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.

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.


1) Which of the following is a possible partial genotype for the son?


A) IBIB
B) IBIA
C) ii
D) IBi
E) IAIA

Answer:  D


2) Which of the following is a possible genotype for the mother?


A) IAIA
B) IBIB
C) ii
D) IAi
E) IAIB

Answer:  D

3) Which of the following is a possible phenotype for the father?


A) A negative
B) O negative
C) B positive
D) AB negative
E) impossible to determine

Answer:  C


4) If both children are of blood type M, which of the following is possible?


A) Each parent is either M or MN.
B) Each parent must be type M.
C) Both children are heterozygous for this gene.
D) Neither parent can have the N allele.
E) The MN blood group is recessive to the ABO blood group.

Answer:  A