Question

Two babies are accidentally interchanged in a hospital. Now which of the following combinations of husband and wife cannot win the case?

• A. O and AB
• B. A and O
• C. B and O
• D. A and B

Answer 1

The correct option is D A and B

Human blood group inheritance is the example of codominance and multiple alleles. It is governed by three alleles namely I${}^A$, I${}^B$ and I${}^O$. I${}^A$ and I${}^B$ show codominance while allele "I${}^O$" is recessive to both "I${}^A$" and "I${}^B$". This gives total six genotypes and four phenotypes- A (I${}^A$ I${}^A$ and I${}^A$ I${}^O$), B (I${}^B$ I${}^B$ and I${}^B$ I${}^O$) , AB (I${}^A$ I${}^B$) and O (I${}^O$ I${}^O$). Parents with O and AB blood group can have children with A and B blood group. Parents with O and A blood group can have children with A and O blood group. Parents with O and B blood group can have children with O and B blood group. But parents with A and B blood group can have children with A, B, AB and O blood group. Hence, they have least chances to win the case. Correct option is "D".