Co-Dominance is a process, where two or more Dominant gene features can be shown in the animal body. In a simple process, the same dominant allele can be present in any combination. In those cases, the feature of the same Dominant alleles will be shown. Or sometimes, a combination can be formed with one recessive allele & one dominant allele. In those cases, as the dominant allele is present in the combination, the feature of the dominant allele will be shown. And if there are two recessive alleles are present, the feature of the recessive allele will be shown.
But in the case of the Co-Dominance, the process is completely different. Here, the rule for recessive is the same. This means if there are any recessive genes present in the combination they will be suppressed by the Dominant genes. Here, the uniqueness is under the combination of different two dominants. Two different dominants combine. In normal cases, this is not at all possible. But in the case of the Co-Dominance, this can be possible. In that case, all the features of those two dominant alleles will be shown to the animal body. All the two dominant genes will be in working condition there. Co-Dominance can only be found in the animal body. It is not possible in the plant body.
What Are Recessive & Dominant Alleles?
Scientists say that the evolution process comes due to mutation in the Generic Structure. But this statement is made on a very large field. If we consider small parts, we can able to notice that all the processes in the body, including Evolution, are going on with the help of Genes. Gene is one of the major genetic structures in the animal body. They are situated in the chromosomes. There are 48 pairs of chromosomes are present. Among them, 2 pairs belong to the sexual characteristics. All other chromosomes are involved in the body’s development process.
In those chromosomes the genes are present. In each gene, there are two different types of alleles are present. One of them is Dominant Allele & the other is the Recessive Allele. The function of the genes depends upon that allele. If in a combination of genes, two Recessive alleles are placed, then the result of the combination will be different. And in any combination, if there is any Dominant Alleles are present, then the feature of the Dominant allele will be shown. But, if two different dominant alleles are placed in the same combination, then the result might be different. There comes the Co-Dominance process.
Characteristics of Co-Dominance
There are some important characteristics of the Co-Dominance process. These are the main outline of the Co-Dominance process. Co Dominance is the process that mainly occurs in the animal body. But there is a slight presence of this process in the plant body also. Wherever the Co-Dominance process is occurring, it should follow the below-mentioned characteristics.
- Co-Dominance can only be found in Heterozygous combinations. All the alleles present there will show the features.
- In Co-Dominance, all the alleles that are present in that combination must be Dominant alleles. There will be no presence of the Recessive gene in the Co-Dominance process.
- The new offspring in the Co-Dominance process will resemble with its both parents. There will not be new traits present in that category of gene combination.
- The character of the offspring in Co-Dominance will be intermediate nature & will have all the traits of the parents.
- In the Co-Dominance, the phenotypic & genotypic ratio will always be the same.
Also Read: Mendel Law
Theory of Co-dominance and Multiple Alleles
Scientists have established the Co-Dominance theory with the help of the checkerboard. The Co-Dominance can only be seen in the animal body. But this can also be found in some plant genetic structures. But the count is very less there. For the theory of Co-Dominance, there is a need to create a checkerboard. For that purpose, two different allele combinations are taken here. In one case, there is an allele combination RR. This is the dominant allele combination that helps to develop Red colored skin in the animal. Also, along with that, there is another allele combination WW. This is also the dominant allele combination that helps to develop White colored skin in the animal.
Now, if there is hybridization happens between those two combinations, one different combination will be formed. Now, this combination can be termed Reddish White. And its genomic sequence will be RW. So, from this allele combination, we can see that it is Co-Dominance. Now, scientists have done selfing on those combinations. This means the RW combination is merging with the RW itself. As a result of the combination, it can be found from the checkerboard that, there will be three different combinations can be found.
One will be the Pure Red Colored Skin that is RR. Another will be the Pure White Colored Skin that is WW. And two will be Reddish White Colored Skin Animals that is RW. So, from this process, the theory of Co-Dominance is established. And the Phenotypic & Genotypic ratio will always be the same in Co-Dominance. In this case, the Phenotypic Ratio is 1:2:1. As there is one Red, two Reddish White & one White animal present. And the Genotypic Ratio will also be 1:2:1. So, so they are both the same in ratio number.
Importance Of Co-Dominance
It might seem that there is no importance of the Co-Dominance in nature. But, the Co-Dominance is very helpful for the existence of the species. The Co-Dominance is the process that comes as a sub-process of evolution. In the evolution process, a species doesn’t change to a new species within a small time. There is a chain of processes that needs to be executed. The Co-Dominance is that type of example. Co-Dominance helps to create variation in nature. If there is no variation in nature, then there will be no chance of the combination of the genes. So, the chance of the mutation process will be very less there. Co-Dominance helps to create new variations in the existing species. This will help to differentiate one species from another very easily. So, Co-Dominance might look unnecessary. But the importance of the process is much more.
Type of Interaction in Co-Dominance
Interactions are the most common basis for every evolutionary example. Every feature that occurs in a species is the result of a combination of different alleles. The dominant and recessive are also combinations of different alleles. Usually, this combination of different alliances is known as “Interaction.” And co-dominance is no different from that. In co-dominance, there is also interaction. This type of interaction is known as a heterogeneous interaction. Other than the heterogeneous interaction, another type of interaction is present. That is available while examining dominant and recessive genes.
Heterogeneous interaction means there will be two different features present. Suppose, in a heterogeneous interaction, one gene shows the result of black skin. On the other hand, another gene is showing results in white skin. The presence of both genes will appear as a heterogeneous interaction. But, in a dominant interaction, homogeneous interactions will be present. This means similar types of alleles will be present. That means both alleles will represent the same features. But in the case of heterogeneous interaction, two different traits must be present. And the presence of these true differences eventually helps to develop codominance among species. So the straight answer to the question will be the heterogeneous interaction that is present in the codominance.
Examples of Co-Dominant Traits
- Coat Color Of Animal: Different types of coat colors are one of the major examples of the Co-Dominance process. If the parents of the offspring have two different skin colors, then often time the offspring come with the Co-Dominance process. This means the offspring will have the presence of those two colors on its skin. If one of the parents has Red-colored skin & another has white-colored skin, then the offspring will have the presence of those two colors on its skin.
- Feather Color Of Birds: Similar to the coat color of the animal, the bird feather is also an example of the Co-Dominance. Co-Dominance is the reason for the colorfulness feather of different birds. In the case of the birds, two or more dominant alleles merge in combination. As a result, a bird may have a different number of colors in its feather. The parents of the offspring might have a different color combination. With the help of the Co-Dominance, all the colors will be present in the feather of the bird.
- Petal Color Of Plants: Co-Dominance is the process that can be mostly found in the animal body. That might be a mammal or a bird. But the Co-Dominance process is also present in the plant. But the number is very less. In the case of the plants, the petal of the flower depends upon the Co-Dominance process. A Red flower plant makes a hybrid with the White flower plant. As a result, with the help of the Co-Dominance process, the new offspring will have both colors in their petals. This also makes the flower of any plant colorful.
- Sickle Cell Anemia: In case of the Sickle Cell Anemia, the Co-Dominance process can be visualized. In normal Red Blood Cells, some gene alleles are present. That makes the Blood cells capable to carry oxygen. But in the case, of Sickle Cell Anemia, a dominant gene also merged with the gene combination. As a result, there will be the Co-Dominance process present. The new gene will make some changes in the shape of the Red Blood Cells. But as there was a dominant gene present earlier, there will be the trait of that dominant gene also. So, the Blood cells can carry oxygen there. But the shape of them will be changed due to Co-Dominance.
- Human Blood Group: The human blood group is the best example of the Co-Dominance process. In humans, there are three different genes are present. One is the A gene, one is the B gene & the last one is the O gene. A & B genes are dominant & O is the recessive one. If there is an A gene present along with the O gene, then the blood group will be A. If the B gene is present along with the O gene, then the blood group will be B. In case, A & B both dominant genes are present, then it will be the AB blood group. So, the AB blood group will be an example of the Co-Dominance.
FAQs on Co-Dominance
Question 1: What is Co-Dominance?
Answer:
Co-Dominance is a process in which two or more different dominant genes are present in the gene combination. And all the traits of those two or more dominant genes should be present in the body of the offspring. Two dominant alleles will be in active form.
Question 2: If a recessive allele is present in the gene combination, will it lead to the Co-Dominance?
Answer:
No, In the Co-Dominance, there is no provision to place any recessive allele in the gene combination. In the Co-Dominance, there can be only dominant alleles present.
Question 3: If only a dominant allele is present in the gene combination, will it lead to the Co-Dominance?
Answer:
No. The presence of a single dominant allele in the gene combination will not cause the Co-Dominance. In the Co-Dominance, there should be two dominant alleles are present. if there is only one dominant gene present, then it is an example of a normal gene combination.
Question 4: An offspring’s skin color only resembles its one parent’s skin color. Does it is an example of the Co-Dominance?
Answer:
No. The core concept of the Co-Dominance is, the offspring will have the traits of all the parents. The dominant alleles are always active in the Co-Dominance process. So, if the offspring’s skin color only resembles one parent, then it is an example of normal dominance.