Question

If the blood groups of the parents are $O^{+ve}$ and $A{B}^{+ve}$, the child with a normal genotype cannot show a blood group

• A. $A^{+ve}$
• B. $A{B}^{+ve}$
• C. $O^{+ve}$
• D. $A^{+ve}$ or $B^{+ve}$

Answer 1

The correct option is D $A^{+ve}$ or $B^{+ve}$

Let the father's blood group be AB${}^{+ve}$ and that of the mother be O${}^{+ve}$. The genotype of the father will be I${}^A$I${}^B$. Therefore the gametes will be I${}^A$ and I${}^B$. The genotype of the mother will be I${}^O$I${}^O$. The gamete will be I${}^O$. These gametes on crossing can give two possibilities I${}^A$I${}^O$ or I${}^B$I${}^O$. Thus the genotype of the child will be I${}^A$I${}^O$ or I${}^B$I${}^O$. So the child can have either blood group A${}^{+ve}$ or B${}^{+ve}$. The Rh factor of the child will be the same as that of its parents. Thus the correct answer is '$A^{+ve}$ or $B^{+ve}$'.