mutation
noun
mu·ta·tion
myü-ˈtā-shən 
1
: a significant and basic alteration : change
2
: umlaut
3
a
: a relatively permanent change in hereditary material that involves either a change in chromosome structure or number (as in translocation, deletion, duplication, or polyploidy) or a change in the nucleotide sequence of a gene's codons (as in frameshift or missense errors) and that occurs either in germ cells or in somatic cells but with only those in germ cells being capable of perpetuation by sexual reproduction
Mutations known to cause disease have been identified in approximately 1000 genes.—
Alan E. Guttmacher and Francis S. Collins
Alan E. Guttmacher and Francis S. Collins
also
: the process of producing a mutation
Microorganisms have been used extensively to study mutation … —George A. Wistreich et al.
George A. Wistreich et al.
b
: an individual, strain, or trait resulting from mutation
The worst E. coli bacterium, E. coli 0157:H, a mutation discovered in 1982 that has at least sixty-two subtypes, causes hemorrhagic colitis …—Wayne Biddle
Wayne Biddle
mutationally
adverb
Examples of mutation in a Sentence
The cat's short tail is the result of mutation.
The condition is caused by a genetic mutation.
The building is a mutation of the original design.
Recent Examples on the Web
Genetic testing helps identify underlying mutations or abnormalities in genes.
—Anna Giorgi, Verywell Health, 29 July 2025
The algae and the slug may have managed some kind of gene transfer, and over time, produced a new way of living, thanks not to slow, stepwise evolution—the random mutation within a body—but by the wholesale transfer of a piece of code.
—Zoë Schlanger, The Atlantic, 23 July 2025
But the study builds on existing evidence that over time, mutations in these pathogens helped strengthen the immune systems of the nomads that were among the first to get sick, while more stagnant farmers and hunter-gatherers succumbed to the new diseases.
—Christian Thorsberg, Smithsonian Magazine, 23 July 2025
In contrast, people who smoke tend to accumulate many mutations over time that can eventually lead to cancer.
—Nina Agrawal, New York Times, 22 July 2025
See All Example Sentences for mutation
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Anna Giorgi, Verywell Health, 29 July 2025
The algae and the slug may have managed some kind of gene transfer, and over time, produced a new way of living, thanks not to slow, stepwise evolution—the random mutation within a body—but by the wholesale transfer of a piece of code.
—Zoë Schlanger, The Atlantic, 23 July 2025
But the study builds on existing evidence that over time, mutations in these pathogens helped strengthen the immune systems of the nomads that were among the first to get sick, while more stagnant farmers and hunter-gatherers succumbed to the new diseases.
—Christian Thorsberg, Smithsonian Magazine, 23 July 2025
In contrast, people who smoke tend to accumulate many mutations over time that can eventually lead to cancer.
—Nina Agrawal, New York Times, 22 July 2025
See All Example Sentences for mutation
Cite this Entry
“Mutation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mutation. Accessed 2 Aug. 2025.
Copy CitationKids Definition
mutation
noun
mu·ta·tion
myü-ˈtā-shən
1
: a basic and important change
2
a
: a permanent change in hereditary material involving either a change in the position of the genes on the chromosomes or a basic change in the chemical structure of a gene
also
: the process of producing a mutation
b
: an individual, strain, or trait resulting from mutation
Medical Definition
mutation
noun
mu·ta·tion
myü-ˈtā-shən
1
: a relatively permanent change in hereditary material that involves either a change in chromosome structure or number (as in translocation, deletion, duplication, or polyploidy) or a change in the nucleotide sequence of a gene's codons (as in frameshift or missense errors) and occurs either in germ cells or in somatic cells but with only those in germ cells being capable of perpetuation by sexual reproduction
also
: the process of producing a mutation
2
: an individual, strain, or trait resulting from mutation
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