1. What are polygenic traits?
a) Traits controlled by a single gene
b) Traits controlled by multiple genes
c) Traits influenced by environmental factors only
d) Traits with no genetic basis
Answer: b) Traits controlled by multiple genes
2. Which of the following is an example of a polygenic trait?
a) Blood type
b) Height
c) Cystic fibrosis
d) Hemophilia
Answer: b) Height
3. In quantitative inheritance, how are traits inherited?
a) By dominant and recessive alleles
b) By the interaction of several genes
c) By X-linked inheritance
d) By mutations only
Answer: b) By the interaction of several genes
4. Polygenic traits often show which type of inheritance pattern?
a) Discontinuous variation
b) Continuous variation
c) Co-dominance
d) Epistasis
Answer: b) Continuous variation
5. Which of the following best describes a trait governed by polygenic inheritance?
a) One gene affects one trait
b) One gene can produce multiple effects
c) Several genes contribute to one trait
d) Only environmental factors control the trait
Answer: c) Several genes contribute to one trait
6. What is the term for the genetic contribution to polygenic traits?
a) Genetic diversity
b) Genotypic ratio
c) Additive effect
d) Genetic drift
Answer: c) Additive effect
7. Which of the following is a characteristic of polygenic traits?
a) They show a discrete distribution.
b) They follow Mendelian inheritance patterns.
c) They are influenced by environmental factors.
d) They result from the interaction of two alleles.
Answer: c) They are influenced by environmental factors.
8. Which of the following is an example of a polygenic trait in humans?
a) Skin color
b) Eye color
c) Blood type
d) Ear lobe shape
Answer: a) Skin color
9. Which of these is true for polygenic inheritance?
a) It involves a single dominant allele.
b) The traits exhibit a wide range of phenotypes.
c) The trait is typically inherited in a Mendelian fashion.
d) Environmental factors do not affect polygenic traits.
Answer: b) The traits exhibit a wide range of phenotypes.
10. The combined effect of multiple genes on a single trait is called:
a) Epistasis
b) Pleiotropy
c) Polygenic inheritance
d) Codominance
Answer: c) Polygenic inheritance
11. What is the expected phenotypic distribution for a polygenic trait?
a) A bell-shaped curve
b) Two distinct categories
c) One extreme phenotype
d) A single dominant phenotype
Answer: a) A bell-shaped curve
12. Which of the following is NOT a polygenic trait?
a) Eye color
b) Skin color
c) Blood type
d) Height
Answer: c) Blood type
13. In polygenic inheritance, the number of genes involved:
a) Is always two
b) Can vary from one to many
c) Is always large and fixed
d) Depends only on environmental factors
Answer: b) Can vary from one to many
14. The term “quantitative inheritance” refers to:
a) Traits that are determined by the interaction of a few genes
b) Traits controlled by a single gene
c) Traits that exhibit continuous variation
d) Traits that are inherited through sex chromosomes
Answer: c) Traits that exhibit continuous variation
15. Which of the following traits is typically polygenic?
a) Human height
b) Cystic fibrosis
c) Colorblindness
d) Hemophilia
Answer: a) Human height
16. How are polygenic traits typically measured?
a) In discrete categories
b) By observing patterns of dominance and recessiveness
c) By their phenotypic range and distribution
d) By using Mendelian ratios
Answer: c) By their phenotypic range and distribution
17. Which of the following factors is NOT involved in the expression of polygenic traits?
a) The number of contributing genes
b) The interaction between alleles
c) Environmental influences
d) Dominance of alleles
Answer: d) Dominance of alleles
18. Which of these is an important characteristic of quantitative inheritance?
a) It shows discrete phenotypic classes.
b) It typically involves one gene.
c) It results in a broad phenotypic range.
d) It only involves genetic factors, not environmental factors.
Answer: c) It results in a broad phenotypic range.
19. How do environmental factors influence polygenic traits?
a) They do not affect polygenic traits.
b) They can modify the expression of the traits.
c) They solely determine the phenotype.
d) They eliminate polygenic traits.
Answer: b) They can modify the expression of the traits.
20. The expression of skin color in humans is an example of:
a) A monogenic trait
b) A polygenic trait
c) A Mendelian trait
d) A trait controlled by a single gene
Answer: b) A polygenic trait
21. Which of the following contributes to the variation seen in polygenic traits?
a) The number of alleles involved
b) Genetic mutations
c) The additive effects of multiple genes
d) The dominance relationships between alleles
Answer: c) The additive effects of multiple genes
22. What is an example of a quantitative trait in animals?
a) Coat color in horses
b) Presence of wings in flies
c) Flower color in peas
d) Fur texture in dogs
Answer: a) Coat color in horses
23. Which of the following patterns is typically seen in polygenic inheritance?
a) A limited number of phenotypic categories
b) Continuous variation
c) A 3:1 ratio of phenotypes
d) One clear dominant phenotype
Answer: b) Continuous variation
24. The term “bell-shaped curve” in polygenic inheritance refers to:
a) A genetic model for Mendelian traits
b) The typical phenotypic distribution of polygenic traits
c) The number of genes involved in a trait
d) The dominance of alleles in polygenic traits
Answer: b) The typical phenotypic distribution of polygenic traits
25. Which of the following is an important aspect of quantitative inheritance?
a) Simple Mendelian inheritance patterns
b) A discrete number of phenotypic categories
c) Interaction between multiple genes
d) A single dominant gene controlling the trait
Answer: c) Interaction between multiple genes
26. In quantitative inheritance, the number of genes contributing to the trait usually correlates with:
a) The number of environmental factors affecting the trait
b) The complexity of the trait
c) The number of phenotypic categories
d) The size of the organism
Answer: b) The complexity of the trait
27. Which of the following traits shows continuous variation in humans?
a) Eye color
b) Fingerprint pattern
c) Height
d) Blood type
Answer: c) Height
28. The continuous distribution of phenotypic traits in a population results from:
a) Multiple alleles at a single gene locus
b) Multiple genes contributing to a single trait
c) A dominant allele controlling the trait
d) Environmental factors alone
Answer: b) Multiple genes contributing to a single trait
29. Which of the following is a significant feature of polygenic inheritance?
a) The trait will always be inherited in a 3:1 ratio.
b) Phenotypic traits controlled by many genes show a bell curve distribution.
c) Traits show no environmental influence.
d) Polygenic traits are governed by a single gene.
Answer: b) Phenotypic traits controlled by many genes show a bell curve distribution.
30. Which of these is an example of quantitative inheritance in plants?
a) Flower shape
b) Plant height
c) Petal color
d) Leaf shape
Answer: b) Plant height
These MCQs will help students understand the principles of polygenic traits and quantitative inheritance, which are essential concepts in genetics.
