BIOA01 – Module 1
Exam-Style Practice Problems: Population Genetics & Hardy–Weinberg
Instructions. Show all work for full credit. Unless otherwise stated, assume a diploid, auto-
somal locus with two alleles A and a in a large population with non-overlapping generations.
Part A — Multiple Choice (Best Answer)
A1. In a population at Hardy–Weinberg equilibrium (HWE) for a bi-allelic locus, which state-
ment must be true? [3
pts]
(a) Genotype frequencies stay constant, but allele frequencies change.
(b) Both allele and genotype frequencies remain constant across generations.
(c) Allele frequencies stay constant, but genotype frequencies change.
(d) Heterozygotes have the highest fitness.
A2. Which of the following violates HWE assumptions? [3 pts]
(a) Random mating within a large population.
(b) No selection on the locus.
(c) Bidirectional mutation between A and a at equal rates.
(d) No migration.
A3. If p = 0.7 at an autosomal locus under HWE, the expected heterozygote frequency is: [3
pts]
(a) 0.72 = 0.49
(b) 2(0.7)(0.3) = 0.42
(c) 0.32 = 0.09
(d) 0.7 + 0.3 = 1.0
A4. In a very small population after a severe bottleneck, which force most likely dominates
allele-frequency change at a neutral locus? [3 pts]
(a) Mutation
(b) Gene flow
(c) Genetic drift
(d) Overdominance
1
Exam-Style Practice Problems: Population Genetics & Hardy–Weinberg
Instructions. Show all work for full credit. Unless otherwise stated, assume a diploid, auto-
somal locus with two alleles A and a in a large population with non-overlapping generations.
Part A — Multiple Choice (Best Answer)
A1. In a population at Hardy–Weinberg equilibrium (HWE) for a bi-allelic locus, which state-
ment must be true? [3
pts]
(a) Genotype frequencies stay constant, but allele frequencies change.
(b) Both allele and genotype frequencies remain constant across generations.
(c) Allele frequencies stay constant, but genotype frequencies change.
(d) Heterozygotes have the highest fitness.
A2. Which of the following violates HWE assumptions? [3 pts]
(a) Random mating within a large population.
(b) No selection on the locus.
(c) Bidirectional mutation between A and a at equal rates.
(d) No migration.
A3. If p = 0.7 at an autosomal locus under HWE, the expected heterozygote frequency is: [3
pts]
(a) 0.72 = 0.49
(b) 2(0.7)(0.3) = 0.42
(c) 0.32 = 0.09
(d) 0.7 + 0.3 = 1.0
A4. In a very small population after a severe bottleneck, which force most likely dominates
allele-frequency change at a neutral locus? [3 pts]
(a) Mutation
(b) Gene flow
(c) Genetic drift
(d) Overdominance
1
