Interactions between alleles of one gene Dominance is a relationship between two alleles of the same gene. Several relationships are possible: complete dominance partial dominance incomplete dominance codominance overdominance Each relationship has particular characteristics.Interactions between alleles of one gene • Dominance is a relationship between two alleles of the same gene. • Several relationships are possible: • complete dominance • partial dominance/ incomplete dominance • codominance • overdominance • Each relationship has particular characteristics