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Question 1. Which equation represents the Hardy‑Weinberg equilibrium for a bi‑allelic locus? A) p + q = 1 B) p² + 2pq + q² = 1 C) p² + q² = 1 D) 2p + 2q = 1 Answer: B Explanation: The genotype frequencies under Hardy‑Weinberg are p² (AA), 2pq (Aa), and q² (aa), summing to 1. Question 2. In a population where selection favors allele A, which force is primarily responsible for the change in allele frequency? A) Genetic drift B) Migration C) Mutation D) Selection Answer: D Explanation: Selection directly increases the frequency of the advantageous allele. Question 3. The phenotypic variance (V_P) can be partitioned into which two main components? A) Additive and dominance variance B) Genetic and environmental variance C) Maternal and paternal variance D) Within‑family and between‑family variance Answer: B
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Explanation: V_P = V_G (genetic) + V_E (environmental). Question 4. Narrow‑sense heritability (h²) is the ratio of which variances? A) V_G / V_P B) V_A / V_P C) V_D / V_P D) V_E / V_P Answer: B Explanation: h² = additive genetic variance (V_A) divided by phenotypic variance. Question 5. Which statement best describes repeatability? A) Correlation between two different traits B) Consistency of repeated measurements on the same individual C) Ratio of V_A to V_G D) Heritability of a binary trait Answer: B Explanation: Repeatability measures the proportion of total variance that is due to permanent differences among individuals. Question 6. Genetic correlation between two traits reflects: A) Environmental similarity only B) Shared additive genetic effects C) Phenotypic similarity only D) Random sampling error Answer: B
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Answer: B Explanation: Longer L reduces the rate of genetic progress per unit time. Question 10. Which selection method uses information from both the animal itself and its relatives? A) Mass selection B) Within‑family selection C) Family selection D) Independent culling Answer: C Explanation: Family selection incorporates data from the whole family (parents, progeny, sibs). Question 11. Correlated response in trait Y when selecting on trait X depends on: A) Genetic correlation between X and Y, and heritability of X B) Phenotypic correlation only C) Selection intensity on Y D) Environmental variance of Y Answer: A Explanation: The correlated response formula includes r_G (genetic correlation) and h²_X. Question 12. In economic modeling, the partial economic value (PEV) of a trait represents: A) Its market price B) The change in profit per unit change in the trait, holding other traits constant C) The total cost of measuring the trait D) The heritability of the trait
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Answer: B Explanation: PEV quantifies the contribution of a one‑unit change to overall profit. Question 13. A selection index (I) is constructed to: A) Maximize phenotypic variance B) Minimize inbreeding C) Maximize correlation with the breeding objective (H) D) Equalize all trait weights Answer: C Explanation: Index weights are chosen so that I is most predictive of H. Question 14. The accuracy of a selection index (r_IH) is most directly influenced by: A) Number of traits in the index B) Accuracy of individual EBVs and economic weights C) Generation interval D) Mutation rate Answer: B Explanation: Higher EBV accuracy and appropriate weighting raise r_IH. Question 15. Tandem selection differs from index selection because: A) It selects on one trait at a time, rotating among traits B) It uses genomic information C) It requires no economic weights D) It only applies to dairy cattle Answer: A
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Explanation: Standardization ensures that differences reflect genetics, not recording style. Question 19. Pedigree completeness is crucial for: A) Estimating environmental effects B) Calculating inbreeding coefficients accurately C) Determining feed conversion ratios D) Setting market prices Answer: B Explanation: Accurate pedigrees are needed to trace shared ancestry and compute F. Question 20. DNA parentage verification primarily reduces: A) Genetic gain B) Phenotypic variance C) Misidentification errors in the pedigree D) Generation interval Answer: C Explanation: Genotyping confirms true sire/dam, correcting pedigree mistakes. Question 21. Which fixed effect is most likely to influence milk yield in dairy cows? A) Sire genotype B) Season of calving C) Marker genotype D) Mutation rate Answer: B Explanation: Seasonal effects (temperature, feed) are non‑genetic influences on yield.
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Question 22. The mixed linear model y = Xβ + Zu + e includes Z, which links: A) Fixed effects to observations B) Random animal effects to observations C) Environmental covariates to residuals D) Genetic markers to phenotypes Answer: B Explanation: Z is the incidence matrix for random animal (genetic) effects. Question 23. In BLUP, the term “Best” refers to: A) Highest possible heritability B) Minimum mean squared error among linear unbiased estimators C) Maximum likelihood estimates D) Most computationally efficient algorithm Answer: B Explanation: BLUP provides the estimator with smallest prediction error variance. Question 24. The additive relationship matrix (A‑matrix) contains: A) Covariances between environmental effects B) Expected proportion of genes shared identical by descent between any two animals C) Phenotypic correlations among traits D) Marker allele frequencies Answer: B Explanation: A‑matrix quantifies genetic relationships based on pedigree.
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A) Consist only of elite sires B) Have both genotypes and high‑quality phenotypes C) Be unrelated to the selection candidates D) Contain only male animals Answer: B Explanation: Accurate genomic predictions need a well‑phenotyped, genotyped reference set. Question 29. Single‑Step GBLUP (ssGBLUP) differs from traditional GBLUP because: A) It uses only pedigree information B) It combines pedigree and genomic relationships in a single matrix C) It ignores marker effects D) It requires no phenotypic data Answer: B Explanation: ssGBLUP merges A‑matrix and G‑matrix to evaluate all animals together. Question 30. Reducing the generation interval (L) most directly impacts: A) Heritability B) Genetic standard deviation (σ_A) C) Rate of genetic gain per year D) Mutation rate Answer: C Explanation: Shorter L increases the number of cycles per unit time, boosting annual gain. Question 31. In a nucleus‑multiplier breeding scheme, the nucleus: A) Supplies a small, highly selected group of animals that generate genetic progress
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B) Receives animals from commercial herds C) Has the highest inbreeding rate D) Is unrelated to the multiplier herds Answer: A Explanation: The nucleus is the core of intensive selection; multipliers disseminate its genetics. Question 32. Positive assortative mating (like with like) tends to: A) Decrease additive genetic variance B) Increase additive genetic variance for the selected trait C) Eliminate inbreeding D) Reduce genetic gain Answer: B Explanation: Mating similar high‑merit animals amplifies variance for that trait. Question 33. Optimal contribution selection (OCS) primarily aims to: A) Maximize genetic gain while controlling the rate of inbreeding B) Minimize generation interval C) Increase mutation frequency D) Equalize the number of offspring per sire Answer: A Explanation: OCS allocates mating contributions to balance gain and ΔF. Question 34. Artificial insemination (AI) contributes to higher selection intensity because: A) It reduces the need for phenotypic records B) A single elite sire can inseminate many females
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D) Increase the generation interval Answer: B Explanation: Modeling fixed effects captures systematic environmental changes. Question 38. A cost‑benefit analysis of a breeding programme should include: A) Only the cost of feed B) Genotyping, data collection, and the monetary value of genetic gain C) The price of farm equipment only D) None of the above Answer: B Explanation: ROI compares all programme expenses against the profit from genetic improvement. Question 39. Robustness of a breeding programme refers to its: A) Ability to generate the highest possible genetic gain regardless of market changes B) Capacity to maintain performance despite fluctuations in prices, disease, or consumer preferences C) Speed of data entry D) Number of traits recorded Answer: B Explanation: A robust programme can adapt to external uncertainties while staying effective. Question 40. Including welfare traits (e.g., disease resistance) in the breeding objective helps: A) Reduce genetic diversity B) Increase the generation interval
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C) Align genetic improvement with societal expectations D) Decrease accuracy of EBVs Answer: C Explanation: Welfare traits add value by meeting ethical and market demands. Question 41. Managing genetic diversity while pursuing gain is primarily achieved by: A) Selecting only the top 1 % of animals B) Monitoring and limiting the rate of inbreeding (ΔF) C) Ignoring pedigree information D) Using only male selection Answer: B Explanation: Controlling ΔF preserves variation and avoids deleterious effects. Question 42. The economic discount rate is used in breeding programmes to: A) Inflate future profits to present value B) Convert future genetic gains into present‑day monetary terms C) Increase heritability estimates D) Reduce mutation effects Answer: B Explanation: Discounting accounts for the time value of money when evaluating long‑term gains. Question 43. Which of the following is a non‑additive genetic effect? A) Additive variance B) Dominance variance
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Question 46. The term “generation interval” (L) is defined as: A) Age of the dam at first calving B) Average age of parents when they produce offspring that enter the breeding pool C) Time between birth and first record D) Number of generations per decade Answer: B Explanation: L measures the average age of selection candidates’ parents at reproduction. Question 47. Which of the following strategies directly reduces the generation interval? A) Using older sires for breeding B) Implementing AI and early‑life selection C) Increasing the number of recorded traits D) Raising the mutation rate Answer: B Explanation: Early identification of superior animals and AI allow younger animals to reproduce. Question 48. In a closed nucleus breeding scheme, genetic gain is limited primarily by: A) Lack of external genetic input B) High mutation rates C) Excessive use of AI D) Over‑reliance on genomic selection Answer: A Explanation: Without new alleles from outside, progress depends solely on existing variation. Question 49. The term “selection intensity” (i) increases when:
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A) A larger proportion of the population is selected B) A smaller proportion of the population is selected C) Heritability decreases D) Generation interval increases Answer: B Explanation: Selecting a smaller fraction raises i, reflecting stricter selection. Question 50. Which of the following best describes the purpose of independent culling levels? A) To assign economic weights to traits B) To set minimum acceptable standards for each trait, discarding animals that fail any level C) To maximize genetic correlation between traits D) To calculate heritability Answer: B Explanation: Independent culling applies thresholds; an animal must meet all to be retained. Question 51. The additive genetic standard deviation (σ_A) is derived from: A) Square root of additive variance (V_A) B) Square root of phenotypic variance (V_P) C) Square root of environmental variance (V_E) D) Square root of dominance variance (V_D) Answer: A Explanation: σ_A = √V_A, representing spread of additive genetic values. Question 52. A high repeatability (r) for a trait indicates:
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Question 55. The main advantage of using genomic selection for traits expressed late in life (e.g., carcass quality) is: A) It eliminates the need for phenotypic records entirely B) It allows early‑life prediction of breeding values, increasing accuracy and reducing L C) It reduces the cost of genotyping to zero D) It increases mutation rates Answer: B Explanation: Genomic information can predict values before phenotypes are observable. Question 56. A high genetic gain per year is most likely achieved by: A) Low selection intensity, high heritability, long generation interval B) High selection intensity, high accuracy, short generation interval C) Low accuracy, low heritability, long generation interval D) High mutation rate, low selection intensity Answer: B Explanation: ΔG per year = (i · r · σ_A) / L; maximizing i, r, σ_A and minimizing L gives the greatest gain. Question 57. Which of the following best describes “genetic merit” of an animal? A) Its phenotypic performance only B) The weighted sum of its EBVs for all traits in the breeding objective C) The number of offspring it produces D) Its inbreeding coefficient Answer: B Explanation: Genetic merit combines EBVs with economic weights to reflect overall value.
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Question 58. A mutation that introduces a new advantageous allele will affect allele frequency: A) Immediately to fixation B) Gradually, depending on selection pressure and drift C) Not at all, because mutation rates are negligible D) Only in the next generation Answer: B Explanation: The new allele spreads according to selection intensity, genetic drift, and population size. Question 59. In the context of breeding programmes, “economic weights” refer to: A) The cost of genotyping each animal B) The relative contribution of each trait to the overall profit (partial economic values) C) The market price of the animal’s meat D) The heritability of each trait Answer: B Explanation: Economic weights translate trait changes into monetary terms for the index. Question 60. Which of the following is a direct consequence of high inbreeding (ΔF) in a breeding population? A) Increased additive genetic variance B) Inbreeding depression, reducing fitness traits C) Higher mutation rates D) Lower generation interval Answer: B
