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3.3 Genetic Drift & Effective Population Size โ Test 3
Q1. A random change in allele frequencies from one generation to the next, especially in small populations, is called:โ Genetic drift
Q2. Genetic drift occurs primarily by:โ Chance (random sampling)
Q3. The abrupt change in allele frequencies that occurs when a few individuals found a new population is called the:โ Founder effect
Q4. When a disaster drastically reduces a population's size, so that the survivors are unlikely to represent the original gene pool, the phenomenon is called the:โ Bottleneck effect
Q5. An earthquake on an island leaves only a few surviving lizards, which then repopulate the island. The resulting loss of genetic variation illustrates the:โ Bottleneck effect
Q6. The northern elephant seal was reduced to about 20 individuals in the 1890s and now shows very little protein variation. This lack of variation is due to:โ A population bottleneck and genetic drift
Q7. Which factor is LEAST responsible for genetic drift?โ Limited resources
Q8. Which statement about genetic drift is NOT correct?โ It reliably eliminates harmful alleles
Q9. Twenty small populations are polymorphic for a locus (T, t). After many generations, most became fixed for one allele. This best illustrates that genetic drift:โ Is more likely in small populations
Q10. The effective population size (Ne) for a population with 40 breeding males and 10 breeding females is approximately:โ 32
Q11. In a population of 240 with 200 breeding females and 40 polygamous breeding males, the approximate effective population size (Ne) is:โ 133
Q12. A population has 150 breeding females and 50 breeding males. Its effective population size (Ne) is:โ 150
Q13. The inbreeding coefficient (F) of the offspring of a mating between full-sib siblings (brother and sister) is:โ 0.25
Q14. With allele frequencies p = 0.3 and q = 0.7, the expected heterozygosity is 0.42, but the observed is 0.28 after inbreeding. The inbreeding coefficient (F) is:โ 0.33
Q15. A founder population is entirely Aa. After three generations of self-fertilisation, the genotype frequencies of AA : Aa : aa are:โ 7/16 : 1/8 : 7/16
Q16. If the level of heterozygosity in generation 0 is 1, the remaining heterozygosity after three generations of selfing is:โ 0.125
Q17. At an autosomal locus, A1 = 0.6 and A2 = 0.4, with mutation rates A1โA2 (ฮผ = 1ร10โปโต) and A2โA1 (u = 2ร10โปโต). The equilibrium frequency of A1 is:โ 0.67
Q18. A small but persistent frequency of lethal recessive alleles tends to remain in a population because of:โ Mutation-selection balance
Q19. Which statement is NOT correct regarding genetic drift?โ It generates new genetic variation
Q20. Match each population-genetics concept with its description and select the correct option.โ A-ii, B-iv, C-i, D-iii