C O N T E N T SSee AlsoDefinitionCodominance occurs when two alleles of a gene produce two distinct and detectable gene products. A good example of this is found in human MN blood typing. Within the MN blood groups, there are are two antigens, M and N whose production is determined by a gene with two alleles, LM and LN. LM confers the ability to produce the M antigen, while LN confers the ability to produce the N antigen. Individuals who have the genotype LM LM will have only the M antigen on their red cells, and will be type M. Individuls with the genotype LN LN will have only the N antigen on their red cells, and will be type N. Heterozygotes (LM LN) produce both antigens, and are type MN. Codominance is also apparent in human blood types. A person with one "A" blood type allele and one "B" blood type allele would have a blood type of "AB". Note that in the case of codominance, both alleles contribute equally to the phenotype. This is the major difference between codominance and incomplete dominance. With incomplete dominance, the two alleles did not contirbute equally to the phenotype: the W allele contributed red pigment, but the w allele contributed nothing to flower color. DiscussionIncomplete dominance occurs when certain of the recessive gene appears within the phenotype of the organism, causing a blend in between both the dominant and recessive gene. Attribution
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