Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

Blood group 'O' corresponds to the homozygous recessive genotype $ii$.

For a child to have blood group 'O', they must inherit one $i$ allele from each parent. This means both parents must possess at least one $i$ allele in their genotype.

In the combination Father : $I^A{I}^B$ and Mother : $I^{A}i$, the father does not have an $i$ allele. Therefore, he can only pass either an $I^A$ or an $I^B$ allele to the offspring.

As a result, it is impossible for this couple to produce a child with the $ii$ genotype (blood group 'O').

In all other given combinations, both parents are heterozygous and possess an $i$ allele, making it possible for them to have a child with blood group 'O'.

Answer: Father : $I^A{I}^B$ and Mother : $I^{A}i$