Editing Coding region (section)

== Mutations ==
[[Mutation]]s in the coding region can have very diverse effects on the phenotype of the organism. While some mutations in this region of DNA/RNA can result in advantageous changes, others can be harmful and sometimes even lethal to an organism's survival. In contrast, changes in the non-coding region may not always result in detectable changes in phenotype.

=== Mutation types ===
[[File:Different_Types_of_Mutations.png|thumb|381x381px|Examples of the various forms of '''point mutations''' that may exist within coding regions. Such alterations may or may not have phenotypic changes, depending on whether or not they code for different amino acids during translation.<ref>{{Citation|last=Jonsta247|title=English: Example of silent mutation|date=2013-05-10|url=https://commons.wikimedia.org/wiki/File:Different_Types_of_Mutations.png|access-date=2019-11-19}}</ref>]]
There are various forms of mutations that can occur in coding regions. One form is [[silent mutation]]s, in which a change in nucleotides does not result in any change in amino acid after transcription and translation.<ref name=":3">Yang, J. (2016, March 23). What are Genetic Mutation? Retrieved from https://www.singerinstruments.com/resource/what-are-genetic-mutation/ .</ref> There also exist [[nonsense mutation]]s, where base alterations in the coding region code for a premature stop codon, producing a shorter final protein. [[Point mutation|Point mutations]], or single base pair changes in the coding region, that code for different amino acids during translation, are called [[missense mutation]]s. Other types of mutations include [[frameshift mutation]]s such as [[Insertion mutation|insertions]] or [[Deletion (genetics)|deletions]].<ref name=":3" />

=== Formation ===
Some forms of mutations are [[Heredity|hereditary]] ([[germline mutation]]s), or passed on from a parent to its offspring.<ref name=":4">What is a gene mutation and how do mutations occur? - Genetics Home Reference - NIH. (n.d.). Retrieved from https://ghr.nlm.nih.gov/primer/mutationsanddisorders/genemutation .</ref> Such mutated coding regions are present in all cells within the organism. Other forms of mutations are acquired ([[somatic mutation]]s) during an organism's lifetime, and may not be constant cell-to-cell.<ref name=":4" /> These changes can be caused by [[mutagen]]s, [[carcinogen]]s, or other environmental agents (ex. [[Ultraviolet|UV]]). Acquired mutations can also be a result of copy-errors during [[DNA replication]] and are not passed down to offspring. Changes in the coding region can also be [[De novo mutation|de novo]] (new); such changes are thought to occur shortly after [[Fertilisation|fertilization]], resulting in a mutation present in the offspring's DNA while being absent in both the sperm and egg cells.<ref name=":4" />

=== Prevention ===
There exist multiple transcription and translation mechanisms to prevent lethality due to deleterious mutations in the coding region. Such measures include [[Proofreading (biology)|proofreading]] by some [[DNA polymerase|DNA Polymerases]] during replication, [[DNA mismatch repair|mismatch repair]] following replication,<ref>{{Cite web |title=DNA proofreading and repair (article) |url=https://www.khanacademy.org/science/biology/dna-as-the-genetic-material/dna-replication/a/dna-proofreading-and-repair |access-date=2023-05-22 |website=Khan Academy |language=en}}</ref> and the '[[Wobble hypothesis|Wobble Hypothesis]]' which describes the [[Degeneracy (biology)|degeneracy]] of the third base within an mRNA codon.<ref>Peretó J. (2011) Wobble Hypothesis (Genetics). In: Gargaud M. et al. (eds) Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg</ref>