What is Point mutation?
[[File:Point mutations-en.png|thumb|500px|Illustration of three types of point mutations.]] A '''point mutation''' is a ''single base substitution''.<ref>{{cite web |url=http://utminers.utep.edu/rwebb/html/what_is_a_mutation_.html |title=What is a mutation? |publisher=University of Texas, El Passo |accessdate=January 23, 2017 |archive-date=December 3, 2016 |archive-url=https://web.archive.org/web/20161203211104/http://utminers.utep.edu/rwebb/html/what_is_a_mutation_.html |url-status=dead }}</ref> It is the smallest type of [[mutation]] possible. In a point mutation, either: #a single base [[nucleotide]] is changed for another nucleotide of the genetic material (normally [[DNA]]),<ref>{{cite web |url=http://rosalind.info/glossary/point-mutation/ |title=Glossary: point mutation |publisher=Rosalind |accessdate=January 23, 2017}}</ref> or #a single base pair is inserted or deleted.<ref>{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK21955/ |title=How DNA changes affect phenotype |author= |website= |publisher=National Center for Biotechnology Information, U.S. National Library of Medicine |accessdate=January 23, 2017}}</ref> A '''nonsense mutation''' is a point mutation in a DNA sequence that leads to an early [[stop codon]].<ref>Eldon D Enger; Frederick C Ross; David B Bailey, ''Concepts in Biology'', 12th Edition (London: McGraw-Hill, 2007), p. 158</ref> This appears as a nonsense codon in the [[transcription (genetics)|transcribed]] [[mRNA]]. Most of the time, the [[protein]] that is [[translation (genetics)|translated]] from this mRNA does not work. == References == {{reflist}} {{-}} {{biology-stub}} [[Category:Genetics]] [[Category:DNA]]