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3.3 Population Genetics — Test 1
Q1. The maintenance of the sickle-cell allele at appreciable frequency in malarial regions of Central Africa is best explained by:✓ Heterozygote advantage
Q2. In a sickle-cell context, the genotype 'AS' (carrier) surviving better than both homozygotes illustrates:✓ Heterozygote advantage
Q3. Random changes in allele frequency from one generation to the next, due purely to chance sampling, are called:✓ Genetic drift
Q4. Genetic drift has the strongest effect in:✓ Small populations
Q5. Which statement about genetic drift is FALSE?✓ Drift increases genetic variation within a population
Q6. The Sewall Wright effect refers to:✓ Genetic drift following a sharp decline in population size
Q7. The drastic reduction of the northern elephant seal to about 20 individuals, followed by low genetic variation, is best explained by:✓ Population bottleneck and genetic drift
Q8. When a few individuals colonise a new area and their descendants carry only a non-representative sample of the original gene pool, this is the:✓ Founder effect
Q9. The effect of natural selection on allele frequencies may be counteracted by:✓ Gene flow (migration)
Q10. Which process increases genetic variation within a population?✓ Immigration (gene flow into the population)
Q11. Which factor does NOT contribute to microevolutionary change (change in allele frequencies)?✓ Random mating in an infinite population
Q12. Which is NOT an assumption of the Hardy–Weinberg equilibrium model?✓ One allele must be dominant over the other
Q13. Which condition is required for a population to remain in Hardy–Weinberg equilibrium?✓ Random mating
Q14. Which of the following would make the Hardy–Weinberg principle inaccurate for a population?✓ Natural selection is acting on the locus
3.3 Population Genetics — Test 2
Q15. The Hardy–Weinberg principle is used chiefly to:✓ Test whether a population is evolving at a locus
Q16. If red hair is a recessive trait and the recessive allele frequency (q) is 0.3 in a Hardy–Weinberg population, the percentage of carriers (heterozygotes) is:✓ 42%
Q17. A group of potentially interbreeding individuals of the same species occupying the same area is called a:✓ Population
Q18. A randomly (panmictically) mating population is the kind that best fits the assumptions of:✓ Hardy–Weinberg equilibrium
Q19. According to neo-Darwinism, natural selection operates through:✓ Differential reproduction of genotypes
Q20. A bacterial population developing pesticide/antibiotic resistance, with the resistant allele rising within a few generations, is an example of:✓ Microevolution
Q21. If the rate of non-synonymous substitutions exceeds the rate of synonymous substitutions in a gene, it indicates that:✓ Positive (Darwinian) selection is acting on the protein
Q22. A population in which the frequency of an autosomal recessive disorder (phenylketonuria) matches the q² predicted from allele frequencies can be said to be:✓ In Hardy–Weinberg equilibrium at that locus
Q23. Purifying (negative) selection is the form of selection that:✓ Removes deleterious alleles, conserving the existing sequence
Q24. In the Hardy–Weinberg equation p² + 2pq + q² = 1, the term 2pq represents the frequency of:✓ Heterozygous individuals
Q25. If the frequency of a recessive autosomal disorder is 1 in 10,000 (q² = 0.0001) in a Hardy–Weinberg population, the carrier frequency (2pq) is about:✓ About 2% (1 in 50)
Q26. Gene flow between two populations tends to:✓ Make the populations more genetically similar
Q27. Inbreeding in a population primarily increases the frequency of:✓ Homozygous genotypes
Q28. Mutation is important in evolution mainly because it:✓ Is the ultimate source of new genetic variation