If two genes in a gene pair are for the same trait, they 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. For example, a gene for eye color could have different alleles: one for brown eyes and one for blue eyes.

* Gene pair: Two copies of the same gene, one from each parent.

So, when we talk about two genes in a gene pair being for the same trait, we are actually talking about two alleles of the same gene. These alleles can be the same (homozygous) or different (heterozygous), and they will determine the expression of that particular trait.