A segment of DNA, occupying a specific place on a chromosome, that is the basic unit of heredity. Genes act by directing the production of RNA, which determines the synthesis of proteins that make up living matter and are the catalysts of all cellular processes. The proteins that are determined by genetic DNA result in specific physical traits, such as the shape of a plant leaf, the coloration of an animal's coat, or the texture of a person's hair. Different forms of genes, called alleles, determine how these traits are expressed in a given individual. Humans are thought to have 20,000 to 25,000 genes; bacteria have between 500 and 6,000.
What is a gene? A gene is a sequence of nucleotides along a strand of DNA that a cell nucleus uses to produce proteins. Genes determine the specific traits of an organism. DNA (deoxyribonucleic acid) is a large molecule that is shaped like a double helix sometimes described as a twisty ladder. The rungs of the ladder are made of molecules called nucleotides. These rungs, or bases, are arranged in a specific order that creates a set of instructions, which is known as a gene. When the body needs to do something or build something, it often requires a protein. Genes are the instructions that the cells read for how to build proteins. Proteins have very specific jobs, so scientists name genes based on what job their linked proteins are designed to do. For example, hair proteins come from hair genes, while eye proteins come from eye genes. Every living organism has genes. Animals, plants, fungi, bacteria, and even the humble amoeba all have genes. The more closely related two organisms are, the more similar their genes will be. For example a dog and a wolf, which are from the same genus, will have similar genes, while a dog and a human, which are not part of the same genus, will have much different genes from each other.
First recorded in 1911; from German Gen (1909), apparently abstracted from -gen -gen ( def. ); introduced by Danish geneticist Wilhelm L. Johannsen (1857–1927)
Microscopic, yet powerful, a gene is segment of DNA, the molecule that stores the code for building living bodies. A gene is a single unit of genetic information, stored on twisting strands in every cell of every living being. In sexual reproduction, the parents' genes mix together to make the child. Although people would like to think that genes code for discrete traits, like friendliness or mathematical genius, that's not the case. Genes control the color of your eyes and the shape of your toes, not your weird personality.
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Regeneron’s gene therapy to cure a rare form of deafness treats so few children that the company decided to make the treatment free.
From The Wall Street Journal ● Aug. 10, 2026
Her dad Charlie felt earlier detection could have given her a chance of walking, as he had seen "a big difference" since she had a one-off gene therapy infusion in Bristol.
From BBC ● Aug. 9, 2026
Changes in gene activity may contribute to neck and back pain by damaging the discs that act as the spine's natural shock absorbers, according to new research.
From Science Daily ● Aug. 6, 2026
He spent about 10 years looking for the gene behind the condition and ultimately discovered that people with narcolepsy who experience sudden muscle weakness were missing the chemical orexin.
From The Wall Street Journal ● Aug. 6, 2026
Was one gene physically or chemically linked to another?
From "The Gene" by Siddhartha Mukherjee
That pool’s 10-meter platform, originally constructed with a donation from the late televangelist Gene Scott, will be torn down and replaced.
From Los Angeles Times ● Aug. 1, 2026
He said that the franchise's longevity was due to "all the people like you and your parents and your grandparents, because of their intelligence and their sensitivity and their vision" in supporting Gene Roddenberry's concept.
From Barron's ● Jul. 26, 2026
While Mr. Richman’s vocals retained punk’s nasal, monochromatic tone, his songs were dorky and witty, channeling Buddy Holly, Gene Vincent and Freddie and the Dreamers.
From The Wall Street Journal ● Jul. 22, 2026
The move is likely a case of “buy on the rumor, sell on the news,” according to Gene Munster, managing partner at Deepwater Asset Management.
From MarketWatch ● Jul. 2, 2026
We all turn, and in step Principal Espinosa and Gene.
From "Popcorn" by Rob Harrell
Coupled with abundant haplotype diversity, tetraploid potato may therefore contain thousands of -gene analogues.
From Nature ● Jul. 13, 2011
Ms. Gray, then 34, was the first person to receive treatment based on the Crispr method of editing genes.
From The Wall Street Journal ● Aug. 10, 2026
Researchers have identified genes in Tibetan dogs that allow them to function in oxygen-poor conditions that would challenge breeds from lower elevations.
From Science Daily ● Aug. 10, 2026
Small RNA molecules help control how genes are expressed and can influence the activity of cells throughout the body.
From Science Daily ● Aug. 9, 2026
Cohen found MOTS-c by combing through the 97% of human DNA that doesn’t encode for genes.
From Los Angeles Times ● Aug. 6, 2026
Genes reside on chromosomes—long, filamentous structures buried within cells that contain tens of thousands of genes linked together in chains.*
From "The Gene" by Siddhartha Mukherjee
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
