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In [[DNA]], the coding region is flanked by the [[Promoter (genetics)|promoter sequence]] on the 5' end of the [[template strand]] and the termination sequence on the 3' end. During [[Transcription (biology)|transcription]], the [[RNA Polymerase|RNA Polymerase (RNAP)]] binds to the promoter sequence and moves along the template strand to the coding region. RNAP then adds RNA [[nucleotide]]s complementary to the coding region in order to form the [[mRNA]], substituting [[uracil]] in place of [[thymine]].<ref name=":2">Overview of transcription. (n.d.). Retrieved from <nowiki>https://www.khanacademy.org/science/biology/gene-expression-central-dogma/transcription-of-dna-into-rna/a/overview-of-transcription</nowiki>.</ref> This continues until the RNAP reaches the termination sequence.<ref name=":2" />
After transcription and maturation, the [[mature mRNA]] formed encompasses multiple parts important for its eventual translation into [[protein]]. The coding region in an mRNA is flanked by the [[Five prime untranslated region|5' untranslated region]] (5'-UTR) and [[Three prime untranslated region|3' untranslated region]] (3'-UTR),<ref name=":12"/> the [[Five-prime cap|5' cap]], and [[Poly a tail|Poly-A tail]]. During [[Translation (biology)|translation]], the [[ribosome]] facilitates the attachment of the [[Transfer RNA|tRNAs]] to the coding region, 3 nucleotides at a time ([[codons]]).<ref>{{Cite web|url=https://www.nature.com/scitable/topicpage/translation-dna-to-mrna-to-protein-393/|title=Translation: DNA to mRNA to Protein|last=Clancy|first=Suzanne|date=2008|website=Scitable: By Nature Education
[[File:Mature_mRNA.png|thumb|413x413px|The coding region (teal) is flanked by untranslated regions, the 5' cap, and the poly(A) tail which together form the '''mature mRNA'''.<ref>{{Citation|last=Plociam|title=English: The structure of a mature eukaryotic mRNA. A fully processed mRNA includes the 5' cap, 5' UTR, coding region, 3' UTR, and poly(A) tail.|date=2005-08-08|url=https://commons.wikimedia.org/wiki/File:Mature_mRNA.png|access-date=2019-11-19}}</ref>]]
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While identification of [[open reading frames]] within a DNA sequence is straightforward, identifying coding sequences is not, because the cell translates only a subset of all open reading frames to proteins.<ref>{{cite journal | vauthors = Furuno M, Kasukawa T, Saito R, Adachi J, Suzuki H, Baldarelli R, Hayashizaki Y, Okazaki Y | display-authors = 6 | title = CDS annotation in full-length cDNA sequence | journal = Genome Research | volume = 13 | issue = 6B | pages = 1478–87 | date = June 2003 | pmid = 12819146 | pmc = 403693 | doi = 10.1101/gr.1060303 | publisher = Cold Spring Harbor Laboratory Press }}</ref> Currently CDS prediction uses sampling and sequencing of mRNA from cells, although there is still the problem of determining which parts of a given mRNA are actually translated to protein. CDS prediction is a subset of [[gene prediction]], the latter also including prediction of DNA sequences that code not only for protein but also for other functional elements such as RNA genes and regulatory sequences.
In both [[prokaryote]]s and [[eukaryote]]s, [[Overlapping gene|gene overlapping]] occurs relatively often in both DNA and RNA viruses as an evolutionary advantage to reduce genome size while retaining the ability to produce various proteins from the available coding regions.<ref>{{cite journal | vauthors = Rogozin IB, Spiridonov AN, Sorokin AV, Wolf YI, Jordan IK, Tatusov RL, Koonin EV | title = Purifying and directional selection in overlapping prokaryotic genes | language =
== See also ==
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