gene 
(jēn)
(jēn)n.
A hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and is transcribed into an RNA molecule that may function directly or be translated into an amino acid chain. Genes undergo mutation when their DNA sequences change.
[German Gen, from gen-, begetting, in Greek words (such as genos, race, offspring); see genə- in the Appendix of Indo-European roots.]