Question

Human blood groups are governed by three alleles, IA, IB, and i. IA and IB are codominant and i is recessive to both. A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes?

Answer 1

They could have all four type phenotype that are A, B, AB, and O

Explanation:

If the man has A blood group and the woman has B blood group then the genotype of man can be IAIA or IAi and the genotype of woman can be IBIB or IBi.

IA i

IB IAIB IBi

i IAi ii

So if the genotype of the parents are IAi and IBi then out of four offspring one could have AB blood group, second could have B blood group, third could have A blood group and fourth could have O blood group as shown in the cross above.