Co-dominance in Genetics

What is the main characteristic of co-dominance in the F₁ generation?

Which gene controls the ABO blood grouping in humans?

When allele i is present with either IA or IB, what is the outcome?

How many different combinations of genotypes for the human ABO blood type can result from the three alleles?

What happens when both IA and IB alleles are present in an individual?

Co-dominance in Genetics

Co-dominance results in the F₁ generation exhibiting traits from both parents, contrasting with classical dominance or incomplete dominance.
Human ABO blood type is a prime example of co-dominance, controlled by the gene I.
The gene I has three alleles: IA, IB, and i.
Alleles IA and IB produce distinct forms of sugar on the surface of red blood cells, while allele i results in no sugar production.
In diploid organisms like humans, an individual inherits two of the three possible alleles, leading to various combinations.
Alleles IA and IB are completely dominant over allele i, meaning that when combined with i, only the sugar-producing allele is expressed.
When both IA and IB are present, both sugars are produced, demonstrating co-dominance.
This leads to red blood cells having both A and B sugars when IA and IB are paired.
The presence of three alleles allows for six different combinations, resulting in six distinct genotypes for ABO blood type.
Six possible genotypes lead to four observable phenotypes: A, B, AB, and O blood types.

Explore the concept of co-dominance in genetics through this quiz. Understand how co-dominance differs from classical and incomplete dominance, and learn about the role of alleles in determining blood types. Test your knowledge of human ABO blood types and the genetic mechanisms involved.