What are the alleles of a gene?
The Diploid individuals have paired chromosomes. For instance in humans there are 23 pairs of chromosomes totaling 46 chromosomes. Every pair comprehends homologous chromosomes, one chromosome from the mother and another from the father, both of them containing information related to the production of the same proteins (with the exception of the sex chromosomes, which are partially heterologous). Consequently in the diploid individual it is said that each gene has two alleles, one in each chromosome of the homologous pair