1. A unit of
DNA that carries information for the biosynthesis of a specific product (in the cell). 2. Ultimate unit by which inheritable characteristics are transmitted to succeeding generations in all living organisms. Genes are contained by, and arranged along the length of, the chromosome. The gene is composed of deoxyribonucleic acid (
DNA). Each chromosome of each species has a definite number and arrangement of genes, which govern both the structure and metabolic functions of the cells and thus of the entire organism. They provide information for the
synthesis of enzymes and other
proteins and specify when these substances are to be made. Alteration of either gene number or arrangement can result in
mutation (a change in the inheritable traits). See also
DNA.