Editing Mutation rate (section)

{{short description|Rate at which mutations occur during some unit of time}}
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[[File:Recent estimates of the human genome-wide mutation rate.png|thumb|Recently reported estimates of the human genome-wide mutation rate. The human [[germline]] mutation rate is approximately 0.5×10<sup>−9</sup> per [[basepair]] per year.<ref name="Scally2016">{{cite journal | vauthors = Scally A | title = The mutation rate in human evolution and demographic inference | journal = Current Opinion in Genetics & Development | volume = 41 | pages = 36–43 | date = December 2016 | pmid = 27589081 | doi = 10.1016/j.gde.2016.07.008 | url = https://www.repository.cam.ac.uk/handle/1810/257350 | access-date = 2020-09-08 | url-status = live | archive-url = https://web.archive.org/web/20210102024301/https://www.repository.cam.ac.uk/handle/1810/257350 | archive-date = 2021-01-02 }}</ref>]]
In [[genetics]], the '''mutation rate''' is the frequency of new [[mutations]] in a single [[gene]], [[nucleotide sequence]], or organism over time.<ref>{{cite journal | vauthors = Crow JF | title = The high spontaneous mutation rate: is it a health risk? | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 94 | issue = 16 | pages = 8380–8386 | date = August 1997 | pmid = 9237985 | pmc = 33757 | doi = 10.1073/pnas.94.16.8380 | doi-access = free | bibcode = 1997PNAS...94.8380C }}</ref> Mutation rates are not constant and are not limited to a single type of mutation; there are many different types of mutations. Mutation rates are given for specific classes of mutations. [[Point mutations]] are a class of mutations which are changes to a single base. [[Missense mutation|Missense]], [[Nonsense mutation|nonsense]], and [[Synonymous substitution|synonymous mutations]] are three subtypes of point mutations. The rate of these types of substitutions can be further subdivided into a mutation spectrum which describes the influence of the genetic context on the mutation rate.<ref>{{cite journal | vauthors = Pope CF, O'Sullivan DM, McHugh TD, Gillespie SH | title = A practical guide to measuring mutation rates in antibiotic resistance | journal = Antimicrobial Agents and Chemotherapy | volume = 52 | issue = 4 | pages = 1209–1214 | date = April 2008 | pmid = 18250188 | pmc = 2292516 | doi = 10.1128/AAC.01152-07 }}</ref>

There are several natural units of time for each of these rates, with rates being characterized either as mutations per base pair per cell division, per gene per generation, or per genome per generation. The mutation rate of an organism is an evolved characteristic and is strongly influenced by the genetics of each organism, in addition to strong influence from the environment. The upper and lower limits to which mutation rates can evolve is the subject of ongoing investigation. However, the mutation rate does vary over the [[genome]].<ref>{{cite journal | vauthors = Moxon ER, Rainey PB, Nowak MA, Lenski RE | title = Adaptive evolution of highly mutable loci in pathogenic bacteria | journal = Current Biology | volume = 4 | issue = 1 | pages = 24–33 | date = January 1994 | pmid = 7922307 | doi = 10.1016/s0960-9822(00)00005-1 | bibcode = 1994CBio....4...24M }}</ref> 

When the mutation rate in humans increases certain health risks can occur, for example, [[cancer]] and other hereditary diseases. Having knowledge of mutation rates is vital to understanding the future of cancers and many hereditary diseases.<ref>{{cite journal | vauthors = Tomlinson IP, Novelli MR, Bodmer WF | title = The mutation rate and cancer | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 93 | issue = 25 | pages = 14800–14803 | date = December 1996 | pmid = 8962135 | pmc = 26216 | doi = 10.1073/pnas.93.25.14800 | doi-access = free | bibcode = 1996PNAS...9314800T }}</ref>