Q: If a population has allele frequencies $$p = 0.7$$ and $$q = 0.3$$, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

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

Q: In a population of 3005 geese, 2524 are blue (BB or Bb) and 481 are white (bb). Assuming Hardy-Weinberg equilibrium, how many blue geese are expected to be heterozygotes (Bb)?

$$Bb = 0.48 \times 3005 = 1442$$

Q: In a population, the frequency of allele $$A is$$ $$p = 0.4$$ and allele $$a is$$ $$q = 0.6. $$What is the expected frequency of $$Aa$$ individuals after one generation of random mating?

$$2pq = 2 \times 0.4 \times 0.6 = 0.48$$

Question 1

Which of the following best describes the Hardy-Weinberg equilibrium principle?

Accepted Answer

It predicts that allele and genotype frequencies will remain constant from generation to generation in the absence of evolutionary forces.

Question 2

A population of geese has 481 white individuals (genotype bb) out of 3005 total. Assuming Hardy-Weinberg equilibrium, what is the frequency of the b allele ($$q$$)?

Accepted Answer

$$q = \sqrt{\frac{481}{3005}} = 0.4$$

Question 3

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

Accepted Answer

There is a high mutation rate.

Question 4

If a population has allele frequencies $$p = 0.7$$ and $$q = 0.3$$, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

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

Question 5

Which evolutionary force is most likely responsible for unpredictable changes in allele frequencies in small populations?

Accepted Answer

Genetic drift

Question 6

In a population of 1000 individuals, the genotype frequencies are: $$AA = 0.36$$, $$Aa = 0.48$$, $$aa = 0.16. $$What are the allele frequencies of $$A$$ and $$a$$?

Accepted Answer

$$p = 0.6$$, $$q = 0.4$$

Question 7

A population of flies is exposed to ethanol. Over several generations, the frequency of the AdhF allele increases. Which Hardy-Weinberg assumption is being violated?

Accepted Answer

No selection

Question 8

If the observed genotype frequencies in a population deviate significantly from those expected under Hardy-Weinberg equilibrium, what can you conclude?

Accepted Answer

At least one of the Hardy-Weinberg assumptions is being violated.

Question 9

Given a population with $$p = 0.5$$ and $$q = 0.5$$, what is the expected frequency of homozygous recessive individuals ($$aa) $$under Hardy-Weinberg equilibrium?

Accepted Answer

$$q^2$$ = $$(0.5)^2 = 0.25$

Question 10

A chi-square test is used to compare observed and expected genotype frequencies. If the calculated $$\$$chi^2$$ value is greater than the critical value at p = 0.05$, what is the correct interpretation?

Accepted Answer

Reject the null hypothesis; the population is not in Hardy-Weinberg equilibrium.

Question 11

In a population of 3005 geese, 2524 are blue (BB or Bb) and 481 are white (bb). Assuming Hardy-Weinberg equilibrium, how many blue geese are expected to be heterozygotes (Bb)?

Accepted Answer

$$Bb = 0.48 	imes 3005 = 1442$$

Question 12

Which of the following scenarios would violate the assumption of random mating in Hardy-Weinberg equilibrium?

Accepted Answer

Individuals preferentially mate with others of the same genotype.

Question 13

If a population is in Hardy-Weinberg equilibrium and $$p = 0.8$$, what is the expected frequency of the $$AA$$ genotype?

Accepted Answer

$$p^2$$ = $$(0.8)^2 = 0.64$

Question 14

Which of the following best explains why genetic drift has a stronger effect in small populations?

Accepted Answer

Random sampling error is greater in small populations, leading to larger fluctuations in allele frequencies.

Question 15

In a population, the frequency of allele $$A is$$ $$p = 0.4$$ and allele $$a is$$ $$q = 0.6. $$What is the expected frequency of $$Aa$$ individuals after one generation of random mating?

Accepted Answer

$$2pq = 2 	imes 0.4 	imes 0.6 = 0.48$$

Question 16

A population of plants has the following genotype counts: 10 RR, 10 RB, and 30 BB. What is the chi-square statistic for testing Hardy-Weinberg equilibrium if the expected counts are 4.5 RR, 21 RB, and 24.5 BB?

Accepted Answer

$$\$$chi^2$$ = \frac{(10-4.5)^2$}{4.5} + \frac{(10-21)^2$}{21} + \frac{(30-24.5)^2$}{24.5} = 13.71$$

Question 17

Which of the following is a real-world example of selection changing allele frequencies in a population?

Accepted Answer

The increase in frequency of the AdhF allele in fruit flies exposed to ethanol.

Question 18

If a population is not in Hardy-Weinberg equilibrium, which of the following could be a possible cause?

Accepted Answer

Selection, mutation, migration, genetic drift, or non-random mating

Question 19

In a malaria season, the observed genotype frequencies in babies are significantly different from Hardy-Weinberg expectations. What does this suggest?

Accepted Answer

Selection is acting on the population.

Mendelian Genetics in Populations I: Selection and Mutation

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