Blood Type Problems #2 ‐ KEY
1. List all the possible genotypes for each of the 4 blood types:
Type O _____OO_______
Type A _____AA, AO_______
Type B _____BB, BO_______
Type AB ___AB_________
2. A man with AB blood is married to a woman with AB blood. What blood types will their children be
and in what proportion?
1/4 AA or type A Blood
1/4 BB or type B Blood
1/2 AB
3. A man who has type B blood (genotype: BB) is married to a woman with type O blood. What blood
type will their children have?
All will have genotype BB, and be type B Blood
4. A woman with type A blood (genotype: AO) is married to a type B person (genotype: BO). What
blood types will their children have?
1/4 will by AB, type AB blood; 1/4 will be AO, or type A Blood; 1/4 will be BO, or type B blood; 1/4 will
be OO, type O Blood
5. A woman with type A blood is claiming that a man with type AB blood is the father of her child,
who is also type AB. Could this man be the father? Show the possible crosses; remember the woman
can have AO or AA genotypes.
It is possible. The mother can be either AA or AO and still produce a child with type AB blood from
that father.
6. A man with type AB blood is married to a woman with type O blood. They have two natural
children, and one adopted child. The children's blood types are: A, B, and O. Which child was
adopted?
The O child was adopted, even though the mother is type O, the father will contribute an A or a B
allele to the offspring. These alleles are dominant.