Answer:
Codominance
Explanation:
According to the given information, an individual carries one allele for blood group A antigen and one allele for the blood group B. Let's assume that the allele I^A imparts blood type "A" while the allele I^B is responsible for blood type B. Now, the genotype of the individual is I^AI^B and its phenotype is blood type "AB".
When both the alleles of a gene are expressed in a heterozygote and the phenotype of the heterozygote is distinct from both the pure breeding parents, the pattern of inheritance is called codominance. The I^A and I^B alleles codominant as both are equally expressed in the heterozygote.
