What are multiple alleles? Give an example.

Explanation

When a gene expresses itself in more than 2 allelic forms, then the alleles are called multiple alleles. E.g. The gene .I. controls the human blood group. It exist in 3 different alleleic forms i.e., `I^(A), I^(B) and I, and is responsible for the four human blood group viz, A, B, O and AB.