Top 50 MCQ on Mendelian genetics
1. In incomplete dominance, the phenotype of the heterozygous individual is:
a) An intermediate blend of the two parental phenotypes
b) One of the two parental phenotypes
c) A completely new phenotype
d) Not expressed
Answer: a) An intermediate blend of the two parental phenotypes
2. Codominance occurs when:
a) Two alleles are both fully expressed in the heterozygous individual
b) One allele completely masks the expression of the other allele
c) One allele is partially expressed in the heterozygous individual
d) None of the above
Answer: a) Two alleles are both fully expressed in the heterozygous individual
3. ABO blood groups in humans are an example of:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Polygenic inheritance
Answer: c) Multiple allelism
4. Multiple allelism refers to the existence of:
a) Multiple alleles at a single gene locus
b) Multiple gene loci controlling a single trait
c) Multiple gene interactions influencing a trait
d) Multiple generations involved in inheritance
Answer: a) Multiple alleles at a single gene locus
5. Polygenic inheritance occurs when:
a) Multiple genes interact to influence a single trait
b) A single gene has multiple alleles
c) Gene expression is influenced by the environment
d) The phenotype is determined by a single gene
Answer: a) Multiple genes interact to influence a single trait
6. Pleiotropy refers to:
a) The interaction of multiple genes in determining a single trait
b) The expression of multiple phenotypes from a single gene
c) The presence of multiple alleles at a gene locus
d) The influence of the environment on gene expression
Answer: b) The expression of multiple phenotypes from a single gene
7. Gene interaction occurs when:
a) Multiple genes interact to influence a single trait
b) A single gene has multiple alleles
c) Gene expression is influenced by the environment
d) The phenotype is determined by a single gene
Answer: a) Multiple genes interact to influence a single trait
8. The phenotype of a heterozygote in codominance is:
a) An intermediate blend of the two parental phenotypes
b) One of the two parental phenotypes
c) A completely new phenotype
d) Not expressed
Answer: c) A completely new phenotype
9. Incomplete dominance is best exemplified by the inheritance of:
a) ABO blood groups in humans
b) Eye color in fruit flies
c) Seed color in pea plants
d) Fur color in rabbits
Answer: c) Seed color in pea plants
10. When a trait is influenced by multiple genes, it is called:
a) Codominance
b) Multiple allelism
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
11. The phenomenon where a single gene has multiple effects on the phenotype is known as:
a) Incomplete dominance
b) Codominance
c) Pleiotropy
d) Gene interaction
Answer: c) Pleiotropy
12. The ABO blood group system in humans is an example of:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Polygenic inheritance
Answer: c) Multiple allelism
13. In polygenic inheritance, the phenotypic traits:
a) Are controlled by a single gene
b) Follow Mendelian inheritance patterns
c) Show a continuous range of variation
d) Are influenced by environmental factors only
Answer: c) Show a continuous range of variation
14. In a cross between two plants with incomplete dominance, if the homozygous dominant genotype is RR and the homozygous recessive genotype is rr, what will be the phenotype of the heterozygous offspring?
a) Red
b) White
c) Pink
d) Not expressed
Answer: c) Pink
15. In codominance, if a black chicken (BB) is crossed with a white chicken (WW), what will be the phenotype of the offspring?
a) Black
b) White
c) Gray
d) Speckled
Answer: d) Speckled
16. Which of the following is an example of multiple allelism?
a) Eye color in humans
b) Height in pea plants
c) ABO blood groups in humans
d) Fur color in mice
Answer: c) ABO blood groups in humans
17. In pleiotropy, a single gene can affect:
a) Multiple traits
b) Multiple alleles
c) Multiple generations
d) Multiple genes
Answer: a) Multiple traits
18. The skin color in humans is an example of:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
19. The interaction between genes at different loci is known as:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Gene interaction
Answer: d) Gene interaction
20. Which of the following terms describes the relationship between alleles in codominance?
a) Dominant-recessive
b) Partial dominance
c) Equal expression
d) None of the above
Answer: c) Equal expression
21. In incomplete dominance, the phenotype of the heterozygous individual is:
a) An intermediate blend of the two parental phenotypes
b) One of the two parental phenotypes
c) A completely new phenotype
d) Not expressed
Answer: a) An intermediate blend of the two parental phenotypes
22. Codominance occurs when:
a) Two alleles are both fully expressed in the heterozygous individual
b) One allele completely masks the expression of the other allele
c) One allele is partially expressed in the heterozygous individual
d) None of the above
Answer: a) Two alleles are both fully expressed in the heterozygous individual
23. ABO blood groups in humans are an example of:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Polygenic inheritance
Answer: b) Codominance
24. Multiple allelism refers to the existence of:
a) Multiple alleles at a single gene locus
b) Multiple gene loci controlling a single trait
c) Multiple gene interactions influencing a trait
d) Multiple generations involved in inheritance
Answer: a) Multiple alleles at a single gene locus
25. Polygenic inheritance occurs when:
a) Multiple genes interact to influence a single trait
b) A single gene has multiple alleles
c) Gene expression is influenced by the environment
d) The phenotype is determined by a single gene
Answer: a) Multiple genes interact to influence a single trait
26. Pleiotropy refers to:
a) The interaction of multiple genes in determining a single trait
b) The expression of multiple phenotypes from a single gene
c) The presence of multiple alleles at a gene locus
d) The influence of the environment on gene expression
Answer: b) The expression of multiple phenotypes from a single gene
27. Gene interaction occurs when:
a) Multiple genes interact to influence a single trait
b) A single gene has multiple alleles
c) Gene expression is influenced by the environment
d) The phenotype is determined by a single gene
Answer: a) Multiple genes interact to influence a single trait
28. The phenotype of a heterozygote in codominance is:
a) An intermediate blend of the two parental phenotypes
b) One of the two parental phenotypes
c) A completely new phenotype
d) Not expressed
Answer: c) A completely new phenotype
29. Incomplete dominance is best exemplified by the inheritance of:
a) ABO blood groups in humans
b) Eye color in fruit flies
c) Seed color in pea plants
d) Fur color in rabbits
Answer: c) Seed color in pea plants
30. When a trait is influenced by multiple genes, it is called:
a) Codominance
b) Multiple allelism
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
31. The phenomenon where a single gene has multiple effects on the phenotype is known as:
a) Incomplete dominance
b) Codominance
c) Pleiotropy
d) Gene interaction
Answer: c) Pleiotropy
32. The ABO blood group system in humans is an example of:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Polygenic inheritance
Answer: b) Codominance
33.Which of the following describes the inheritance pattern of human height?
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
34. The interaction between genes at different loci is known as:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Gene interaction
Answer: d) Gene interaction
35. In incomplete dominance, if a red-flowered plant (RR) is crossed with a white-flowered plant (WW), what will be the phenotype of the offspring?
a) Red
b) White
c) Pink
d) Not expressed
Answer: c) Pink
36. In codominance, if a black chicken (BB) is crossed with a white chicken (WW), what will be the phenotype of the offspring?
a) Black
b) White
c) Gray
d) Speckled
Answer: d) Speckled
37. Which of the following is an example of multiple allelism?
a) Eye color in humans
b) Height in pea plants
c) ABO blood groups in humans
d) Fur color in mice
Answer: c) ABO blood groups in humans
38. In pleiotropy, a single gene can affect:
a) Multiple traits
b) Multiple alleles
c) Multiple generations
d) Multiple genes
Answer: a) Multiple traits
39. The skin color in humans is an example of:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
40. The interaction between multiple genes to determine the color of a flower is an example of:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
41. In incomplete dominance, the ratio of phenotypes in the F2 generation of a monohybrid cross is:
a) 3:1
b) 1:2:1
c) 1:1
d) 9:3:3:1
Answer: b) 1:2:1
42. The ABO blood groups are determined by:
a) Multiple alleles and codominance
b) Multiple alleles and incomplete dominance
c) Multiple alleles and pleiotropy
d) Multiple alleles and polygenic inheritance
Answer: a) Multiple alleles and codominance
43. The expression of a gene for eye color can be influenced by the environment. This is an example of:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Gene-environment interaction
Answer: d) Gene-environment interaction
44. In the inheritance of human blood type, the IA and IB alleles are:
a) Codominant
b) Incompletely dominant
c) Recessive
d) Pleiotropic
Answer: a) Codominant
45. The inheritance of skin color in humans is an example of:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
46. If two alleles at a gene locus show incomplete dominance, what will be the phenotype of the heterozygous individual?
a
) An intermediate blend of the two parental phenotypes
b) One of the two parental phenotypes
c) A completely new phenotype
d) Not expressed
Answer: a) An intermediate blend of the two parental phenotypes
47. In codominance, the phenotypic ratio of a monohybrid cross would be:
a) 3:1
b) 1:2:1
c) 1:1
d) 9:3:3:1
Answer: b) 1:2:1
48. The presence of multiple alleles at a single gene locus is known as:
a) Incomplete dominance
b) Codominance
c) Multiple allelism
d) Polygenic inheritance
Answer: c) Multiple allelism
49. The phenomenon where a single gene has multiple effects on the phenotype is known as:
a) Incomplete dominance
b) Codominance
c) Pleiotropy
d) Polygenic inheritance
Answer: c) Pleiotropy
50. The interaction of multiple genes in determining a single trait is called:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Pleiotropy
Answer: c) Polygenic inheritance
Please note that these answers are based on general knowledge, and there may be specific variations or exceptions in certain cases.
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