Genetics and Inheritance of the ABO System The inheritance pattern of the ABO blood group exhibits codominance. 3 alleles: A and B are dominant alleles, O is a recessive allele. 6 genotypes: AA, AO, BB, BO, AB, OO 4 phenotypes: A, B, AB, O - Dr. Eric Strong @DrEricStrong - Strong Medicine https://www.youtube.com/c/EricsMedi #Blood #ABO #System #Genetics #Inheritance #hematology #diagnosis