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