An individual with two different alleles for a gene is called heterozygous.

Here's a breakdown:

* Alleles: Different versions of a gene.

* Heterozygous: Having two different alleles for a particular gene.

* Homozygous: Having two identical alleles for a particular gene.

For example, if a gene for eye color has two alleles, "B" for brown eyes and "b" for blue eyes, an individual with the genotype "Bb" would be heterozygous for eye color. They would have one allele for brown eyes and one allele for blue eyes.