Question

One gene that influences blood type in humans is the ABO blood group system. There are 3 alleles: I^A, I^B, and i, that are co-dominant or dominant to one another. For each cross below, indicate the phenotypes and ratios of the expected offspring:

a) I^B i male crossed to i i female

b) I^A I^B male crossed to i i female

c) I^A I^A male crossed to I^A i female

d) I^B i male crossed to I^B i female

e) I^B i male crossed to I^A i female

Answer 1

IA and IB alleles are codominant to each other and results in AB type blood group. IA and IB are dominant to i and results in A and B type of blood group and ii allele results in O type blood group.

The respective crosses are shown below with their phenotypes and genotypes ratios:-