Let's suppose our organism RP plants, the organisms that Gregor Mendel actually worked on. Now, this gene codes for some other protein for a third trait, and this codes for yet another protein for another trait. Now, notice that there are essentially homologous genes on the second homologous chromosome, we have a purple gene adjacent to this one, a green gene adjacent to this one, and so forth. And these genes, these pairs of genes, or homologous genes, are also known as alleles. And what alleles are they're basically genes found on the two different homologous chromosomes that code for proteins that express that same type of trait. So these two genes, the purple genes, are alleles because they code for proteins that express that same high trait.