For the ABO system of blood groups, allele IA produces N acetylgalactosamyl transferase enzyme which recognizes H antigen present in RBC membrane and adds N-acetylgalactosamine to sugar part of H antigen to form A antigen. The allele I^{B }produces galactosyl transferase enzyme which adds galactose o the sugar part of H antigen to form B antigen. Allele 'i' does not produce any sugar or antigen. When both IAand IB are present in a person, both enzymes thus both antigens A and B are produced. This is because of co-dominance. These antigens determine the type of AB blood group.
Identify the wrong statement with reference to the gene ‘I’ that controls ABO blood groups.
NEET UG 2020 — Zoology Principles of Inheritance and Variation
2020mcqmedium
Identify the wrong statement with reference to the gene ‘I’ that controls ABO blood groups.
Official previous-year question
Held on 30 Apr 2020 · Verified 9 Jul 2026.
Options
- A
A person will have only two of the three alleles.
- B
When IA and IB are present together, they express same type of sugar.
- C
Allele ‘i’ does not produce any sugar
- D
The gene (I) has three alleles.
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