Table of Contents
Incomplete Dominance
Incomplete Dominance – Basic Concept: In incomplete dominance, the heterozygote has a phenotype that is intermediate between the two homozygotes. This occurs because the dominant allele is not completely dominant over the recessive allele.
What Is the Law of Complete Dominance?
The law of complete dominance states that when two alleles for a particular gene are present in a diploid organism, one of the alleles is always expressed and the other is not expressed. The allele that is expressed is called the dominant allele, and the allele that is not expressed is called the recessive allele.
Let us Examine What is Incomplete Dominance:
Incomplete dominance is a type of genetic interaction in which the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes. Incomplete dominance is also known as partial dominance.
Incomplete dominance occurs when the expression of one allele is not completely dominant over the other allele. This results in a heterozygote with a phenotype that is intermediate between the two homozygotes. For example, the allele for red flowers (RR) is incompletely dominant over the allele for white flowers (WW). This means that a plant with the RR allele will have flowers that are red, but a plant with the WW allele will have flowers that are white. The phenotype of a heterozygote (Rr) will be somewhere in between the phenotypes of the two homozygotes.
Incomplete Dominance
Incomplete dominance (also called epistasis) is a situation where the phenotype of a heterozygote is not intermediate between the phenotypes of the two homozygotes, but is instead a third, distinct phenotype. This occurs when the genes that control the phenotype are not completely dominant or recessive. Incomplete dominance is also called heterosis, hybrid vigor, or heterozygous advantage.
Codominance
In genetics, codominance is a pattern of inheritance in which the alleles for two genes are both expressed phenotypically. This occurs when the dominant allele of one gene masks the recessive allele of the other gene.
In other words, codominance is a pattern of inheritance in which both alleles for a gene are expressed. This occurs when the dominant allele of one gene masks the recessive allele of the other gene.
Incomplete Dominance vs Codominance
Incomplete dominance and codominance are two different ways that alleles can be expressed in a heterozygote. Incomplete dominance is when the dominant allele and the recessive allele are both expressed in the heterozygote, but the dominant allele is expressed to a lesser degree than the recessive allele. Codominance is when both alleles are expressed in the heterozygote and they are both expressed equally.
Mechanism of Incomplete Dominance
Incomplete dominance is a type of genetic variation in which the phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes. This occurs when one allele is not completely dominant over the other. Incomplete dominance is also known as codominance.
Examples of Incomplete Dominance in Human Traits
There are many human traits that are incompletely dominant. Examples of incompletely dominant human traits include height, eye color, and hair color. In general, incompletely dominant human traits are determined by a combination of genetic and environmental factors.
Examples of Incomplete Dominance in Animal Breeding
Examples : of incomplete dominance in animal breeding can be found throughout the animal kingdom. One common example is the inheritance of coat color in horses. A horse may be a solid color, meaning that its coat color is all one color. However, horses may also be a mix of colors, meaning that their coat has two or more colors. Incomplete dominance is responsible for the inheritance of these mixed colors.
Another example of incomplete dominance can be found in the breeding of dogs. Dogs may be bred to create a variety of colors, including black, white, and brown. However, dogs may also be bred to create a variety of markings, including spots, patches, and stripes. Incomplete dominance is responsible for the inheritance of these markings.
FAQs
Q: What is incomplete dominance?
A: Incomplete dominance is a genetic concept where the phenotype of a heterozygous individual is an intermediate blend of the phenotypes of the two homozygous individuals.
Q: How does incomplete dominance differ from complete dominance?
A: Incomplete dominance differs from complete dominance because in incomplete dominance, the heterozygous phenotype is a blend or mixture of the two homozygous phenotypes, while in complete dominance, one allele completely masks the expression of the other.
Q: What are examples of incomplete dominance?
A: Examples of incomplete dominance include the flower color in snapdragons (red and white alleles produce pink flowers in heterozygotes) and the coat color in some breeds of cattle (red and white alleles produce roan-colored individuals).
Q: How is incomplete dominance represented in Punnett squares?
A: In Punnett squares, incomplete dominance is represented by using capital letters to represent alleles. For example, if the red allele is represented by “R” and the white allele is represented by “W,” the heterozygous genotype would be represented as “RW” in a Punnett square.
Q: Can incomplete dominance lead to new alleles?
A: No, incomplete dominance does not lead to the creation of new alleles. It is a phenomenon that occurs due to the interaction of existing alleles.
Q: Is incomplete dominance common in nature?
A: Incomplete dominance is relatively common in nature and can be found in various organisms, including plants, animals, and humans.
Q: How does incomplete dominance affect inheritance patterns?
A: Incomplete dominance affects inheritance patterns by producing an intermediate phenotype in heterozygotes, which can result in a 1:2:1 phenotypic ratio in the offspring of a cross between two heterozygous individuals.
Q: Can incomplete dominance occur in multiple genes?
A: Yes, incomplete dominance can occur in multiple genes. In such cases, the phenotypic ratios may become more complex due to the interaction of multiple incomplete dominant alleles.
Q: Can incomplete dominance be influenced by environmental factors?
A: While incomplete dominance is primarily determined by genetic factors, environmental factors can sometimes influence the expression of incomplete dominance. External conditions may affect the degree of expression or the appearance of the intermediate phenotype.
