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| [[Image:Conserved residues.svg|thumb|Residues conserved among various [[G protein coupled receptor]]s are highlighted in green.]]
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| In [[biology]], '''conserved sequences''' are similar or identical [[Sequence (biology)|sequences]] that occur within [[nucleic acid]] sequences (such as RNA and [[DNA sequence]]s), [[peptide sequence|protein sequences]], [[protein structure]]s or [[polysaccharide|polymeric carbohydrates]] across species ([[homology (biology)#Orthology|orthologous sequences]]) or within different molecules produced by the same organism ([[homology (biology)#Paralogy|paralogous sequences]]). In the case of cross species conservation, this indicates that a particular sequence may have been maintained by evolution despite [[speciation]]. The further back up the [[phylogenetic tree]] a particular conserved sequence may occur the more highly conserved it is said to be. Since sequence information is normally transmitted from parents to progeny by [[gene]]s, a conserved sequence implies that there is a '''conserved gene'''.
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| It is widely believed that [[mutation]] in a "highly conserved" region leads to a non-viable life form, or a form that is eliminated through [[natural selection]].
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| ==Conserved nucleic acid sequences==
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| Highly conserved DNA sequences are thought to have functional value. The role for many of these highly conserved non-coding DNA sequences is not understood. [[Ultra-conserved element]]s or sequences (UCEs or UCRs) that share 100% identity among human, mouse and rat were first described by Bejerano and colleagues in 2004.<ref name="Sci04">{{cite journal|last=Bejerano|first=G|coauthors=Pheasant, M, Makunin, I, Stephen, S, Kent, WJ, Mattick, JS, Haussler, D|title=Ultraconserved elements in the human genome.|journal=Science|date=2004-05-28|volume=304|issue=5675|pages=1321–5|pmid=15131266|accessdate=17 August 2011|doi=10.1126/science.1098119}}</ref> One recent study that eliminated four highly-conserved non-coding DNA sequences in mice yielded viable mice with no significant phenotypic differences; the authors described their findings as "unexpected".<ref name="pmid17803355">{{cite journal | author = Ahituv N, Zhu Y, Visel A, ''et al.'' | title = Deletion of ultraconserved elements yields viable mice | journal = PLoS Biol. | volume = 5 | issue = 9 | pages = e234 | year = 2007 | pmid = 17803355 | doi = 10.1371/journal.pbio.0050234 | pmc = 1964772}}</ref> Many regions of the DNA, including highly conserved DNA sequences, consist of [[repeated sequence (DNA)]] elements. One possible explanation of the null hypothesis above is that removal of only one or a subset of a repeated sequence could theoretically preserve phenotypic functioning on the assumption that one such sequence is sufficient and the repetitions are superfluous to essential life processes; it was not specified in the paper whether the eliminated sequences were repeated sequences. Although most of the conserved sequences biological function is still unknown, few conserved sequences derived transcripts showed that their expression is deregulated in human cancer tissues.<ref name="Cal07">{{cite journal|last=Calin|first=GA|coauthors=Liu, CG, Ferracin, M, Hyslop, T, Spizzo, R, Sevignani, C, Fabbri, M, Cimmino, A, Lee, EJ, Wojcik, SE, Shimizu, M, Tili, E, Rossi, S, Taccioli, C, Pichiorri, F, Liu, X, Zupo, S, Herlea, V, Gramantieri, L, Lanza, G, Alder, H, Rassenti, L, Volinia, S, Schmittgen, TD, Kipps, TJ, Negrini, M, Croce, CM|title=Ultraconserved regions encoding ncRNAs are altered in human leukemias and carcinomas.|journal=Cancer Cell|date=September 2007|volume=12|issue=3|pages=215–29|pmid=17785203|accessdate=17 August 2011|doi=10.1016/j.ccr.2007.07.027}}</ref>
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| The [[TATA box|TATA]] promoter sequence is an example of a highly conserved [[DNA sequence]], being found in most [[eukaryote]]s.
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| ==Conserved protein sequences and structures==
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| Highly conserved proteins are often required for basic cellular function, stability or reproduction. Conservation of protein sequences is indicated by the presence of identical [[amino acid]] residues at analogous parts of proteins. Conservation of protein structures is indicated by the presence of functionally equivalent, though not necessarily identical, amino acid residues and structures between analogous parts of proteins.
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| Shown below is an [[amino acid]] sequence alignment between two human [[zinc finger]] proteins, with [[GenBank]] accession numbers [http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&val=263350 AAB24882] and [http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&val=263348 AAB24881]. Alignment was carried out using the [[clustalw]] sequence alignment program. Conserved amino acid sequences are marked by strings of '''<math>\mathrm{*}</math>''' on the third line of the [[sequence alignment]]. As can be seen from this alignment, these two [[proteins]] contain a number of conserved amino acid sequences (represented by identical letters aligned between the two sequences).
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| [[Image:Zinc-finger-seq-alignment2.png|frame|center]]
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| ==Conserved polymeric carbohydrate sequences==
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| The monosaccharide sequence of the [[glycosaminoglycan]] [[heparin#Evolutionary conservation|heparin]] is conserved across a wide range of species.
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| ==Biological role of sequence conservation==
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| Sequence similarities serve as evidence for structural and functional conservation, as well as of [[evolutionary]] relationships between the sequences. Consequently, comparative analysis is the primary means by which functional elements are identified.
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| Among the most highly conserved sequences are the [[active site]]s of [[enzyme]]s and the [[binding site]]s of protein [[Receptor (biochemistry)|receptors]].
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| [[Conserved non-coding sequence]]s often harbor [[cis-regulatory element]]s which constrain evolution. Some deletions of highly conserved sequences in humans ([[hCONDELs]]) and other organisms have been suggested to be a potential cause of the anatomical and behavioral differences between humans and other mammals.<ref>{{cite journal|last=McLean|first=Cory Y.|coauthors=et al.|title=Human-specific loss of regulatory DNA and the evolution of human-specific traits|journal=Nature|date=10 March 2011|pages=216–219|doi=10.1038/nature09774|pmid=21390129|url=http://www.nature.com/nature/journal/v471/n7337/full/nature09774.html|pmc=3071156|volume=471|issue=7337}}</ref><ref>{{cite journal|last=Gross|first=Liza|title=Are "Ultraconserved" Genetic Elements Really Indispensable?|journal=PLOS Biology|date=September 2007|doi=10.1371/journal.pbio.0050253|pmid=20076686|url=http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050253|volume=5|issue=9|pmc=1964769|pages=e253}}</ref>
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| == See also ==
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| {{Portal|Evolutionary biology}}
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| * [[Ultra-conserved element]]
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| * [[Sequence alignment]]
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| * [[Sequence alignment software]]
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| * [[ClustalW]]
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| * [[UCbase]]
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| ==References==
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| {{Reflist}}
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| ==Further reading==
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| {{refbegin}}
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| *{{cite journal |author=Thompson JD, Gibson TJ, Plewniak F, Jeanmougin F, Higgins DG |title=The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools |journal=Nucleic Acids Res. |volume=25 |issue=24 |pages=4876–82 |date=December 1997 |pmid=9396791 |pmc=147148 |url=http://nar.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=9396791 |doi=10.1093/nar/25.24.4876}}
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| {{refend}}
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| {{DEFAULTSORT:Conserved Sequence}}
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| [[Category:Bioinformatics]]
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| [[Category:Computational phylogenetics]]
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| [[Category:Nucleic acids]]
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| [[Category:Protein structure]]
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| [[Category:Carbohydrates]]
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| [[Category:Population genetics]]
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| [[Category:Molecular genetics]]
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Irwin Butts is what my wife loves to contact me although I don't truly like being known as like that. Puerto Rico is exactly where he and his wife reside. To collect cash is a thing that I'm completely addicted to. Hiring is her day occupation now but she's always wanted her personal company.
Here is my blog; over the counter std test