MCQs on Biometrical / Quantitative Genetics For ARS NET / SRF Exams

1. In biometrical genetics, the term “penetrance” describes the:
   A) Variability of phenotype expression
   B) Degree to which a gene is expressed
   C) Frequency of phenotype among carriers
   D) Difference between genotype and phenotype
   Answer: C

2. “Expressivity” refers to:
   A) Whether a gene is dominant or recessive
   B) The degree to which a gene is expressed phenotypically
   C) Number of genes controlling a trait
   D) Frequency of recombination
   Answer: B

3. A change in gene expression without changes to the DNA sequence is known as:
   A) Mutation
   B) Epigenetic change
   C) Expressivity
   D) Recessive lethal
   Answer: B

4. A recessive lethal allele causes:
   A) Death in heterozygotes
   B) Reduced fitness in heterozygotes
   C) Death in homozygotes
   D) Increased mutation rate
   Answer: C

5. A trait influenced by multiple genes is described as:
   A) Monogenic
   B) Polygenic
   C) Epistatic
   D) Lethal
   Answer: B

6. The multiple‑factor hypothesis refers to:
   A) Mendelian dominance
   B) Multiple genes contributing to variation
   C) Epistatic suppression
   D) Chromosomal linkage
   Answer: B

7. Biometrical genetics primarily studies:
   A) Single‑gene inheritance
   B) Quantitative traits and their genetic determinants
   C) Classical Mendelian crosses
   D) Mutation rates
   Answer: B

8. The scientist who pioneered tools for biometrical analysis:
   A) Mendel
   B) R. A. Fisher
   C) Pearson
   D) Jinks
   Answer: B

9. Karl Pearson’s contributions include all EXCEPT:
   A) Chi‑squared test
   B) Regression coefficients
   C) Mutation of gametes
   D) Standard deviation
   Answer: C

10. Pearson’s Law of Ancestral Heredity indicated heredity from:
    A) Only parents
    B) Parents and more distant ancestors
    C) Environmental factors only
    D) Random mutation
    Answer: B

11. D² statistic, used to assess genetic divergence, was developed by:
    A) Fisher
    B) Mahalanobis
    C) Jinks
    D) Kempthorne
    Answer: B

12. Variability in traits can be measured using:
    A) Range, variance, coefficient of variation
    B) Mutation rate only
    C) Blood groups
    D) Epigenetic markers
    Answer: A

13. Diallel, partial diallel, and line × tester are examples of:
    A) Genetic markers
    B) Breeding designs for parental evaluation
    C) Statistical tests
    D) Mendelian crosses
    Answer: B

14. Triple test cross helps detect:
    A) Simple dominance
    B) Epistasis and estimates of additive/dominance variance
    C) Mutation rate
    D) Blood group inheritance
    Answer: B

15. Generation mean analysis typically includes which generations?
    A) P1, P2, F1 only
    B) F2 and backcrosses only
    C) P1, P2, F1, F2, B1, B2
    D) Only F3
    Answer: C

16. The Hayman five‑parameter model excludes which generation?
    A) B1 & B2
    B) P1 & P2
    C) F3 in place of backcrosses
    D) F2
    Answer: C

17. Partial diallel crossing allows evaluation of:
    A) All possible crosses among parents
    B) Only some crosses among parents
    C) Mutation rates
    D) Single‑parent reproduction
    Answer: B

18. The advantage of triple test cross includes:
    A) Simple calculations
    B) Detection of non‑additive gene interactions
    C) Minimal cross generation
    D) Lower cost
    Answer: B

19. Advantages of D² statistics include:
    A) Identification of elite genotypes via clustering
    B) Mutation detection
    C) Single gene analysis
    D) No significance testing
    Answer: A

20. In biometrical genetics, “stability analysis” helps assess:
    A) Chromosomal stability only
    B) Adaptation and performance consistency across environments
    C) Mendelian inheritance
    D) Mutation rates
    Answer: B

21. What is “heritability”?
    A) A measure of phenotypic variance due to genetic variance
    B) Strength of gene expression
    C) Frequency of mutants
    D) Rate of recombination
    Answer: A

22. The North Carolina Design II (NCD II) involves:
    A) Random F2 males backcrossed to both parents
    B) Only F2 self‑pollination
    C) Triple test cross design
    D) Diallel crosses
    Answer: A

23. Genetic advance under selection is NOT dependent on:
    A) Phenotypic variability
    B) Genotypic variability
    C) Selection intensity
    D) Mutation rate
    Answer: D

24. Hardy–Weinberg law applies to:
    A) Quantitative traits only
    B) Allele frequencies under random mating
    C) Epistasis only
    D) Mendel’s ratios
    Answer: B

25. Who contributed to human behavior and biometrical genetics and supervised many future researchers?
    A) Karl Pearson
    B) John L. Jinks
    C) Gregor Mendel
    D) R. A. Fisher
    Answer: B

26. Marker systems like VNTR are used for:
    A) Measuring variability
    B) Forensics and identity testing
    C) Biometrical designs
    D) Diallel analysis
    Answer: B

27. Genetic markers such as HLA genes are used in:
    A) Selective breeding
    B) Organ transplantation compatibility
    C) D² statistic calculation
    D) Generation mean analysis
    Answer: B

28. RAPD markers are valuable for:
    A) Gene editing
    B) Studying genetic diversity in populations
    C) DNA replication studies
    D) Mendelian crosses
    Answer: B

29. In animal breeding, genetic markers aid:
    A) Increase lifespan
    B) Selective breeding efficiency
    C) Determine age
    D) Change phenotype taste
    Answer: B

30. SNPs and mtDNA markers help to study:
    A) Population evolution and diversity
    B) Protein synthesis
    C) Cytogenetics only
    D) Mendelian inheritance
    Answer: A

31. In generation mean analysis, non‑allelic interactions are also called:
    A) Dominance
    B) Epistasis
    C) Polygenic variance
    D) Penetrance
    Answer: B

32. The primary method for partitioning genetic variance into additive and dominance components is:
    A) Triple test cross
    B) Generation mean analysis
    C) Hardy–Weinberg principle
    D) Epigenetic analysis
    Answer: B

33. In a diallel cross, GCA and SCA stand for:
    A) General Combining Ability & Specific Combining Ability
    B) Genetic Coding Ability & Special Code Ability
    C) General Chromosomal Assessment & Specific Chromosomal Assessment
    D) None of the above
    Answer: A

34. What statistical test is foundational for goodness-of‑fit in biometrical genetics?
    A) t‑test
    B) Chi‑square test
    C) ANOVA only
    D) None of the above
    Answer: B

35. The term that describes genes influencing multiple traits is:
    A) Pleiotropy
    B) Polygenic inheritance
    C) Linkage
    D) Mutagenesis
    Answer: A

36. Genetic correlation measures covariance between traits, divided by:
    A) Total variance
    B) Genotypic variance only
    C) Product of square roots of variances
    D) Environmental variance
    Answer: C

37. Path coefficient analysis is used to:
    A) Measure direct and indirect causal effects among traits
    B) Map chromosomes
    C) Test linkage
    D) Estimate mutation rates
    Answer: A

38. The design including all possible crosses among n parents is called:
    A) Diallel cross
    B) NCD II
    C) D² statistic
    D) Triple test cross
    Answer: A

39. Epistatic interactions can inflate:
    A) Additive genetic variance only
    B) Phenotypic variance unpredictably
    C) Only environmental variance
    D) None of the above
    Answer: B

40. Biometrical genetics helps in breeding by aiding:
    A) Selection of elite genotypes
    B) Mutagenesis only
    C) Cloning techniques
    D) None of the above
    Answer: A

41. Fisher’s 1918 paper on human correlations emphasized:
    A) Biometrical analysis of inheritance
    B) Mendelian ratios only
    C) Generation mean analysis
    D) Triple test cross design
    Answer: A

42. In quantitative genetics, “selection differential” refers to:
    A) Difference between selected parents and population mean
    B) Mutation rate difference
    C) Allele frequency shift
    D) Epistasis magnitude
    Answer: A

43. Broad‑sense heritability includes:
    A) Only additive variance
    B) Additive, dominance, and genetic interactions
    C) Only environmental variance
    D) Epigenetic effects only
    Answer: B

44. Narrow‑sense heritability includes:
    A) Only dominance variance
    B) Only additive genetic variance
    C) Both additive and dominance
    D) Only environmental variance
    Answer: B

45. Stability in biometrical terms means:
    A) Same genotype performance in varied environments
    B) No mutation
    C) Consistent allele frequency
    D) Mendelian inheritance
    Answer: A

46. Path analysis partitions correlation into:
    A) Additive and dominance components
    B) Direct and indirect effects
    C) Environmental only
    D) None of the above
    Answer: B

47. Generation mean analysis can estimate:
    A) Only additive variance
    B) Additive, dominance, and epistatic effects
    C) Selection intensity only
    D) Heritability only
    Answer: B

48. Heritability estimate along with selection intensity can predict:
    A) Mutation rate
    B) Genetic advance
    C) Epistasis
    D) D² value
    Answer: B

49. Biometrical genetics often uses:
    A) Single‑gene models only
    B) Statistical measures like variance and regression
    C) Cloning techniques
    D) All of the above
    Answer: B

50. The concept of combining ability (GCA/SCA) is most useful in:
    A) Mutation detection
    B) Hybrid breeding programs
    C) Epigenetic studies
    D) Single‑gene mapping
    Answer: B

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