gene /jēn/ [Gk, genein, to produce] , the biological unit of inheritance, consisting of a particular nucleotide sequence within a DNA sequence that occupies a precise locus on a chromosome and codes for a specific polypeptide chain. In diploid organisms, which include humans and other mammals, genes occur as paired alleles. Kinds include complementary gene, mutant gene, operator gene, pleiotropic gene, regulator gene, structural gene, supplementary gene. See also chromosome, cistron, deoxyribonucleic acid, operon.
