This photograph shows a person with a dimple. Having dimples is a dominant trait. A person who has a dimple can either by homogenous (DD) or a hybrid (Dd). A person who doesn’t have a dimple must have two of the recessive alleles (dd). Some traits, such as hair type, show incomplete dominance in which the hybrid version shows a blend of the dominant and recessive phenotypes. Codominance is when both alleles are equally dominant and thus the phenotype shows a mixture where both traits are equally visible. An example of codominance is blood type AB.