250+ TOP MCQs on Inheritance Principles – Multiple Allelism and Answers

Biology Multiple Choice Questions on “Inheritance Principles – Multiple Allelism”.

1. A case was registered against the progeny being exchanged at the hospital. The doctors used blood groups to solve the case. The blood group genotype of parents was IAi and IAIB. What was the blood group of the child who was wrongly placed as their child?
a) A
b) B
c) AB
d) O
Answer: d
Clarification: The progeny of these parents can have IAIA, IAIB, IAi, and IBi. Thus, the progeny can have either A, B, or AB blood groups. The progeny with O blood group will be the only case that can be solved simply based on blood groups.

2. The combinations of alleles of ABO system give rise to six phenotypes.
a) True
b) False
Answer: b
Clarification: The ABO system has three alleles IA, IB, and i. The number of phenotypes produced by these alleles is only three.

3. The combinations of alleles of ABO system give rise to six genotypes.
a) True
b) False
Answer: a
Clarification: ABO blood system is comprised of alleles IA, IB, and i. These alleles can pair up to produce up 6 combinations. This accounts for the 6 genotypes observed.

4. What mode of inheritance involves more than two forms of gene giving rise to a repertoire of phenotypes?
a) Complete dominance
b) Incomplete dominance
c) Codominance
d) Multiple allelism
Answer: d
Clarification: In multiple allelism, more than one allele can be present at a locus. This results in the production of many different phenotypes.

5. To discover multiple allelism, it is essential to study _______
a) cells from an individual
b) organs from an individual
c) tissues from an individual
d) population
Answer: d
Clarification: An individual can have a maximum of two alleles. Hence to study multiple allelism, it is essential to sample a large chunk of the population.

6. The mode of inheritance depends on _______
a) gene
b) genotype
c) phenotype
d) organism
Answer: c
Clarification: The mode of inheritance depends on the phenotype. A single gene can give rise to different phenotypes, with each phenotype showing a different mode of inheritance.

7. Which of the following is the only possible blood group of progeny obtained from parents that have IAIA and IBIB as their genotypes?
a) A
b) B
c) AB
d) O
Answer: d
Clarification: The only possible allele that can be produced by IAIA parent is IA. Similarly, the only possible allele that can be produced by IBIB parent is IB. The progeny produced will have the alleles IA and IB. Thus, their blood group will be AB.

8. What will be the blood group of a person who has ii as the genotype?
a) A
b) B
c) AB
d) O
Answer: d
Clarification: The present of ii as the genotype results in no sugar antigen being expressed by the RBC. Thus, the blood group of the progeny is O.

9. If the blood group of an offspring is O, which of the following is not the correct parental genotypes?
a) IAIA, IAIB
b) IAi, IAi
c) IAi, IBi
d) ii, ii
Answer: a
Clarification: The blood group O is encoded by ii. Thus, of the given options, only IAIA, IAIB parental pair cannot produce ii infants.

10. What is the blood group of the progeny if one parent donates IA allele while the other donates i?
a) A
b) B
c) AB
d) O
Answer: a
Clarification: The progeny has one copy of IA and one copy of i. IA is dominant over i. Thus, only IA will be expressed. This will result in A blood group.