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.

---

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

---

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

---

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”; mutate, -ion

Example Sentences

To get a more accurate genetic indicator of cancer risk, my mother encouraged me to get my DNA tested for the BRCA1 gene mutation.

From Los Angeles Times • Mar. 17, 2026

A protective mutation identified in South Asia may point to mechanisms driving cardiovascular or metabolic disease worldwide.

From The Wall Street Journal • Mar. 12, 2026

"What makes this study particularly valuable is that we used human neurons carrying an actual disease-causing mutation," Samelson said.

From Science Daily • Mar. 3, 2026

Using advanced genome-editing tools and a fluorescent readout, the team measured how strongly each mutation activated the β-catenin pathway.

From Science Daily • Feb. 5, 2026

Possibly he was imagining what it would be like to discover a whole new population of carriers of the 5-alpha-reductase mutation.

From "Middlesex: A Novel" by Jeffrey Eugenides

Related Words

• alteration
• anomaly
• variation