Multiple alleles are characterised by

Options

A. More than two alternate forms of a gene found at same locus
B. More than two alternate forms of a gene found at different loci
C. Occurrence of one gene in two chromosomes
D. None of the above

Answer

### Step-by-Step Solution:

1. **Understanding Alleles**:
- Alleles are defined as the different forms of a gene that can exist at a specific locus on a chromosome. Each individual inherits two alleles for each gene, one from each parent.

2. **Definition of Multiple Alleles**:
- Multiple alleles refer to the presence of more than two alternative forms of a gene at a given locus. This means that instead of just having two alleles (like dominant and recessive), there are three or more variations.

3. **Characteristics of Multiple Alleles**:
- The key characteristic of multiple alleles is that they occupy the same locus on a chromosome. This means that while there can be several different alleles, they all correspond to the same gene location.

4. **Examples of Multiple Alleles**:
- A classic example of multiple alleles is the ABO blood group system in humans, where the alleles I^A, I^B, and i exist at the same locus, leading to four possible blood types: A, B, AB, and O.

5. **Conclusion**:
- Therefore, multiple alleles are characterized by the presence of more than two alternative forms of a gene found at the same locus on a chromosome.

### Answer:
Multiple alleles are characterized by the presence of more than two alternative forms of a gene at the same locus.

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