Question

Multiple allelism controls the inheritance of ___.

• A. Colourblindness
• B. Blood group
• C. Phenylketonuria
• D. Skin colour

Answer 1

The correct option is B Blood group

ABO blood grouping also provides a good example of multiple allelism. ABO blood groups are controlled by the gene I. The plasma membrane of the red blood cells has sugar polymers that protrude from its surface and the kind of sugar is controlled by the gene. The gene (I) has three alleles $I^A,I^B$ and i. The alleles $I^A$ and $I^B$ produce a slightly different form of the sugar while allele i does not produce any sugar. so, we see that more than two, i.e., three alleles, governing the same character. Since in an individual only two alleles can be present, multiple alleles can be found only when population studies are made.