PCB 4674: Human Evolutionary Genetics Final Exam
Questions & Answers | Grade A | 100% Correct –
Florida State University
1. Which of the following assumptions is NOT required for a population to be in
Hardy-Weinberg equilibrium?
A. Infinite population size
B. No mutation or migration
C. Non-random mating
D. No natural selection
Answer: C
Explanation: Hardy-Weinberg equilibrium assumes random mating. Non-random mating,
such as assortative mating or inbreeding, changes genotype frequencies but not necessarily
allele frequencies.
2. In a small population, what is the primary cause of changes in allele
frequencies over generations?
A. Natural selection
B. High mutation rate
C. Genetic drift
D. Gene flow
Answer: C
Explanation: Genetic drift is the random fluctuation of allele frequencies due to chance,
which is much more pronounced in small populations.
,3. Which statistic is most commonly used to measure the proportion of genetic
variation that is found between populations?
A. Fst (Fixation Index)
B. Nucleotide diversity (pi)
C. Tajima’s D
D. Linkage disequilibrium (LD)
Answer: A
Explanation: Fst measures population differentiation based on genetic polymorphisms;
higher values indicate greater divergence between populations.
4. Why is mitochondrial DNA (mtDNA) a useful tool for tracing maternal
lineages?
A. It undergoes frequent recombination
B. It has a very slow mutation rate
C. It is inherited uniparentally from the mother
D. It contains the majority of a cell’s genetic information
Answer: C
Explanation: Mitochondrial DNA is passed from mother to offspring without
recombination, allowing the tracing of maternal ancestry back many generations.
5. The ‘Out of Africa’ model of human origins is best supported by which genetic
observation?
A. Greater linkage disequilibrium in African populations
B. Higher genetic diversity in African populations compared to non-African populations
C. Significant Neanderthal DNA in all global populations
D. Equal distribution of rare alleles across all continents
Answer: B
, Explanation: The highest level of genetic diversity is found within Africa, which is
consistent with the bottleneck effect that occurred when a subset of the population
migrated out of Africa.
6. Which hominin species is famous for the specimen ‘Lucy’ and lived
approximately 3.2 million years ago?
A. Australopithecus afarensis
B. Homo habilis
C. Ardipithecus ramidus
D. Homo erectus
Answer: A
Explanation: Lucy belongs to Australopithecus afarensis, a species that exhibits both
bipedal characteristics and ape-like cranial features.
7. What does a negative Tajima’s D value typically indicate about a population?
A. Population contraction or balancing selection
B. High levels of inbreeding
C. Genetic stability and neutrality
D. Recent population expansion or positive selection
Answer: D
Explanation: A negative Tajima’s D indicates an excess of rare variants, which is
characteristic of a population that has recently expanded in size or experienced a selective
sweep.
Questions & Answers | Grade A | 100% Correct –
Florida State University
1. Which of the following assumptions is NOT required for a population to be in
Hardy-Weinberg equilibrium?
A. Infinite population size
B. No mutation or migration
C. Non-random mating
D. No natural selection
Answer: C
Explanation: Hardy-Weinberg equilibrium assumes random mating. Non-random mating,
such as assortative mating or inbreeding, changes genotype frequencies but not necessarily
allele frequencies.
2. In a small population, what is the primary cause of changes in allele
frequencies over generations?
A. Natural selection
B. High mutation rate
C. Genetic drift
D. Gene flow
Answer: C
Explanation: Genetic drift is the random fluctuation of allele frequencies due to chance,
which is much more pronounced in small populations.
,3. Which statistic is most commonly used to measure the proportion of genetic
variation that is found between populations?
A. Fst (Fixation Index)
B. Nucleotide diversity (pi)
C. Tajima’s D
D. Linkage disequilibrium (LD)
Answer: A
Explanation: Fst measures population differentiation based on genetic polymorphisms;
higher values indicate greater divergence between populations.
4. Why is mitochondrial DNA (mtDNA) a useful tool for tracing maternal
lineages?
A. It undergoes frequent recombination
B. It has a very slow mutation rate
C. It is inherited uniparentally from the mother
D. It contains the majority of a cell’s genetic information
Answer: C
Explanation: Mitochondrial DNA is passed from mother to offspring without
recombination, allowing the tracing of maternal ancestry back many generations.
5. The ‘Out of Africa’ model of human origins is best supported by which genetic
observation?
A. Greater linkage disequilibrium in African populations
B. Higher genetic diversity in African populations compared to non-African populations
C. Significant Neanderthal DNA in all global populations
D. Equal distribution of rare alleles across all continents
Answer: B
, Explanation: The highest level of genetic diversity is found within Africa, which is
consistent with the bottleneck effect that occurred when a subset of the population
migrated out of Africa.
6. Which hominin species is famous for the specimen ‘Lucy’ and lived
approximately 3.2 million years ago?
A. Australopithecus afarensis
B. Homo habilis
C. Ardipithecus ramidus
D. Homo erectus
Answer: A
Explanation: Lucy belongs to Australopithecus afarensis, a species that exhibits both
bipedal characteristics and ape-like cranial features.
7. What does a negative Tajima’s D value typically indicate about a population?
A. Population contraction or balancing selection
B. High levels of inbreeding
C. Genetic stability and neutrality
D. Recent population expansion or positive selection
Answer: D
Explanation: A negative Tajima’s D indicates an excess of rare variants, which is
characteristic of a population that has recently expanded in size or experienced a selective
sweep.
