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
Today, many women are offered drugs designed to target specific cancer cell mutations, sparing them unnecessary toxicity.
—Lauryn Higgins, Flow Space, 21 Oct. 2025
All of the children in the trial have a rare mutation in the instructions for making a protein called otoferlin, which helps sensory cells in the cochlea communicate with the brain.
—Lisa Jarvis, Twin Cities, 19 Oct. 2025
This part of the study provided the first direct functional proof that mutations within the phage genome can permanently silence its ability to reactivate.
—New Atlas, 16 Oct. 2025
For example, mutations in the CNTNAP2 gene, which plays a role in the development and function of the nervous system, have been linked to a predisposition of autism, particularly among some Amish children.
—Mary Kekatos, ABC News, 14 Oct. 2025
See All Example Sentences for mutation
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Lauryn Higgins, Flow Space, 21 Oct. 2025
All of the children in the trial have a rare mutation in the instructions for making a protein called otoferlin, which helps sensory cells in the cochlea communicate with the brain.
—Lisa Jarvis, Twin Cities, 19 Oct. 2025
This part of the study provided the first direct functional proof that mutations within the phage genome can permanently silence its ability to reactivate.
—New Atlas, 16 Oct. 2025
For example, mutations in the CNTNAP2 gene, which plays a role in the development and function of the nervous system, have been linked to a predisposition of autism, particularly among some Amish children.
—Mary Kekatos, ABC News, 14 Oct. 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 30 Oct. 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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