mutation

American  

[myoo-tey-shuhn] / myuˈteɪ ʃən /

noun

1. Biology.

   1. Also called break.  a sudden departure from the parent type in one or more heritable characteristics, caused by a change in a gene or a chromosome.

   2. Also called sport.  an individual, species, or the like, resulting from such a departure.

2. the act or process of changing.

3. a change or alteration, as in form or nature.

4. Phonetics. umlaut.

5. Linguistics. (in Celtic languages) syntactically determined morphophonemic phenomena that affect initial sounds of words.

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mutation British  

/ mjuːˈteɪʃən /

noun

1. the act or process of mutating; change; alteration

2. a change or alteration

3. a change in the chromosomes or genes of a cell. When this change occurs in the gametes the structure and development of the resultant offspring may be affected See also inversion

4. another word for mutant

5. a physical characteristic of an individual resulting from this type of chromosomal change

6. phonetics

   1. (in Germanic languages) another name for umlaut

   2. (in Celtic languages) a phonetic change in certain initial consonants caused by a preceding word

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mutation Scientific  

/ myo̅o̅-tā′shən /

1. A change in the structure of the genes or chromosomes of an organism. Mutations occurring in the reproductive cells, such as an egg or sperm, can be passed from one generation to the next. Most mutations occur in junk DNA and have no discernible effects on the survivability of an organism. Of the remaining mutations, the majority have harmful effects, while a minority can increase an organism's ability to survive. A mutation that benefits a species may evolve by means of natural selection into a trait shared by some or all members of the species.

2. See Note at sickle cell anemia

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Other Word Forms

• mutational
  adjective
• mutationally
  adverb
• nonmutational
  adjective
• nonmutationally
  adverb
• unmutational
  adjective

Etymology

Origin of mutation

First recorded in 1325–75; Middle English mutacio(u)n, from Latin mūtātion- (stem of mūtātiō ) “a changing”; see mutate, -ion

Explanation

A mutation is a genetic change that causes new and different characteristics, like the mutation on the dog's DNA that makes its tail shorter than its ancestors' tails. Mutation comes from the Latin word mutationem meaning "a changing." You might recognize this root in related words like mutate, mutable, and mutant. We often think of mutations as changes in an animal's genetic structure, but there are other kinds of mutations. For example, if an architect designs an award-winning building, her later designs that are similar might be called mutations of that one.

Example Sentences

Scientists have rejected the idea that a recent mutation made the Andes virus transmissible between humans.

From Barron's • May 15, 2026

It essentially recognizes that if you’re in your 80s, pancreatic cancer might be environmental, but if you’re in your 50s, as I was, it’s almost certainly a genetic mutation.

From The Wall Street Journal • May 7, 2026

Bourla teased upcoming updates for Braftovi, a treatment targeting a specific mutation found in about 10% of metastatic colon cancer cases.

From Barron's • May 5, 2026

How could such a structure possibly have evolved its way into existence one random mutation at a time?

From The Wall Street Journal • Apr. 16, 2026

Koyré had a vast influence in America, and his Bachelardian conception of an intellectual mutation was adopted by Thomas Kuhn in The Structure of Scientific Revolutions.

From "The Invention of Science" by David Wootton

Related Words

• alteration
• anomaly
• variation