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
And once that mutation starts to spread, it’s protected by numbers since it won’t be wiped out if a few mosquitoes die by chance.
—Jacob A Tennessen, The Conversation, 26 Mar. 2026
The high number of mutations may be helping the variant evade protection from vaccination or from prior infections, which prompt the immune system to produce defensive antibodies.
—Tom Gavin, EverydayHealth.com, 25 Mar. 2026
Other mutations, random genetic changes that humans noticed and kept for planting the next year, helped along the way, notably those that multiplied the number of fruits on the stalk and fattened each seed.
—Literary Hub, 25 Mar. 2026
Think of it as a digital version of survival of the fittest for computer code, where generations of candidate solutions evolve and improve by applying operations like mutation and selection.
—Paul Sutter, Space.com, 22 Mar. 2026
See All Example Sentences for mutation
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Jacob A Tennessen, The Conversation, 26 Mar. 2026
The high number of mutations may be helping the variant evade protection from vaccination or from prior infections, which prompt the immune system to produce defensive antibodies.
—Tom Gavin, EverydayHealth.com, 25 Mar. 2026
Other mutations, random genetic changes that humans noticed and kept for planting the next year, helped along the way, notably those that multiplied the number of fruits on the stalk and fattened each seed.
—Literary Hub, 25 Mar. 2026
Think of it as a digital version of survival of the fittest for computer code, where generations of candidate solutions evolve and improve by applying operations like mutation and selection.
—Paul Sutter, Space.com, 22 Mar. 2026
See All Example Sentences for mutation
Cite this Entry
“Mutation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mutation. Accessed 29 Mar. 2026.
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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