What is the probablity of a child having a type AB blood if one of the parents is heterozygous for A blood?

Question

and the other heterozygous for B? What other genotypes are possible for this child?

Answer 1

if one parent is heterozygous for A, then they are AO;
if the other parent is heterozygous for B, then they are BO,
therefore, the parents could have a child that is either: AB, AO, BO, or OO. So, the probability of having a child that is AB is 1 out of 4 or 25%.

I assume that your statement "heterozygous for A blood" means that they are type A and not AB, Is this correct?

Answer 2

Heterozygous just means that the two alleles are not alike.

One parent is heterozygous for Type A: AB or AO.
One parent is heterozygous for Tyep B: BA or BO.

In order for the child to be Type AB, the child must get the A allele from one parent (1/2 chance) and the child must get the B allele from the other parent (1/2 chance).

The probability of getting A AND B is 1/2 * 1/2 = 1/4 or 25%. Saying "and" in a probability question means you have to multiply.

Other possible genotypes from these parents:

AO or AB crossed with BO or BA.
You can see that a child could get these additional genotypes by taking one allele from each parent: AA, AO, BB, BO, OO

Answer 3

If parent 1 AO and parent 2 is BO (since O is the only possiblity)
AO x BO
Offpring probabilities are
AB, AO, BO, OO
So 25% of being AB, A, B (heterozygous) and OO..one of each blood type!!