Question

A man with blood group A married a woman with blood group B. They have a son with AB blood group and a daughter with blood group O. Work out the cross and show the possibility of such inheritance.

Answer 1

For an O child, both parents must carry i: father Iᴬi and mother I^Bi. Cross: I^Ai × I^Bi. Offspring are I^AI^B (AB), I^Ai (A), I^Bi (B) and ii (O), each with probability ¼. Thus both stated children are possible.