Question

If a child has O type of blood group and the father B type, what will be the genotype of the father ?

• A. I I
• B. I${}^A$I${}^B$
• C. I I${}^B$
• D. I I${}^A$

Answer 1

Answer: (C)

I I${}^B$

ABO blood group system, the classification of human blood based on the inherited properties of red blood cells (erythrocytes) as determined by the presence or absence of the antigens A and B, which are carried on the surface of the red cells. Persons may thus have type A, type B, type O, or type AB blood.

Therefore if a father has blood group B (I${}^B$I${}^B$ or I${}^B$I) and child has blood group O (II), then father should have genotype of I${}^B$I.

Child with blood group O will have genotype II. It is a recessive genotype. Thus, the genotype of father will obviously have a recessive 'I' allele and the genotype will be I${}^B$ I.