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.
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
Most types are caused by an altered gene being passed to a child by their parents and blood tests can be used to confirm a diagnosis.
From BBC ● Aug. 9, 2026
These combined methods allowed the researchers to identify changes in immune cell identity and origin that would have remained hidden if they had examined gene activity alone.
From Science Daily ● Aug. 7, 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
A chemist seeking to understand the gene has no more opportune moment to capture the chemical nature of the gene.
From "The Gene" by Siddhartha Mukherjee
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
Billy Gene Mills was elected to the Los Angeles City Council in 1963 and served until 1974.
From Los Angeles Times ● Jul. 16, 2026
Gene Lanzoni rose up through the ranks in the insurance industry while taking care of his wife, who had breast cancer, as well as his aging parents and in-laws during different periods of his career.
From MarketWatch ● Jul. 7, 2026
One time he was playing at a private club in New York where on the neighbouring court Hollywood actors Gene Wilder and Sidney Poitier were filming a movie.
From BBC ● Jul. 7, 2026
“No. Unrelated. I bled on my gym shirt. Gene ruined the new shirt.”
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
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
Genetic family tree studies show that such transfers have occurred, but scientists have generally assumed that jumping genes traveled as passengers inside plasmids or viruses.
From Science Daily ● Aug. 5, 2026
About one in seven women develop breast cancer in their lifetime, yet only 5-10% of cases are linked to inherited genes.
From BBC ● Aug. 4, 2026
While my family’s history of mental illness was cutting through my consciousness like a red line, my scientific work as a cancer biologist was also converging on the normalcy and abnormalcy of genes.
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.
