Definition

One of two or more alternative versions of a gene. A person inherits two alleles for each gene, one from the mother and one from the father. These two alleles may be the same or different. The alleles a person inherits help determine certain traits or characteristics, such as hair, skin, and eye color, height, and blood type. In some cases, one or both alleles may be mutated (changed from the original, normal version), which may cause disease.