Question

What type of genetic inheritance determines the ABO blood group system? What are the relations of dominance among the involved alleles?

Answer 1

Ans: Multiple allele inheritance (a type of non-Mendelian inheritance pattern that involves more than two alleles that usually code for a certain characteristic in a species) is found in the ABO blood group system of humans. The ABO blood grouping gene is found in chromosome 9. The four ABO blood groups, A,B,AB and O, arise from more than two alleles namely A,B,O.

There are three A,B,O blood group alleles, usually given the symbol I^A,I^B and i. I^A and I^B are codominant to each other, but are both dominant to i allele.