Why is the human ABO blood group gene considered a good example of multiple alleles?
A B O blood groups are controlled by a single gene: (I) The plasma membrane of the red blood cells has sugar polymers that protrude from its surface and is controlled by the gene. The gene (I) has three alleles lA, lBand lO. Presence of more than two types of alleles at the same locus governing the same character is called multiple alleles.
