The different forms of a trait that a gene may have are called alleles.

Here's a breakdown:

* Gene: A segment of DNA that codes for a specific trait.

* Allele: A specific version of a gene.

* Trait: A characteristic or feature of an organism.

For example, the gene for eye color has different alleles, such as the allele for blue eyes or the allele for brown eyes. Each individual inherits two alleles for each gene, one from each parent. The combination of alleles determines the individual's trait.