Question

If the blood groups of mother and father are AB and O, respectively, what are the blood groups possible for their child?

• A. AB or A
• B. AB
• C. A or B
• D. AB, A, B or O

Hint:

In ABO inheritance, O (ii) contributes no antigen. So when one parent is O, the child’s blood group depends only on the dominant alleles from the other parent.

Answer 1

The Correct Option is C

Step 1: Determine genotypes.
Mother (AB) → genotype I$^A$I$^B$
Father (O) → genotype ii
Step 2: Write possible combinations.
Cross I$^A$I$^B$ × ii → children genotypes: I$^A$i and I$^B$i
Step 3: Interpret phenotypes.
I$^A$i → blood group A
I$^B$i → blood group B
Step 4: Conclusion.
Possible blood groups = A or B.