What is the difference between the terms dominant and codominant

Now these three different dominance patterns change when we look at the heterozygous example. That's what makes these three patterns different. Now we're already familiar with the example of complete dominance, so if we said that the red R is dominant over the blue R then this would make the heterozygous phenotype a red flower for complete dominance. Now what co-dominance is, is when the heterozygous phenotype shows a flower with some red petals and some blue petals. So it's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype.

Now what incomplete dominance is, is when the heterozygous phenotype shows a mixture of the two alleles. So in this case the red and blue flower petals may combine to form a purple flower. Neither allele is completely dominant over the other and instead the two, being incompletely dominant, mix together.

So what did we learn? Well, if we assume the heterozygous genotype, red R, blue R, then there are three different dominance patterns that we might see for a specific trait.

Leave a Reply Cancel reply Your email address will not be published. Dominance vs Codominance. Dominance is a relationship between two alleles in which dominant allele suppresses the effect of recessive allele during the expression. Codominance is a form of dominance in a heterozygous in which both alleles independently show the effect of the allele on the final phenotype.

Traits of Phenotype. Effect of the dominant allele is shown in the phenotype. Effects of both alleles are clear in the codominance. Expression of Alleles. One allele is expressed fully while the other allele is suppressed. Both alleles are expressed fully in the codominance state. Masking Effect. One allele completely masks the effect of the other allele. Neither allele completely masks the other.

Phenotype is dominant. Phenotype is neither dominant nor recessive. Half the offspring would be pink Rr , a quarter would be red RR , and a quarter would be white rr as you can see in the Punnett square below. Cows with the genotype BB are completely black, those with the genotype WW are completely white, and when they are crossed, cows with the genotype BW have black and white spots across their body. When doing a cross that follows codominance inheritance patterns, all capital letters are usually used to represent the alleles to show no allele is dominant over the other.

Below is a Punnett square showing what happens when you cross a pure black cow BB with a black and white spotted cow BW. From the Punnett square, you can see that half of the offspring will be pure black, and the other half will have black and white spots. Incomplete dominance is when the phenotypes of the two parents blend together to create a new phenotype for their offspring. An example is a white flower and a red flower producing pink flowers. Codominance is when the two parent phenotypes are expressed together in the offspring.

An example is a white flower and a red flower producing offspring with red and white patches. Interested in finding out more about genetics and molecular biology? We have articles that go over nucleotides, the building blocks of DNA , as well as explanations of how mitosis works and how it differs from meiosis. Fine with the big concepts of cellular biology but need help with memorizing what different structures are and do?

Start with an overview of animal cells , then drill down to learn the nitty gritty of cell vacuoles , the cell membrane , and the endoplasmic reticulum. Need help with other biology concepts? In genetics, Dominance is a relationship between alleles of one gene. In order to understand the concept of the dominance of alleles, we need to know more about genes. So far we know that genes are a hereditary unit in organisms which exist as a pair of alleles in diploid organisms.

These pairs of alleles may or may not be similar. That is, a heterozygous gene has two dissimilar pairs of alleles while homozygous have identical ones. Heterozygous alleles carry different information on traits. When we say one trait is dominant over the opposite , there are often two reasons:.

Incomplete Dominance and Codominance. Incomplete dominance and codominance are different from one another. In codominance, both the alleles present on a gene are expressed in the phenotype.

A flower showing codominance will have patches of red and white instead of a uniformly pink flower.