Question

An individual with an AB genotype exhibits two separate molecules of A and B on their red blood cell membranes. This expression is an example of codominance.

Option 1: True
Option 2: False

Answer 1

An individual with AB blood type expressing both A and B molecules on their red blood cell membranes is a true example of codominance, where both IA and IB alleles are expressed equally.

Step-by-step explanation:

The expression of both A and B molecules on the red blood cell membranes in an individual with an AB genotype is indeed an example of codominance. This genetic phenomenon is characterized by the simultaneous and distinct expression of the alleles for both A and B antigens. In the ABO blood group system, the alleles IA and IB are codominant, and when inherited together, they result in the AB blood type, with no blending of features as seen in incomplete dominance. The allele i, which leads to type O blood, is recessive to both IA and IB. Thus, a heterozygous individual for A and B blood types (IAIB) will express both A and B antigens equally on their erythrocytes, confirming the codominant inheritance pattern.