Editing Mutation (section)

=== Special classes ===
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* '''Conditional mutation''' is a mutation that has wild-type (or less severe) phenotype under certain "permissive" environmental conditions and a mutant phenotype under certain "restrictive" conditions. For example, a temperature-sensitive mutation can cause cell death at high temperature (restrictive condition), but might have no deleterious consequences at a lower temperature (permissive condition).<ref>{{Cite book|title=Molecular Biology of the Cell| vauthors = Alberts B |publisher=Garland Science|year=2014|isbn=9780815344322|edition=6|pages=487}}</ref> These mutations are non-autonomous, as their manifestation depends upon presence of certain conditions, as opposed to other mutations which appear autonomously.<ref name="Chadov-2015">{{cite journal | vauthors = Chadov BF, Fedorova NB, Chadova EV | title = Conditional mutations in Drosophila melanogaster: On the occasion of the 150th anniversary of G. Mendel's report in Brünn | journal = Mutation Research/Reviews in Mutation Research | volume = 765 | pages = 40–55 | date = 1 July 2015 | pmid = 26281767 | doi = 10.1016/j.mrrev.2015.06.001 | bibcode = 2015MRRMR.765...40C }}</ref> The permissive conditions may be [[Permissive temperature|temperature]],<ref name="Landis-2001">{{cite journal | vauthors = Landis G, Bhole D, Lu L, Tower J | title = High-frequency generation of conditional mutations affecting Drosophila melanogaster development and life span | journal = Genetics | volume = 158 | issue = 3 | pages = 1167–76 | date = July 2001 | doi = 10.1093/genetics/158.3.1167 | pmid = 11454765 | pmc = 1461716 | url = http://www.genetics.org/content/158/3/1167 | url-status = dead | access-date = 21 March 2017 | archive-url = https://web.archive.org/web/20170322014758/http://www.genetics.org/content/158/3/1167 | archive-date = 22 March 2017 }}</ref> certain chemicals,<ref name="Gierut-2014">{{cite journal | vauthors = Gierut JJ, Jacks TE, Haigis KM | title = Strategies to achieve conditional gene mutation in mice | journal = Cold Spring Harbor Protocols | volume = 2014 | issue = 4 | pages = 339–49 | date = April 2014 | pmid = 24692485 | pmc = 4142476 | doi = 10.1101/pdb.top069807 }}</ref> light<ref name="Gierut-2014" /> or mutations in other parts of the [[genome]].<ref name="Chadov-2015" /> ''[[In vivo]]'' mechanisms like transcriptional switches can create conditional mutations. For instance, association of Steroid Binding Domain can create a transcriptional switch that can change the expression of a gene based on the presence of a steroid ligand.<ref>{{cite journal | vauthors = Spencer DM | title = Creating conditional mutations in mammals | journal = Trends in Genetics | volume = 12 | issue = 5 | pages = 181–7 | date = May 1996 | pmid = 8984733 | doi = 10.1016/0168-9525(96)10013-5 }}</ref> Conditional mutations have applications in research as they allow control over gene expression. This is especially useful studying diseases in adults by allowing expression after a certain period of growth, thus eliminating the deleterious effect of gene expression seen during stages of development in model organisms.<ref name="Gierut-2014" /> DNA Recombinase systems like [[Cre-Lox recombination]] used in association with [[Promoter (genetics)|promoters]] that are activated under certain conditions can generate conditional mutations. Dual Recombinase technology can be used to induce multiple conditional mutations to study the diseases which manifest as a result of simultaneous mutations in multiple genes.<ref name="Gierut-2014" /> Certain [[intein]]s have been identified which splice only at certain permissive temperatures, leading to improper protein synthesis and thus, loss-of-function mutations at other temperatures.<ref>{{cite journal | vauthors = Tan G, Chen M, Foote C, Tan C | title = Temperature-sensitive mutations made easy: generating conditional mutations by using temperature-sensitive inteins that function within different temperature ranges | journal = Genetics | volume = 183 | issue = 1 | pages = 13–22 | date = September 2009 | pmid = 19596904 | pmc = 2746138 | doi = 10.1534/genetics.109.104794 }}</ref> Conditional mutations may also be used in genetic studies associated with ageing, as the expression can be changed after a certain time period in the organism's lifespan.<ref name="Landis-2001" />
* '''[[Replication timing quantitative trait loci]]''' affects DNA replication.