Jeni (kwa Kiingereza "gene", kutoka Kigiriki γόνος, gonos, yaani uzao) ni mahali pa DNA. DNA ni mkusanyiko wa taarifa za kemikali ambazo hubeba maelekezo kwa ajili ya kutengeneza protini kwenye seli. Kila jeni ina seti moja ya maelekezo. Maelekezo haya kawaida msimbo ya protini fulani. Wanadamu wana jeni takribani 27,000. Nusu ya jeni ya mtu huja kutoka kwa mama. Nusu nyingine kuja kutoka kwa baba. (2013) Molecular Biology of the Gene, 7th, Benjamin Cummings. ISBN 978-0-321-90537-6.  Dawkins, Richard (1990). The Selfish Gene. Oxford University Press. ISBN 0-19-286092-5.  Google Book Search; first published 1976. Ridley, Matt (1999). Genome: The Autobiography of a Species in 23 Chapters. Fourth Estate. ISBN 0-00-763573-7.  Brown, T (2002). Genomes, 2nd, New York: Wiley-Liss. ISBN 0-471-25046-5.  Comparative Toxicogenomics Database DNA From The Beginning – a primer on genes and DNA Entrez Gene – a searchable database of genes IDconverter – converts gene IDs between public databases iHOP – Information Hyperlinked over Proteins Archived 17 Oktoba 2005 at the Wayback Machine. TranscriptomeBrowser – Gene expression profile analysis Archived 20 Julai 2011 at the Wayback Machine.