For a person with blood group 'O', which of the following is not a possible combination of parents' blood group genotypes?
- Father : IA IB and Mother : IA i
- Father : IA i and Mother : IA i
- Father : IA i and Mother : IB i
- Father : IB i and Mother : IB i
Answer
(1) Father : IA IB and Mother : IA i
Solution
A person with blood group O has the genotype ii, so he must receive one i allele from each parent.
(1) Father IA IB gives only IA or IB, never i ⇒ an O child is not possible.
(2) IA i IA i ⇒ 14 children ii (O) — possible.
(3) IA i IB i ⇒ 14 children ii (O) — possible.
(4) IB i IB i ⇒ 14 children ii (O) — possible.
Answer: (1)