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6.4 Heritability & Quantitative Genetics — Test 1
Q1. Broad-sense heritability (H²) of a trait is calculated as:✓ V_G / (V_G + V_E)
Q2. Two inbred bean lines are crossed; the F1 variance is 2.0 and the F2 variance is 7.0. The broad-sense heritability of bean length in F2 is approximately:✓ 0.71
Q3. Narrow-sense heritability (h²) is correctly represented by (V_A additive, V_D dominance, V_T total phenotypic):✓ V_A / V_T
Q4. Which statement about heritability of a quantitative character is TRUE?✓ It measures the proportion of phenotypic variation due to genetic factors
Q5. Heritability estimates the proportion of:✓ Phenotypic variation in a group (population) attributable to genes
Q6. If the environmental variance (V_E) increases while all other components stay the same:✓ Broad-sense heritability decreases
Q7. Higher heritability for a trait in a population is more likely when:✓ The environment is uniform
Q8. In Drosophila with mean body length 2 mm, flies of 3 mm are selected and interbred; their progeny average 2.5 mm. The realised heritability is:✓ 0.50
Q9. The breeder's equation predicting the response to selection is:✓ R = h² × S
Q10. The total phenotypic variance (V_P) of a quantitative trait equals:✓ V_G + V_E
Q11. The component of genetic variance that responds predictably to selection is the:✓ Additive variance (V_A)
Q12. The inbreeding coefficient (F) of an individual is the probability that:✓ Two alleles at a locus are identical by descent
Q13. Inbreeding depression is mainly caused by:✓ Increased homozygosity for deleterious recessive alleles
Q14. Hybrid vigour (heterosis) refers to:✓ Superior performance of hybrids over their inbred parents
Q15. The effect of outcrossing (outbreeding) in a population is to produce:✓ More heterozygotes than Hardy-Weinberg predicts
Q16. Continuous (quantitative) traits such as height typically show a ___ distribution in a population:✓ Normal (bell-shaped)
Q17. Which statement is INCORRECT?✓ Genetic erosion is a reduction in the level of homozygosity
Q18. Transgressive segregation refers to offspring that:✓ Show phenotypes beyond the range of both parents
Q19. The narrow-sense heritability is generally ___ the broad-sense heritability:✓ Less than or equal to
Q20. Match each quantitative-genetics term with its definition and select the correct option.✓ A-iii, B-i, C-ii, D-iv