Use the following information to answer the questions below.
A woman who has 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 the probable genotype for the mother?
Use the following information to answer the questions below.
A woman who has 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 the probable genotype for the mother?
A) IAiRr
B) IAirr
C) IAiRR
D) IAIARR
E) IAIARr

The woman has A blood type which means she can either be IAIA or IAi. Since the daughter has the recessive O blood type ( ii ) it means that she must have obtained one "i" allele from her mother. Hence, mother's genotype is IAi.

The woman has Rh+ blood type which means she can either be RR or Rr. Since the son has recessive negative blood group ( rr ) it means he must have obtained one "r" allele from his mother. Hence, mother's genotype is Rr.

So her collective genotype for blood group will be IAiRr.