Let's consider the trait of eye color. Here's an example of different forms a gene might have for this trait:

* Gene: The gene responsible for eye color is called OCA2.

* Alleles (different forms of the gene):

* Brown allele: This allele produces a protein that creates a lot of melanin (the pigment that gives color to our eyes, hair, and skin).

* Blue allele: This allele produces a protein that creates less melanin, resulting in blue eyes.

So, in this case, the brown allele and the blue allele are different forms of the same gene (OCA2) that lead to different eye colors.

Here's a simplified example:

* Parent 1: Has one brown allele (B) and one blue allele (b) for eye color.

* Parent 2: Has two blue alleles (bb) for eye color.

Possible offspring:

* BB: Brown eyes

* Bb: Brown eyes (because the brown allele is dominant)

* bb: Blue eyes

This example illustrates how different alleles of the same gene can lead to variations in a trait.