What are the possible genotypes for a person with type A blood or type B, or type AB or type O?

The ABO blood group is the case of co-dominance or multiple allelism. Co-dominance may be defined as a non Mendelian inheritance in which both the alleles can express themselves in the heterozygous condition.

The person with blood type A has two possible genotypes with IA IA or IA i.

The person with blood type B has two possible genotype with IB IB or IBi.

The person with blood type has genotype of IAIB.

The person with blood type O has possible genotype is ii.

Thus, there are total six possible genotype of blood group exist in human population.