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.
Brain blood flow improved among participants carrying APOE4, but the same benefit was not observed in those without the gene variant.
From Science Daily ● Nov. 6, 2026
Without knowing which gene produced the enzyme, scientists could not easily manipulate it in experiments or determine how problems with its activity might contribute to disease.
From Science Daily ● Nov. 5, 2026
"I said, 'Let's cut straight to it.' They said, 'We're really sorry, it's not good news, and you have inherited the gene.'"
From BBC ● Nov. 5, 2026
If she had the gene, her expected age of decline would be 46 to 48, he said.
From BBC ● Nov. 5, 2026
What was the chemical and physical nature of the gene?
From "The Gene" by Siddhartha Mukherjee
Gene therapy is already being used to treat certain serious illnesses.
From Science Daily ● Nov. 4, 2026
As Jean-Luc Picard, the captain who inherited the helm of USS Enterprise from William Shatner’s James T. Kirk, Stewart embodied franchise founder Gene Roddenberry’s humanist outlook.
From Salon ● Oct. 30, 2026
But Star Trek creator Gene Roddenberry's studio also publicised the role as a response to criticism in Pravda, the main newspaper of the Soviet Communist Party, about the lack of a Russian character.
From BBC ● Oct. 26, 2026
Netflix’s newest reality competition series is based on ‘Willy Wonka and the Chocolate Factory,’ and among its detriments is using the AI-generated voice of the late Gene Wilder.
From Los Angeles Times ● Oct. 21, 2026
When we came out, Bobby Gene was carrying the gunnysack, which could easily have been Susie all wrapped up in a blanket or something.
From "The Season of Styx Malone" by Kekla Magoon
Coupled with abundant haplotype diversity, tetraploid potato may therefore contain thousands of -gene analogues.
From Nature ● Jul. 13, 2011
As somebody that grew up in British Columbia around the Haida and the different tribes that come from there, it’s steeped in my genes to recognize that.
From Los Angeles Times ● Nov. 5, 2026
The team then refined the results by concentrating on genes associated with proteins released outside cells, a common characteristic of hormones.
From Science Daily ● Nov. 4, 2026
I adorn myself so loudly in my nationality that the first thing people see isn’t my father’s dominant Swiss genes, but a declaration of my true birthright.
From Los Angeles Times ● Nov. 4, 2026
Published in Science Advances, the findings provide a new picture of how prehistoric Europeans interacted, exchanged genes, and maintained populations through thousands of years of dramatic environmental change.
From Science Daily ● Nov. 2, 2026
If Dobzhansky had capriciously trimmed the wings of all the flies in one box, he would have affected their phenotypes—the shape of their wings—without ever touching their genes.
From "The Gene" by Siddhartha Mukherjee
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