A man with blood group A marries AB blood group woman. Which type of progeny indicate that the man is not homozygous?
AB
B
A
O
Correct answer: B
Solution
If the man were homozygous AA, he could pass only A alleles, so with an AB mother the children could be A, AB, or B? No—B would require the father to contribute i. Therefore a B child shows the father must be heterozygous AO.