Question

“The influence of both the alleles in a heterozygous state is clearly expressed in codominance.” Explain with the help of inheritance of ABO blood group in humans.

Hint:

Codominance allows the expression of both alleles simultaneously, demonstrating a unique pattern of inheritance.

Answer 1

When both alleles in a heterozygous individual are expressed to an equal degree, this phenomenon is termed codominance. A prime illustration is the ABO blood group system. Within this system, the IA and IB alleles exhibit codominance, whereas the i allele is recessive. An individual possessing the IAIB genotype will have an AB blood group due to the simultaneous expression of both the IA and IB alleles.