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From Biology-Online Dictionary | Biology-Online Dictionary
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noun, plural: mutations

(genetics) A permanent, heritable change in the nucleotide sequence in a gene or a chromosome; the process in which such a change occurs in a gene or in a chromosome

(genetics) A mutant, or an individual exhibiting such a change

(general) A change in or the process of changing, e.g. nature, form or quality


Mutation is a change in the nucleotide sequence of a gene or a chromosome. It may be classified into various ways. One of these classifications involves classifying mutations based on the effect on structure: (1) small-scale mutations and (2) large scale mutations. Small-scale mutations affect one or few nucleotides of a gene. These are further classified into substitution mutations (further typified into silent mutations, missense mutations, and nonsense mutations), insertions, and deletions. Large-scale mutations involve a change in the chromosome). They are classified further into amplifications (or gene duplications), deletions of large chromosomal regions, and chromosomal inversions.

Mutations may also be classified based on the impact on protein sequence: (1) frameshift mutations, (2) nonsense mutations, (3) missense mutations, (4) neutral mutations, and (5) silent mutations.

Mutations may arise from faulty deletions, insertions, or exchanges of nucleotides in the genetic material, as caused by exposure to ultraviolet or ionizing radiation, chemical mutagens, viruses, and other mutagens. Such a change may result in the creation of a new character or trait.

Word origin: mutatio, from mutare ("to change an organism that has characteristics resulting from chromosomal alteration")

See also:

Related terms:

Related forms:

  • mutant (noun)
  • mutate (verb, change in the genetic material, e.g. DNA, inside the cell)

User Contributions / Comments:

  • Mutation is essential to evolution. They introduce new traits in a population,change allele frequencies and include changes in the DNA sequences.
  • Mutations introduce new traits in a population, change allele frequencies and include changes in the DNA sequences.