Question

Explain codominance with a suitable example.

Answer 1

In codominance, both alleles are expressed equally in the heterozygous condition. Neither allele is dominant or recessive over the other. Instead of blending, both parent phenotypes appear together in the offspring.

Example: ABO Blood Group System

• In humans, blood group A and blood group B alleles are codominant with each other.
• If an individual inherits the A allele from one parent and the B allele from the other, their blood type will be AB.
• In this case, both A and B antigens are expressed on the surface of red blood cells, showing codominance.
• However, the O allele is recessive, meaning individuals with AO or BO genotypes will have A or B blood types, respectively.