It is commonly found in plants and animals having more than one pigment color. For example, if we cross a red and white flower with a codominant pattern, the offspring flower will have red and white patches. This type of relationship between alleles is called codominance.
How Does Codominance Work
Other Examples of Codominance
Codominance vs. Incomplete Dominance
Self-pollination of the codominant F1 plants produces offspring with phenotype 1 red: 2 red/white: 1 white. Thus, alleles are still inherited according to Mendel’s laws, even when they show codominance.
Codominance Punnett Square
To understand the mechanism of codominance and verify if it follows Mendel’s laws of inheritance, the botanists use Punnett square as shown below: The result thus shows codominance in 100% of F1 offspring and 50% of F2 offspring. Individuals homozygous for the M allele have M as the RBC antigen. Similarly, organisms homozygous for the N allele have N as the RBC antigen. Heterozygotes (LM LN) have both types of markers expressed equally on the surface of the RBCs.
ABO Blood Grouping in Humans
Persons with type AB blood have one allele for A and the other for B that are dominant. In contrast, the O allele is recessive, and thus its expression is masked by the expression of the other alleles. The altered hemoglobin that causes sickle-celled anemia is inherited as a codominant trait. Heterozygous individuals express normal and sickle hemoglobin, so they have a mixture of normal and sickle red blood cells.
Codominance in Other Animals
Speckled chickens have alleles for both black and white features.Roan cattle have alleles for both red hair and white hair.
Codominance in Plants
Rhododendrons express red and white color flower petals simultaneously.
What is the Difference between Codominance and Incomplete Dominance
In codominance, both parental phenotypes are expressed together in the offspring. In contrast, in incomplete dominance, the two parental phenotypes blend to form a new phenotype for their offspring. Some other common differences are:
