Question

Man with blood group A , marries a women with blood group B , what will be there baby blood group?

Answer 1

ABO blood groups are controlled by gene I. Gene I has three alleles, I ^A, I ^B and i.

• A person possesses any two of the three alleles. I^A and I ^B dominate over i. But with each other, I ^A and I ^B are co-dominant.
• Thus I ^AI ^A or I ^Ai means blood group A, I ^BI ^B or I ^Bi means blood group B. I ^AI ^B means blood group AB and ii means blood group O.

So, a Man with blood group A can have either I ^AI ^A genotype or I ^Ai genotype. Woman with blood group B can have either I ^BI ^B or I ^Bi genotype. Each parent can contribute any one allele to the child.

So blood group of child can be :

Allele From Dad	Allele From Mom	Genotype of baby	Blood group of baby
I A	I B	I A I B	AB
I A	i	I A i	A
i	I B	I B i	B
i	i	i i	O