Question

A person having genotype I^A I^B would show the blood group as AB. This is because of:

• A. Pleiotropy
• B. Codominance
• C. Segregation
• D. Incomplete dominance

Answer 1

The correct option is B

Codominance

The correct option is B:

Explanation of the correct answer:

1. Codominance is the phenomenon where two alleles express themselves independently when present together.
2. Due to this, the offspring resembles both parents.
3. Usually, this is observed in the ABO blood group.
4. As both A and B groups are dominant, it leads to the AB blood group.
5. Hence, an individual inheriting the A allele from the mother and the B allele from the father has a blood type AB.

Explanation of the incorrect options:

Option A:

1. Pleiotropy is the phenomenon in which a single gene may control more than one phenotypic trait.
2. It is seen in phenylketonuria.

Option C:

1. Segregation is when the alleles of a pair separate from each other such that a gamete receives only one of the two alleles.

Option D:

1. Incomplete dominance is when the phenotype of the F₁ is an intermediate of the two alleles from the parents in their homozygous state.
2. The offspring does not resemble either parent.

Final answer: A person having genotype I^A I^B would show the blood group as AB. This is because of codominance.