Question

Husband and wife belong to blood group O and AB respectively. Given below are blood groups of different children. Which of those cannot be of the said couple?

1: Blood group A

2: Blood group B

3: Blood group O

4: Blood group AB

• A. 1 & 2 only
• B. 3 & 4 only
• C. 4 only
• D. 2, 3 & 4 only.

Answer 1

The correct option is B

3 & 4 only

Allelic composition of husband is ii and that of wife is $I^A{I}^B$. Children can have one allele from both parents. Since father can contribute allele ‘i’ only, based on the allele from the mother the kids can be either $I^{A}ior{I}^{B}i$. That is only blood groups A or B are possible.