Imagine that you are studying two parents who are considering having children. one parent is has the genotype iai and the other has the genotype ibi. create a punnett square to calculate the possible genotypes of their children.

Parent #1 has the alleles of  IA and i
Parent #2 has the alleles of IB and i
A punnet squares is a simple diagram that illustrates the possible genotypes of the offspring of these two people. 
Parent #1 is across the top and Parent #2 is along the side
        IA    i
IB    AB   IBi
i       IAi    ii

For IA or IB will be dominant to i. So for phenotype purposes their offspring have a 25% chande of being AB, 25% chance of B, 25% chance of A and a 25% change of type O (ii)

Might need you in a few weeks c: