Codominance

Co-dominance is a term used in genetics, ( = visible ) to describe the phenotypic of hereditary characteristics is used in organisms. For co-dominance is a prerequisite that an organism is diploid, at least - that has at least a double set of chromosomes (this is the case with most animals and plants). A further requirement is that the support (at least) has two different alleles of a gene. In this case, it is said that the support is heterozygous for the gene. So co-dominance can not occur if the two alleles completely identical to a gene (ie homozygous ) are.

This is called co-dominance, when the two different alleles of a single gene (ie, both the maternal and paternal ) in the heterozygous state equally strong influence on the phenotype. The phenotype does not arise here as a homogeneous hybrid of the two characteristics, as in the intermediate mode of inheritance, but the gene products of both alleles are fully expressed and the related features are independently marked.

An example of co-dominance is the inheritance of blood group AB of the AB0 system. If a person has both a genetic trait for blood group A, and one for the type B blood, the red blood cells have the blood group specific antigens of A and B. Against both blood groups no antibody thus formed. The blood type is AB so why Vollbluttranfusionen (considering the Rhesus factor ) of all blood types can be received. In contrast, the mode of inheritance of A and 0 and at B and 0 is dominant / recessive. A and B shall each by over the allele for 0. Another example of co-dominance is the lesser known MN blood group system.

• Inheritance