What is the difference between codominance and incomplete dominance?
Genetics is an interesting subject to study since it helps an individual know the physical characteristics of plants and animals. This area of study can be understood by knowing both codominance and incomplete dominance.
However, the lesson provides a detailed insight into the difference between codominance and incomplete dominance with a comparison chart. The main aim of using the comparison table is to facilitate an easier understanding. Let’s find out:
What is Codominance?
Codominance is when both the parental phenotypes are expressed in the offspring when a cross is done between individuals of different phenotypes. This implies that neither of the alleles is dominant over the other.
The combination of these alleles results in the formation of a third allele which displays the traits from their parental phenotypes. These alleles produce their effect independently and can be observed in the offspring. Codominance example is the inheritance of the AB blood group.
What is an Incomplete Dominance?
Incomplete dominance results in the formation of a third phenotype which is a combination of both the parental alleles when a cross is done from an individual with two different phenotypes. The effect of the two parental alleles is more conspicuous but the alleles are not mixed together.
The two parental alleles are intermediate on the offspring and they can neither be observed in the offspring. Incomplete dominance examples are the inheritance of the height, weight, and eye color as well as pink snapdragon.
Comparison Chart: Codominance vs Incomplete Dominance
| Basic Terms | Codominance | Incomplete Dominance |
| Meaning | It is the appearance of both the parental alleles together on the offspring when a cross is done between an individual with two different phenotypes. | It is the appearance of the third phenotype on the offspring which occurs as a combination of both parental alleles when a cross is done between individuals with two different phenotypes. |
| Dominance | Both the alleles are equally conspicuous | One of the alleles is more conspicuous than the other |
| Mixing | Both parental alleles are mixed together to result in a third allele | The two parental alleles are not mixed together |
| Effect | Both parental alleles produce their effect independently | The parental alleles product intermediate effect on the offspring |
| Expression | Can be observed in the offspring | Neither is observed in the offspring |
| Quantitative/Qualitative Approach | Qualitative approach | Quantitative approach |
| Other features | No formation of a new phenotype | The offspring will have a new phenotype |
| Examples | The roan character of cows and the inheritance of the AB blood group | The pink snapdragon, the inheritance of the height, weight, eye color, and skin color |
Core Differences: Incomplete Dominance Vs Codominance
- Codominance is the appearance of both parental phenotypes in the offspring when a cross is done between two different phenotypes whereas incomplete dominance is the appearance of a third phenotype that occurs after a combination of the parental phenotype when a cross is done between two different phenotypes.
- The effect of both alleles in codominance is equally conspicuous whereas incomplete dominance, one of the parental alleles is more conspicuous than the other
- Codominance involves mixing together the parental allele to result in a third phenotype whereas incomplete dominance has nothing to do with the mixing of alleles
- The parental alleles in codominance produce their effect independently whereas incomplete dominance the effect of two parental alleles is intermediate on the offspring
- Both parental alleles in codominance can be observed in the offspring whereas incomplete dominance neither of the parental alleles can be observed.
- Codominance is a qualitative approach to gene expression whereas incomplete dominance is a quantitative approach of both incomplete dominant alleles
- Codominance examples are the roan character of cows and the inheritance of the AB blood group whereas incomplete dominance examples are the pink snapdragon, the inheritance of height, weight, eye color, and skin color.
Core Similarities between Incomplete Dominance and Codominance
- Both parental alleles are dominant
- Two parental alleles result in a third phenotype
- Both occur during the inheritance of a pair of heterozygous alleles.
- Both are caused by intragenic (allelic) gene interactions.
- Both cannot be explained by the laws of Mendelian inheritance.
Comparison Video
Summary
The core difference between codominance and incomplete dominance is that codominance is the appearance of both parental phenotypes in the offspring when a cross is done between two different phenotypes whereas incomplete dominance is the appearance of the third phenotype after a combination of parental phenotypes when a cross is done between two different phenotypes.