Genetics - Inheritance?

Question

A woman bears a child out of wedlock and sues a particular man for support of the child, claiming that he is the father. Blood typing shows that she is type A, her child is type O and the man is type B. The man says that this proves that he is not the father, but the judge says that it proves no such thing. Is the father or judge correct? Support using the Punnett square. What is the GR and PR?

Answer 1

The judge is right because the man and the woman can have their specific blood type but also be carrying the O blood type gene since O is reccessive and A/B are both dominant.

GR: 25% AB, AO, BO, OO
PR: 25% AB, A, B, O

___A | O
B| AB | BO
O| AO | OO

Answer 2

O is a recessive trait, A and B are codominant.

The possibilities for an A-blood parent are AA or AO. The possibilities for a B-blood parent are BB or BO.

So there you go. You can do the punnett square that will result in the possibility of an A-blood and B-blood pairing resulting in an O-blood child.