Question

Describe allele and multiple allele.

Hint:

Recall the ABO blood group as the standard multiple-allele example.

Answer 1

Step 1: Allele:
An allele is one of two or more alternative forms of a gene that occupy the same locus on homologous chromosomes and govern the same trait; e.g., in the pea plant, the gene for stem height has a tall allele (T) and a dwarf allele (t).

Step 2: Multiple Allele:
When a single gene exists in more than two allelic forms within a population (though any one diploid individual carries only two of them), it is called multiple alleles; the classic example is the human ABO blood group, controlled by gene I with three alleles — Iᴬ, Iᴮ, and i.