What is the Difference Between Codominance and Incomplete Dominance?

🆚 Go to Comparative Table 🆚

Codominance and incomplete dominance are both types of genetic inheritance that deviate from the standard dominant/recessive inheritance pattern. Here are the main differences between the two:

Codominance:

  1. Both alleles are simultaneously expressed in the heterozygote.
  2. Neither allele acts as dominant or recessive over the other.
  3. Individuals with blood group ABO exhibit codominance, where A and B are dominant in relation to O but not dominant against each other.
  4. Codominance results in a hybrid phenotype, where both parental phenotypes are expressed together in their offspring.

Incomplete Dominance:

  1. A dominant allele does not completely mask the effects of a recessive allele.
  2. The heterozygote phenotype is intermediate between the two homozygote phenotypes.
  3. An example of incomplete dominance is a cross between a homozygous white-flowered plant (WW) and a homozygous red-flowered plant (RR), which produces offspring with pink flowers (RW).
  4. Incomplete dominance results in a new phenotype, where the phenotypes of the two parents blend together to create a new phenotype for their offspring.

In summary, codominance involves the simultaneous expression of both alleles in the heterozygote, while incomplete dominance occurs when a dominant allele does not completely mask the effects of a recessive allele, resulting in a new, intermediate phenotype.

Comparative Table: Codominance vs Incomplete Dominance

Here is a table comparing the differences between codominance and incomplete dominance:

Feature Codominance Incomplete Dominance
Definition Codominance refers to the phenomenon where both alleles are simultaneously expressed in the heterozygote, and neither allele is dominant or recessive over the other. Incomplete dominance is a condition where a dominant allele does not completely mask the effects of the other allele, resulting in a new phenotype that is a combination of both.
Phenotype In codominance, the phenotype produced is different from the genotypes of the homozygotes, and both alleles are equally expressed. In incomplete dominance, the heterozygote phenotype is intermediate between the two homozygote phenotypes, creating a new phenotype.
Examples Codominance can be easily found in animals, plants, and humans, such as blood type. Incomplete dominance can be observed in plants like roses, where the allele for red color is dominant over the allele for white color, but the heterozygous flowers with both alleles are pink in color.

In summary, both codominance and incomplete dominance are types of genetic inheritance where alleles interact differently than the standard dominant/recessive model. In codominance, both alleles are simultaneously expressed, while in incomplete dominance, a new phenotype is created due to the blending of the two alleles.