Gametes IAI IAIB
| IA | I |
IA | IAIA | IAI |
IB | IAIB
| IBI |
On the other hand, a cross between homozygous man with A blood group, IAIA and woman of AB blood group, IAIB produce progeny with A, AB blood groups, none of the child will have B blood group.
Gametes IAIA IAIB
| IA | IA
|
IA | IAIA | IAIA |
IB | IAIB
| IAIB |
Hence, a child with B blood group would indicate that man is heterozygous A.