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Nova páxina: "{{entradución}} A '''sintenia''' (do grego σύν, ''syn'', ao longo + ταινία, ''tainiā'', banda, fita) In classical genetics, '''synteny''' describes the physical c..."
 
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{{entradución}}
A '''sintenia''' (do grego σύν, ''syn'', ao longo + ταινία, ''tainiā'', banda, fita) é a presenza simultánea no mesmo [[cromosoma]] de dous ou máis [[loci]] xenéticos nun individuo ou especie, independentemente do seu [[ligamento xenético]]. A noción de sintenia úsase moito para describir a conservación da orde dos [[xene]]s entre dúas especies emparentadas.
 
In [[classical genetics]], '''synteny''' describes the physical co-localization of [[Locus (genetics)|genetic loci]] on the same [[chromosome]] within an individual or [[species]]. The concept is related to [[genetic linkage]]: Linkage between two loci is established by the observation of lower-than-expected [[Genetic recombination|recombination]] frequencies between them. In contrast, any loci on the same chromosome are by definition syntenic, even if their recombination frequency cannot be distinguished from unlinked loci by practical experiments. Thus, in theory, all linked loci are syntenic, but not all syntenic loci are necessarily linked. Similarly, in [[genomics]], the genetic loci on a chromosome are syntenic regardless of whether this relationship can be established by experimental methods such as [[DNA sequencing]]/assembly, [[genome walking]], physical localization or [[happy mapping|hap-mapping]].
 
Sintenia e ligamento xenético son conceptos relacionados pero diferentes. O ligamento entre dous loci establécese normalmente pola observación de frecuencias de [[recombinación xenética]] entre eles menores do esperado. Os loci que están nun mesmo cromosoma son por definición sinténicos, aínda que ás veces as súas frecuencias de recombinación non se poden distinguir das dos xenes non ligados. Por tanto, en teoría, todos os loci ligados son sinténicos, pero non todos os loci sinténicos están necesariamente ligados.
Students of genetics employ the term synteny to describe the situation in which two genetic loci have been assigned to the same chromosome but still may be separated by a large enough distance in map units that genetic linkage has not been demonstrated.
 
As especies que se separaron evolutivamente hai relativamente pouco tempo presentan bloques de xenes situados nos seus [[xenoma]]s en posicións relativas iguais. Por exemplo, moitos dos xenes humanos son sinténicos cos doutros mamíferos. O estudo da sintenia pode servir para coñecer os rearranxos que sufriu o xenoma ao longo da evolución. <ref>http://www.britannica.com/EBchecked/topic/262934/heredity/262018/Synteny?anchor=ref944552</ref>:
 
The Encyclopædia Britannica gives the following description of synteny<ref>http://www.britannica.com/EBchecked/topic/262934/heredity/262018/Synteny?anchor=ref944552</ref>:
{{Quote| Genomic sequencing and mapping have enabled comparison of the general structures of genomes of many different species. The general finding is that organisms of relatively recent divergence show similar blocks of genes in the same relative positions in the genome. This situation is called synteny, translated roughly as possessing common chromosome sequences. For example, many of the genes of humans are syntenic with those of other mammals—not only apes but also cows, mice, and so on. Study of synteny can show how the genome is cut and pasted in the course of evolution.}}
== Shared synteny ==
 
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TheO termtermo isé sometimesás alsoveces usedutilizado topara describedescribir preservationa ofpreservación theda preciseorde orderprecisa ofde genesxenes onnun acromosoma chromosomeherdada passeddun downantepasado fromcomún, a common ancestor,<ref>{{cite journal |author=Engström PG, Ho Sui SJ, Drivenes O, Becker TS, Lenhard B |title=Genomic regulatory blocks underlie extensive microsynteny conservation in insects |journal=Genome Res. |volume=17 |issue=12 |pages=1898–908 |year=2007 |pmid=17989259 |doi=10.1101/gr.6669607 |pmc=2099597}}</ref><ref name="pmid17989258">{{cite journal |author=Heger A, Ponting CP |title=Evolutionary rate analyses of orthologs and paralogs from 12 Drosophila genomes |journal=Genome Res. |volume=17 |issue=12 |pages=1837–49 |year=2007 |pmid=17989258 |doi=10.1101/gr.6249707 |pmc=2099592}}</ref><ref name="pmid17983469">{{cite journal |author=Poyatos JF, Hurst LD |title=The determinants of gene order conservation in yeasts |journal=Genome Biol |volume=8 |issue=11 |pages=R233 |year=2007 |pmid=17983469 |doi=10.1186/gb-2007-8-11-r233 |pmc=2258174}}</ref><ref name="pmid17434902">{{cite journal |author=Dawson DA, Akesson M, Burke T, Pemberton JM, Slate J, Hansson B |title=Gene order and recombination rate in homologous chromosome regions of the chicken and a passerine bird |journal=Mol. Biol. Evol. |volume=24 |issue=7 |pages=1537–52 |year=2007 |pmid=17434902 |doi=10.1093/molbev/msm071}}</ref> althoughaínda manyque geneticistsmoitis rejectxenetistas thisrexeitan useeste ofuso thedo termtermo. <ref>{{cite journal | author=Passarge, E., B. Horsthemke & R. A. Farber|year=1999|title=Incorrect use of the term synteny|journal=Nature Genetics|volume=23 | issue=4|pages=387|doi=10.1038/70486}}</ref> The analysis of synteny in the gene order sense has several applications in genomics. Shared synteny is one of the most reliable criteria for establishing the [[orthology]] of genomic regions in different species. Additionally, exceptional conservation of synteny can reflect important functional relationships between genes. For example, the order of genes in the "[[Homeobox|Hox cluster]]", which are key determinants of the [[animal]] [[body plan]] and which interact with each other in critical ways, is essentially preserved throughout the animal kingdom.{{Citation needed|date=January 2008}} Patterns of shared synteny or synteny breaks can also be used as [[Trait (biology)|characters]] to infer the [[phylogenetic]] relationships among several species, and even to infer the genome organization of extinct ancestral species. A qualitative distinction is sometimes drawn between '''macrosynteny''', preservation of synteny in large portions of a chromosome, and '''microsynteny''', preservation of synteny for only a few genes at a time.▼
 
A análise da sintenia no sentido de orde dos xenes ten moitas aplicacións en [[xenómica]]. A sintenia compartida é un dos criterios máis fiables para establecer a [[ortoloxía]] de rexións xenómicos en diferentes especies. A conservación excepcional da sintenia en certos xenes pode indicar que eses xenes teñen importantes relacións funcionais e deben estar xuntos, por exemplo no casp do clúster de xenes "[[Homeobox]]", que determinan o plan de organización do animal e que está moi conservado. Os patróns da sintenia compartida ou as roturas da sintenia poden utilizarse para inferir [[filoxenia]]s e mesmo para deducir a organización xenómica de especies extintas ancestrais. Xeralmente faise unha distinción cualitativa entre '''macrosintenia''' (preservación da sintenia en grandes porcións do cromosoma) e '''microsintenia''' (preservación da sintenia en só uns poucos xenes á vez).
▲The term is sometimes also used to describe preservation of the precise order of genes on a chromosome passed down from a common ancestor,<ref>{{cite journal |author=Engström PG, Ho Sui SJ, Drivenes O, Becker TS, Lenhard B |title=Genomic regulatory blocks underlie extensive microsynteny conservation in insects |journal=Genome Res. |volume=17 |issue=12 |pages=1898–908 |year=2007 |pmid=17989259 |doi=10.1101/gr.6669607 |pmc=2099597}}</ref><ref name="pmid17989258">{{cite journal |author=Heger A, Ponting CP |title=Evolutionary rate analyses of orthologs and paralogs from 12 Drosophila genomes |journal=Genome Res. |volume=17 |issue=12 |pages=1837–49 |year=2007 |pmid=17989258 |doi=10.1101/gr.6249707 |pmc=2099592}}</ref><ref name="pmid17983469">{{cite journal |author=Poyatos JF, Hurst LD |title=The determinants of gene order conservation in yeasts |journal=Genome Biol |volume=8 |issue=11 |pages=R233 |year=2007 |pmid=17983469 |doi=10.1186/gb-2007-8-11-r233 |pmc=2258174}}</ref><ref name="pmid17434902">{{cite journal |author=Dawson DA, Akesson M, Burke T, Pemberton JM, Slate J, Hansson B |title=Gene order and recombination rate in homologous chromosome regions of the chicken and a passerine bird |journal=Mol. Biol. Evol. |volume=24 |issue=7 |pages=1537–52 |year=2007 |pmid=17434902 |doi=10.1093/molbev/msm071}}</ref> although many geneticists reject this use of the term.<ref>{{cite journal | author=Passarge, E., B. Horsthemke & R. A. Farber|year=1999|title=Incorrect use of the term synteny|journal=Nature Genetics|volume=23 | issue=4|pages=387|doi=10.1038/70486}}</ref> The analysis of synteny in the gene order sense has several applications in genomics. Shared synteny is one of the most reliable criteria for establishing the [[orthology]] of genomic regions in different species. Additionally, exceptional conservation of synteny can reflect important functional relationships between genes. For example, the order of genes in the "[[Homeobox|Hox cluster]]", which are key determinants of the [[animal]] [[body plan]] and which interact with each other in critical ways, is essentially preserved throughout the animal kingdom.{{Citation needed|date=January 2008}} Patterns of shared synteny or synteny breaks can also be used as [[Trait (biology)|characters]] to infer the [[phylogenetic]] relationships among several species, and even to infer the genome organization of extinct ancestral species. A qualitative distinction is sometimes drawn between '''macrosynteny''', preservation of synteny in large portions of a chromosome, and '''microsynteny''', preservation of synteny for only a few genes at a time.
 
==EtymologyNotas==
''Synteny'' is a [[neologism]] meaning "on the same ribbon"; [[Ancient Greek|Greek]]: ==Notas==
{{listaref}}
 
==Véxase tamén==
===Outros artigos===
* [[Elemento ultraconservado]]
* [[Ultra-conserved element]]
* [[Xenoma humano]]
 
===Ligazóns externas===
Traído desde «https://gl.wikipedia.org/wiki/Sintenia»