Blood Typing and Pedigrees

What are the possible genotypes of a person with type A blood? Aa, Ao Aa, AA, Ao, AB AA, Ao AA, Aa, Ao What is the genotype of the original (first) parents if this is a recessive disorder we are tracking? HH x Hh Hh x Hh HH x hh Blood type has 3 alleles - A, B, and o. Which characteristic of alleles makes it possible to have a blood type of AB? incomplete dominance co-dominance multiple genes