One of a set of alternate forms of a gene. An example is the different alleles of eye color. Each of the different forms of the gene code for eye color, only each codes for a different color i.e. blue, brown, green.

Any one of a series of two or more different genes that may occupy the same locus on a specific chromosome. As autosomal chromosomes are paired each autosomal gene is represented twice in normal somatic cells. If the same a. occupies this a. If the a.'s are different, the individual or cell is heterozygous for both a.'s.

genes that control the same inherited trait (such as height or eye color); they are located at the same position (locus) on homologous chromosomes

any of the alternative forms of a gene at a given locus