Metraipolis › archive › dc_cd83dc401eda

Synonymous substitution — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Synonymous_substitution
License (as archived): CC-BY-SA-4.0
Archived: 2026-10-08T00:24:06.954Z
SHA-256 of the archived text: c57995a377fe16b058605eafa93da542f53900efe5bcbbac98fd6fed02230cbe
Stable URL of this page: https://metraipolis.com/documento/dc_cd83dc401eda

How to cite

Synonymous substitution — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Synonymous_substitution (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_cd83dc401eda (Metraipolis archive dc_cd83dc401eda, sha256 c57995a377fe16b058605eafa93da542f53900efe5bcbbac98fd6fed02230cbe)

BibTeX

@misc{dccd83dc401eda,
  title = {Synonymous substitution — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Synonymous_substitution},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_cd83dc401eda; sha256 c57995a377fe16b058605eafa93da542f53900efe5bcbbac98fd6fed02230cbe},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Synonymous_substitution. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

A synonymous substitution (often called a silent substitution though they are not always silent) is the evolutionary substitution of one base for another in an exon of a gene coding for a protein, such that the produced amino acid sequence is not modified. This is possible because the genetic code is "degenerate", meaning that some amino acids are coded for by more than one three-base-pair codon; since some of the codons for a given amino acid differ by just one base pair from others coding for the same amino acid, a mutation that replaces the "normal" base by one of the alternatives will result in incorporation of the same amino acid into the growing polypeptide chain when the gene is translated. Synonymous substitutions and mutations affecting noncoding DNA are often considered silent mutations; however, it is not always the case that the mutation is silent. Since there are 22 codes for 64 codons, roughly we should expect a random substitution to be synonymous with probability about 22/64 = 34%. The actual value is around 20%. A synonymous mutation can affect transcription, splicing, mRNA transport, and translation, any of which could alter the resulting phenotype, rendering the synonymous mutation non-silent. The substrate specificity of the tRNA to the rare codon can affect the timing of translation, and in turn the co-translational folding of the protein. This is reflected in the codon usage bias that is observed in many species. A nonsynonymous substitution results in a change in amino acid that may be arbitrarily further classified as conservative (a change to an amino acid with similar physiochemical properties), semi-conservative (e.g. negatively to positively charged amino acid), or radical (vastly different amino acid).

Tema degli esploratori: scienze della vita e salute (deposito sistematico; categoria «Molecular biology»).
Fonte: Wikipedia in inglese, voce «Synonymous substitution» — https://en.wikipedia.org/wiki/Synonymous_substitution
Wikidata Q7662597 (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q7662597
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Synonymous_substitution?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1322492776, consultata il 2026-10-08T00:01:59.013Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: ba64819fa573c34803d658ba0d636de01390893ba6df14e9c0554724a405c910