Questions on Population Genetics
Multiple-Choice Questions: Population Genetics
1. What is population genetics?
A) Study of individual mutations
B) Study of genetic variation within populations and how it changes over time
C) Study of gene expression in cells
D) Study of ecosystems
E) Study of species extinction
2. What is a gene pool?
A) A group of genes that never mutate
B) All the genes and alleles present in a population
C) A collection of species in an area
D) The genes of one individual
E) Genes responsible for swimming abilities
3. Which term describes the proportion of different alleles in a population?
A) Genetic drift
B) Allele frequency
C) Gene mutation
D) Natural selection
E) Hybridization
4. What is genetic drift?
A) Non-random mating
B) Change in allele frequencies due to chance events
C) Migration of individuals
D) Natural selection based on fitness
E) Mutation in genes
5. Which population is most affected by genetic drift?
A) Large populations
B) Small populations
C) Populations with high mutation rate
D) Populations with no migration
E) All populations equally
6. What is the Hardy-Weinberg principle used for?
A) Predicting genotype frequencies under no evolutionary forces
B) Explaining natural selection
C) Measuring mutation rates
D) Studying gene flow
E) Explaining speciation
7. According to Hardy-Weinberg equilibrium, allele frequencies in a population will remain constant if:
A) Mutation and migration occur frequently
B) Natural selection favors one allele
C) No mutation, no migration, large population, random mating, and no selection
D) Population size is very small
E) Organisms reproduce asexually
8. What is gene flow?
A) Loss of alleles through extinction
B) Movement of alleles between populations
C) Random changes in allele frequency
D) Selection of favorable traits
E) Genetic mutation
9. What effect does gene flow have on populations?
A) Increases genetic differences
B) Reduces genetic differences
C) Has no effect
D) Causes extinction
E) Destroys alleles
10. What is a bottleneck effect?
A) Large population growth
B) Sudden reduction in population size causing loss of genetic variation
C) Migration of individuals
D) Mutation accumulation
E) Increase in mutation rate
11. The founder effect occurs when:
A) A few individuals start a new population with limited genetic diversity
B) Large populations migrate
C) Natural selection increases allele variety
D) Mutation rates increase suddenly
E) Species become extinct
12. Which of the following is an example of natural selection acting on a population?
A) Random mating in a population
B) Higher survival of individuals with advantageous traits
C) Sudden changes in allele frequencies due to chance
D) Migration between populations
E) Mutation rates rising randomly
13. What does heterozygosity refer to?
A) Proportion of individuals with two different alleles at a gene locus
B) Proportion of homozygous individuals
C) Rate of mutation
D) Size of a population
E) Number of alleles in a gene pool
14. How does inbreeding affect genetic variation?
A) Increases genetic variation
B) Decreases genetic variation
C) Has no effect
D) Always leads to new species
E) Randomizes alleles
15. What is the main cause of mutation in populations?
A) Natural selection
B) Genetic drift
C) Errors in DNA replication
D) Migration
E) Gene flow
16. Which factor does NOT cause evolution?
A) Natural selection
B) Genetic drift
C) Gene flow
D) Mutation
E) Random mating
17. What is allele fixation?
A) When all individuals in a population have different alleles
B) When an allele’s frequency reaches 100% in a population
C) When a new mutation occurs
D) When allele frequencies remain balanced
E) When gene flow stops
18. The formula p+q=1p + q = 1p+q=1 in Hardy-Weinberg refers to:
A) Total number of genotypes
B) Total allele frequency of two alleles in a population
C) Population size
D) Mutation rate
E) Fitness level
19. What is the likely effect of a small isolated population on genetic variation?
A) Increase in genetic variation
B) Decrease in genetic variation
C) No change in variation
D) Immediate speciation
E) Loss of all alleles
20. Why is large population size important to maintain genetic variation?
A) Prevents mutation
B) Reduces impact of genetic drift
C) Stops gene flow
D) Encourages inbreeding
E) Fixes alleles immediately
Answer Key with Detailed Explanations
1. B – Population genetics studies how allele frequencies change over time within populations.
2. B – A gene pool consists of all alleles of all genes in a population.
3. B – Allele frequency is the proportion of each allele in the population’s gene pool.
4. B – Genetic drift is random changes in allele frequency, especially impactful in small populations.
5. B – Small populations are more susceptible to genetic drift due to sampling effects.
6. A – Hardy-Weinberg principle predicts allele and genotype frequencies under no evolution.
7. C – The five conditions for Hardy-Weinberg equilibrium must be met to maintain constant allele frequencies.
8. B – Gene flow is movement of alleles between populations through migration.
9. B – Gene flow tends to homogenize populations, reducing genetic differences.
10. B – Bottleneck effect is a drastic reduction in population size reducing genetic variation.
11. A – Founder effect happens when a few individuals establish a new population with limited alleles.
12. B – Natural selection favors individuals with traits that increase survival and reproduction.
13. A – Heterozygosity is the proportion of individuals with two different alleles at a locus.
14. B – Inbreeding increases homozygosity and decreases genetic variation.
15. C – Mutations arise mainly due to errors in DNA replication or external factors.
16. E – Random mating does not change allele frequencies; it maintains equilibrium.
17. B – Allele fixation occurs when an allele reaches 100% frequency, replacing others.
18. B – ppp and qqq represent the frequencies of two alleles at a locus; their sum equals 1.
19. B – Small isolated populations lose genetic variation over time due to drift and inbreeding.
20. B – Large populations buffer against random fluctuations in allele frequencies caused by genetic drift.
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