Question

A woman who has the blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible genotype for the mother?

IAi
IAIB
IAIA
IBIB
ii

Answer 1

IAi

If the son has o blood then

1. Mother and FATHER must have an o allele.
2. Then we know that the mom has A blood, so the father probably has B blood

I hope this helps