3. The ABO blood type is controlled by a single locus, called I, with alleles IA, IB, and IO.
These give rise to the blood type phenotypes, A, B, AB, and O.
a. Suppose that parents know their phenotypes: the father is type AB and the mother is type
O. What are the genotypes of these parents?
b. What are the possible blood type phenotypes among their children?
c. Suppose that the father is type A and the mother is type B, and we don’t have any data
about their genotypes. What are the possible blood types among their children?