<cell biology, molecular biology> Originally defined as the physical unit of heredity, it is probably best defined as the unit of inheritance that occupies a specific locus on a chromosome, the existence of which can be confirmed by the occurrence of different allelic forms.

Genes are formed from DNA, carried on the chromosomes and are responsible for the inherited characteristics that distinguish one individual from another. Each human individual has an estimated 100,000 separate genes.

Given the occurrence of split genes, it might be redefined as the set of DNA sequences (exons) that are required to produce a single polypeptide.

(09 Oct 1997)