In humans there is a locus for blood type on Chromosome 9. There are three alleles, A, B and O. Alleles A and B are codominant but A and B are dominant to O blood type. Based on the phenotypes presented below, decide whether the offspring phenotype is possible given the parents' phenotypes:

Offspring phenotype is O when one parent is A and the other is B (true = possible, or false=not possible)

Human blood type is determined by co-dominant alleles. An allele is one of several different forms of genetic information that is present in our DNA at a specific location on a specific chromosome. There are three different alleles for human blood type, known as IA, IB, and i. For simplicity, we can call these alleles A (for IA), B (for IB), and O (for i). Each of us has two ABO blood type alleles, because we each inherit one blood type allele from our biological mother and one from our biological father. A description of the pair of alleles in our DNA is called the genotype. Since there are three different alleles, there are a total of six different genotypes at the human ABO genetic locus. The different possible genotypes are AA, AO, BB, BO, AB, and OO.