Identify the wrong statement with reference to the gene ‘I’ that controls ABO blood groups.
- Allele ‘i’ does not produce any sugar.
- The gene (I) has three alleles.
- When IA and IB are present together, they express same type of sugar.
- A person will have only two of the three alleles.
Answer
(3) When IA and IB are present together, they express same type of sugar.
Solution
As per NCERT, the gene I has three alleles IA, IB and i; a diploid person carries any two of them.
IA and IB produce slightly different forms of the sugar, while allele i does not produce any sugar.
IA and IB are co-dominant: when present together, both express their own types of sugars (blood group AB).
∴ Statement (3) is wrong.
Answer: (3)