Editing Mutation (section)

=== Randomness of mutations ===
There is a widespread assumption that mutations are (entirely) "random" with respect to their consequences (in terms of probability). This was shown to be wrong as mutation frequency can vary across regions of the genome, with such [[DNA repair]]- and mutation-biases being associated with various factors. For instance, Monroe and colleagues demonstrated that—in the studied plant (''Arabidopsis thaliana'')—more important genes mutate less frequently than less important ones. They demonstrated that mutation is "non-random in a way that benefits the plant".<ref>{{cite news |title=Study challenges evolutionary theory that DNA mutations are random |url=https://phys.org/news/2022-01-evolutionary-theory-dna-mutations-random.html |access-date=12 February 2022 |work=[[U.C. Davis]] |language=en}}</ref><ref>{{cite journal | vauthors = Monroe JG, Srikant T, Carbonell-Bejerano P, Becker C, Lensink M, Exposito-Alonso M, Klein M, Hildebrandt J, Neumann M, Kliebenstein D, Weng ML, Imbert E, Ågren J, Rutter MT, Fenster CB, Weigel D | display-authors = 6 | title = Mutation bias reflects natural selection in Arabidopsis thaliana | journal = Nature | volume = 602 | issue = 7895 | pages = 101–105 | date = February 2022 | pmid = 35022609 | pmc = 8810380 | doi = 10.1038/s41586-021-04269-6 | bibcode = 2022Natur.602..101M }}</ref> Additionally, previous experiments typically used to demonstrate mutations being random with respect to fitness (such as the [[Fluctuation Test]] and [[Replica plating]]) have been shown to only support the weaker claim that those mutations are random with respect to external selective constraints, not fitness as a whole.<ref>{{cite journal |doi=10.1007/s10441-023-09464-8 |author=Bartlett, J. |title=Random with Respect to Fitness or External Selection? An Important but Often Overlooked Distinction |journal=Acta Biotheoretica |volume=71 |issue=2 |date=2023 |page=12 |pmid=36933070 |s2cid=257585761 }}</ref>