table 1.3 shows the possible allelic combinations,the resulting phenotyp and a description of the mode of inheritance.
The allele A and B show equal dominance with respect to each other,i.e. they are co-dominant,but each is dominant to O.Only two of the three alleles can be present in an individual.Table 1.3 shows the possible genotypes one can have.for blood group AB,both type A and B antigens are present on the red blood cell membrane.