Refers to a situation where there is nothing in the two alleles from the parent in charge. Therefore, the heterozygous phenotype is not the same for any parent. In such cases, heterozygotes. Example - When red snapdragons contrast pollen with white snapdragons, they result in pink snapdragons. This is because there are no red or white alleles of the flower.

When both alleles manifest themselves together in an individual it is called codominance.