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.
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Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Players will be tested just once in their lifetime and only a negative result, showing no presence of the gene, will permit them to compete on the Tour.
From BBC ● Jul. 20, 2026
NR4A1 is part of a group of nuclear receptors that help control gene activity when the body is exposed to stress or tissue damage.
From Science Daily ● Jul. 19, 2026
It’s also a headwind for Alnylam, whose Amvuttra treatment will remain the only gene silencer for ATTR-CM, the analysts write, although long-term questions remain for the company’s next-generation silencer.
From The Wall Street Journal ● Jul. 10, 2026
When it comes to fear of heights, Maddi Haferling was born with the opposite gene — loving heights.
From Los Angeles Times ● Jul. 8, 2026
The atom, the byte, and the gene provide fundamentally new scientific and technological understandings of their respective systems.
From "The Gene" by Siddhartha Mukherjee
These days, even buying “a starter home just seems so daunting,” Gene White, a 27-year-old who works in communications, told MarketWatch.
From MarketWatch ● Jul. 9, 2026
Netflix is so psyched about generative software that it’s spent the year acquiring an A.I. production studio, launching a different studio for A.I.-animated shorts, and re-creating Gene Wilder’s voice for a Willy Wonka–themed game show.
From Slate ● Jul. 2, 2026
“Hi Gene, what do you think about SpaceX’s valuation?”
From Barron's ● Jun. 18, 2026
Gene Shalit, the fast-talking funnyman who reviewed films, plays and books for NBC’s “Today” show has died.
From Los Angeles Times ● Jun. 13, 2026
The Boston editor called Gene Roberts, his boss in New York, for guidance.
From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin
Coupled with abundant haplotype diversity, tetraploid potato may therefore contain thousands of -gene analogues.
From Nature ● Jul. 13, 2011
These tools estimate biological age by measuring DNA methylation, a pattern of chemical tags that influences how genes are switched on or off without changing the DNA sequence itself.
From Science Daily ● Jul. 14, 2026
About 20% of aortic dissections are thought to be the result of genes.
From MarketWatch ● Jul. 13, 2026
In a separate mouse model of Parkinson's disease, removing the genes for either protein also reduced symptom progression and lowered the risk of death.
From Science Daily ● Jul. 12, 2026
For all their power, genes do not speak of past loves.
From Science Daily ● Jul. 7, 2026
First, genes had to be made of matter.
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.
