Inheritance of ABO blood group is
Inheritance of ABO blood group is Codominance.
"Although Mendelian traits are usually described as dominant or recessive, in some cases both of the alleles
of a gene pair contribute to the phenotype—a condition called codominance. Histocompatibility and
blood group antigens are good examples of codominant inheritance. "
Codominance is a relationship between two versions of a gene, individuals receive one version of a gene,
called an allele, from each parent. If the alleles are different, the dominant allele usually will be
expressed, while the effect of the other allele, called recessive, is masked. In Codominance, however,
neither allele is recessive nor are the phenotypes of both alleles are expressed, e.g., ABO blood group,
where in AB blood group both A and B are dominant."
Codominance: When both alleles of a gene pair contribute to the phenotype. E.g., Blood group AB.