes, because $$p^2 = 0.36$, 2pq = 0.48$, q^2$ = 0.16$$ and $$p + q = 1.$$

Question 9

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

Accepted Answer

Mutation rate is high.

Question 10

In a population, the frequency of the CCR5-Δ32 allele is 0.11. Assuming Hardy-Weinberg equilibrium, what is the expected frequency of individuals homozygous for CCR5-Δ32?

Accepted Answer

$$q^2$$ = $$(0.11)^2 = 0.0121$

Question 11

A population of flies has genotype frequencies: AA: 0.36, Aa: 0.48, aa: 0.16. If the population is in Hardy-Weinberg equilibrium, what will be the frequency of the aa genotype in the next generation?

Accepted Answer

$$q^2$$ = $$(0.4)^2 = 0.16$

Question 12

Which of the following scenarios would most likely cause a population to deviate from Hardy-Weinberg equilibrium?

Accepted Answer

Natural selection favoring one genotype.

Question 13

If the frequency of a recessive disease in a population is $$q^2 = 0.00025$, what is the frequency of carriers (heterozygotes) under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.0158 	imes 0.9842 = 0.0311$$

Question 14

Which of the following best describes the gene-counting method for determining allele frequencies?

Accepted Answer

It requires knowing the genotypes of all individuals and sums the homozygotes plus half the heterozygotes.

Question 15

A population of 300 beetles has genotype frequencies: BB: 0.49, Bb: 0.42, bb: 0.09. What is the frequency of allele B?

Accepted Answer

$$p = 0.49 + 0.5 	imes 0.42 = 0.7$$

Question 16

Which of the following is a consequence of Hardy-Weinberg equilibrium?

Accepted Answer

Genetic variation can be maintained in a population over time.

Question 17

If a population is not in Hardy-Weinberg equilibrium, what does this indicate?

Accepted Answer

At least one Hardy-Weinberg assumption is being violated.

Question 18

In a population, the observed genotype frequencies are AA: 0.25, Aa: 0.50, aa: 0.25. What are the allele frequencies?

Accepted Answer

$$p = 0.25 + 0.5 	imes 0.5 = 0.5$$, $$q = 0.25 + 0.5 	imes 0.5 = 0.5$$

Question 19

Which of the following real-world examples demonstrates the maintenance of genetic variation in a population as predicted by Hardy-Weinberg equilibrium?

Accepted Answer

Both black and white peppered moths persist in a population with no selection pressure.

Hardy-Weinberg Equilibrium: Principles, Calculations, and Applications

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