According to the concept of incomplete dominance, a heterozygous person with the alleles for blood type A and B will have blood type O.

Incomplete Dominance

A genetic phenomenon in which a dominant allele does not completely mask the effects of a recessive allele, resulting in a third, often blended phenotype.

Heterozygous

A genetic condition where an individual has two different alleles at a gene locus.

Blood Type

A classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells, which can affect blood transfusions compatibility.