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| [[Image:AT-GC.jpg|thumb|400px|Nucleotide bonds showing AT and GC pairs. Arrows point to the [[hydrogen bond]]s.]]
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| In [[molecular biology]] and [[genetics]], '''GC-content''' (or '''guanine-cytosine content''') is the percentage of [[nitrogenous bases]] on a [[DNA]] molecule that are either [[guanine]] or [[cytosine]] (from a possibility of four different ones, also including [[adenine]] and [[thymine]]).<ref>[http://cancerweb.ncl.ac.uk/cgi-bin/omd?GC+content Definition of GC – content on CancerWeb of [[Newcastle University]],UK]</ref> This may refer to a specific fragment of DNA or [[RNA]], or that of the [[Genome|whole genome]]. When it refers to a fragment of the genetic material, it may denote the GC-content of part of a gene (domain), single gene, group of genes (or gene clusters), or even a non-coding region. G (guanine) and C (cytosine) undergo a specific [[hydrogen bonding]], whereas A (adenine) bonds specifically with T (thymine).
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| The GC pair is bound by three [[hydrogen bond]]s, while AT pairs are bound by two hydrogen bonds. DNA with high GC-content is more stable than DNA with low GC-content; however, the hydrogen bonds do not stabilize the DNA significantly, and stabilization is due mainly to stacking interactions.<ref name ="Yakovchuk2006">{{cite journal |author=Yakovchuk P, Protozanova E, Frank-Kamenetskii MD |title=Base-stacking and base-pairing contributions into thermal stability of the DNA double helix |journal=Nucleic Acids Res. |volume=34 |issue=2 |pages=564–74 |year=2006 |pmid=16449200 |pmc=1360284 |doi=10.1093/nar/gkj454 |url=http://nar.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=16449200}}</ref>
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| In spite of the higher [[thermostability]] conferred to the genetic material, it is envisaged that cells with DNA of high GC-content undergo [[Autolysis (biology)|autolysis]], thereby reducing the longevity of the cell ''per se''.<ref>{{cite journal |author=Levin RE, Van Sickle C |title=Autolysis of high-GC isolates of Pseudomonas putrefaciens |journal=Antonie Van Leeuwenhoek |volume=42 |issue=1–2 |pages=145–55 |year=1976 |pmid=7999 |doi=10.1007/BF00399459 }}</ref> Due to the robustness endowed to the genetic materials in high GC organisms, it was commonly believed that the GC content played a vital part in adaptation temperatures, a hypothesis that has recently been refuted.<ref>{{cite journal |author=Hurst LD, Merchant AR |title=High guanine-cytosine content is not an adaptation to high temperature: a comparative analysis amongst prokaryotes |journal=Proc. Biol. Sci. |volume=268 |issue=1466 |pages=493–7 |date=March 2001 |pmid=11296861 |pmc=1088632 |doi=10.1098/rspb.2000.1397 |url=http://journals.royalsociety.org/openurl.asp?genre=article&issn=0962-8452&volume=268&issue=1466&spage=493}}</ref>
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| However, the same study showed a strong correlation between higher temperatures and the GC content of structured [[RNA]]s (such as [[ribosomal RNA]], [[transfer RNA]], and many other [[non-coding RNA]]s); GC [[base pair]]s are more stable than AU base pairs, due to the fact that GC bonds have 3 hydrogen bonds and AU only has 2 hydrogen bonds, which makes high-GC-content RNA structures more tolerant of high temperatures.
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| More recently, the first large-scale systematic gene-centric association analysis demonstrated the correlation between GC content and temperature for certain genomic regions while not for others.<ref>{{cite journal |author=Zheng H, Wu H |title=Gene-centric association analysis for the correlation between the guanine-cytosine content levels and temperature range conditions of prokaryotic species |journal=BMC Bioinformatics |volume=11 |pages=S7 |date=December 2010 |doi=10.1186/1471-2105-11-S11-S7 |pmc=3024870 |pmid=21172057}}</ref>
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| In [[PCR]] experiments, the GC-content of [[primer (molecular biology)|primers]] are used to predict their [[Polymerase chain reaction|annealing temperature]] to the template DNA. A higher GC-content level indicates a higher melting temperature.
| | You start in a pair of a lovely island where your own personal peaceful village is having beaches and woods till the enemies known since the BlackGuard led by Lieutenant Hammerman invades your snowdonia. After managing to guard against a tiny bit invasion force, he provides avenge his loss all through battle.<br><br>when you are locating that handle system tough on use, optimize the surroundings within your activity. The default manage community might not be needed for everyone. Some individuals prefer a better let you know screen, a set linked with more sensitive management also known as perhaps an inverted structure. In several tutorial gaming, you may master these from the setting's area.<br><br>Gallstones are known as your games primary forex. The Jewels are previously used to purchase resources along to speeding up numerous vital tasks. The Gemstones can also be was considered to buy bonus items. Apart from that, it can possibly let the leader detectable any undesired debris if you would like to obtain a much more gems. Players may very well obtain Gems through concluding numerous tasks or perchance using the clash of clans get into available online.<br><br>On the internet games acquire more regarding offer your son or it may be daughter than only the possibility to capture points. Try [http://Www.wired.com/search?query=deciding deciding] on games that instruct your infant some thing. In view that an example, sports physical exertions video games will assist your youngster learn an guidelines for game titles, and exactly how around the games are played out and. Check out some testimonials to assist you to discover game titles which experts claim supply a learning past experience instead of just mindless, repeated motion.<br><br>The organization testing has apparent which is this appraisement algorithm training consists of a alternation of beeline band quests. They are n't things to consider types of of arced graphs. I will explain the later.<br><br>Your tutorial will guide you through your first few raids, constructions, and upgrades, but youre left to your personal personal wiles pretty quickly. Your buildings take real-time to construct and upgrade, your army units although recruit, and your useful resource buildings take time to create food and gold. Like all of his or her genre cousins, Throne Haste is meant to played in multiple short bursts exactly like. This type of fanatical gaming definitely works more complete on mobile devices which are always with you that will send push notifications when timed tasks are carried out. Then again, the success of a lot of hit Facebook games through the years indicates that people check Facebook often enough supplementations short play sessions employment there too.<br><br>At master game play regarding shooter video games, pro your weapons. See everything there is to know about each and every weapon style in video game. Each weapon excels found in certain ways, but occurs short in others. If you cherished this posting and you would like to receive more info regarding [http://prometeu.net hack clash of clans android] kindly take a look at our site. When you know that pluses and minuses relating to each weapon, you may easily use them to double advantage. |
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| == Determination of GC content ==
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| GC content is usually expressed as a percentage value, but sometimes as a ratio (called '''G+C ratio''' or '''GC-ratio'''). GC-content percentage is calculated as<ref>{{cite book | author =Madigan,MT. and Martinko JM. | title = Brock biology of microorganisms| edition = 10th | publisher =Pearson-Prentice Hall | year = 2003| isbn = 84-205-3679-2}}</ref>
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| :<math>\cfrac{G+C}{A+T+G+C}\times\ 100</math>
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| whereas the AT/GC ratio is calculated as<ref>[http://www.biochem.northwestern.edu/holmgren/Glossary/Definitions/Def-A/A+T_G+C_ratio.html Definition of GC-ratio on Northwestern University, IL, USA]</ref>
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| :<math>\cfrac{A+T}{G+C}</math> .
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| The GC-content percentages as well as GC-ratio can be measured by several means, but one of the simplest methods is to measure what is called the [[DNA melting|melting temperature]] of the [[DNA]] [[double helix]] using [[spectrophotometry]]. The [[absorbance]] of [[DNA]] at a [[wavelength]] of 260 [[Nanometer|nm]] increases fairly sharply when the double-stranded [[DNA]] separates into two single strands when sufficiently heated.<ref>{{cite journal |author=Wilhelm J, Pingoud A, Hahn M |title=Real-time PCR-based method for the estimation of genome sizes |journal=Nucleic Acids Res. |volume=31 |issue=10 |pages=e56 |date=May 2003 |pmid=12736322 |pmc=156059 |url=http://nar.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=12736322 |doi=10.1093/nar/gng056}}</ref> The most commonly used protocol for determining GC ratios uses [[flow cytometry]] for large number of samples.<ref>{{cite journal |author=Vinogradov AE |title=Measurement by flow cytometry of genomic AT/GC ratio and genome size |journal=Cytometry |volume=16 |issue=1 |pages=34–40 |date=May 1994 |pmid=7518377 |doi=10.1002/cyto.990160106 }}</ref> | |
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| In alternative manner, if the DNA or RNA molecule under investigation has been [[sequenced]] then the GC-content can be accurately calculated by simple arithmetic or by using the [http://www.basic.northwestern.edu/biotools/oligocalc.html free online GC calculator].
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| == GC ratio of genomes ==
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| GC ratios within a genome is found to be markedly variable. These variations in GC ratio within the genomes of more complex organisms result in a mosaic-like formation with islet regions called [[Isochore (genetics)|isochores]].<ref>{{cite journal |author=Bernardi G |title=Isochores and the evolutionary genomics of vertebrates |journal=Gene |volume=241 |issue=1 |pages=3–17 |date=January 2000 |pmid=10607893 |url=http://linkinghub.elsevier.com/retrieve/pii/S0378-1119(99)00485-0 |doi=10.1016/S0378-1119(99)00485-0}}</ref> This results in the variations in staining intensity in the [[chromosomes]].<ref>{{cite journal |author=Furey TS, Haussler D |title=Integration of the cytogenetic map with the draft human genome sequence |journal=Hum. Mol. Genet. |volume=12 |issue=9 |pages=1037–44 |date=May 2003 |pmid=12700172 |url=http://hmg.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=12700172 |doi=10.1093/hmg/ddg113}}</ref> GC-rich isochores include in them many protein coding genes, and thus determination of ratio of these specific regions contributes in mapping gene-rich regions of the genome.<ref>{{cite journal |author=Sumner AT, de la Torre J, Stuppia L |title=The distribution of genes on chromosomes: a cytological approach |journal=J. Mol. Evol. |volume=37 |issue=2 |pages=117–22 |date=August 1993 |pmid=8411200 |doi=10.1007/BF02407346 }}</ref><ref>{{cite journal |author=Aïssani B, Bernardi G |title=CpG islands, genes and isochores in the genomes of vertebrates |journal=Gene |volume=106 |issue=2 |pages=185–95 |date=October 1991 |pmid=1937049 |doi=10.1016/0378-1119(91)90198-K }}</ref>
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| == GC ratios and coding sequence ==
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| Within a long region of genomic sequence, genes are often characterised by having a higher GC-content in contrast to the background GC-content for the entire genome. Evidence of GC ratio with that of length of the [[coding region]] of a [[gene]] has shown that the length of the coding sequence is directly proportional to higher G+C content.<ref>{{cite journal |author=Pozzoli U, Menozzi G, Fumagalli M, ''et al'' |title=Both selective and neutral processes drive GC content evolution in the human genome |journal=BMC Evol. Biol. |volume=8 |pages=99 |year=2008 |pmid=18371205 |pmc=2292697 |doi=10.1186/1471-2148-8-99 |url=http://www.biomedcentral.com/1471-2148/8/99}}</ref> This has been pointed to the fact that the [[stop codon]] has a bias towards A and T nucleotides, and, thus, the shorter the sequence the higher the AT bias.<ref>{{cite journal |author=Wuitschick JD, Karrer KM |title=Analysis of genomic G + C content, codon usage, initiator codon context and translation termination sites in ''Tetrahymena thermophila'' |journal=J. Eukaryot. Microbiol. |volume=46 |issue=3 |pages=239–47 |year=1999 |pmid=10377985 |doi=10.1111/j.1550-7408.1999.tb05120.x }}</ref>
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| == Application in systematics ==
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| GC content is found to be variable with different organisms, the process of which is envisaged to be contributed to by variation in [[Gene-centered view of evolution|selection]], mutational bias, and biased recombination-associated [[DNA repair]].<ref>{{cite journal |author=Birdsell JA |title=Integrating genomics, bioinformatics, and classical genetics to study the effects of recombination on genome evolution |journal=Mol. Biol. Evol. |volume=19 |issue=7 |pages=1181–97 |date=1 July 2002|pmid=12082137 |url=http://mbe.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=12082137 }}</ref> The [[species problem]] in prokaryotic taxonomy has led to various suggestions in classifying bacteria, and the ''ad hoc committee on reconciliation of approaches to bacterial systematics'' has recommended use of GC ratios in higher level hierarchical classification.<ref>{{cite journal |doi=10.1099/00207713-37-4-463 |author=Wayne LG, ''et al'' |title=Report of the ad hoc committee on reconciliation of approaches to bacterial systematic |journal=International journal of systematic bacteriology |volume=37 |issue=4 |pages=463–4 |year=1987}}</ref> For example, the [[Actinobacteria]] are characterised as "high GC-content [[bacterium|bacteria]]".<ref>[http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=1760&lvl=3&lin=f&keep=1&srchmode=1&unlock Taxonomy browser on NCBI]</ref> In ''[[Streptomyces coelicolor]]'' A3(2), GC content is 72%.<ref>[http://www.ncbi.nlm.nih.gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=242 Whole genome data of "Streptomyces coelicolor" A3(2) on NCBI]</ref> The GC-content of [[Yeast]] (''[[Saccharomyces cerevisiae]]'') is 38%,<ref>[http://www.ncbi.nlm.nih.gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=128 Whole genome data of ''Saccharomyces cerevisiae'' on NCBI]</ref> and that of another common [[model organism]], Thale Cress (''[[Arabidopsis thaliana]]''), is 36%.<ref>[http://www.ncbi.nlm.nih.gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=116 Whole genome data of '' Arabidopsis thaliana'' on NCBI]</ref> Because of the nature of the [[genetic code]], it is virtually impossible for an organism to have a genome with a GC-content approaching either 0% or 100%. A species with an extremely low GC-content is ''[[Plasmodium falciparum]]'' (GC% = ~20%),<ref>[http://www.ncbi.nlm.nih.gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=148 Whole genome data of ''Plasmodium falciparum'' on NCBI]</ref> and it is usually common to refer to such examples as being AT-rich instead of GC-poor.<ref>{{cite journal |author=Musto H, Cacciò S, Rodríguez-Maseda H, Bernardi G |title=Compositional constraints in the extremely GC-poor genome of ''Plasmodium falciparum'' |journal=Mem. Inst. Oswaldo Cruz |volume=92 |issue=6 |pages=835–41 |year=1997 |pmid=9566216 |url=http://www.scielo.br/pdf/mioc/v92n6/3431.pdf |doi=10.1590/S0074-02761997000600020}}</ref>
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| == References ==
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| {{Reflist|2}}
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| == External links ==
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| # [http://insilico.ehu.es/oligoweb/index2.php?m=all Table with GC-content of all sequenced prokaryotes]
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| # [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=2&lvl=3&srchmode=1&keep=1&unlock Taxonomic browser of bacteria based on GC ratio on NCBI website].
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| # [http://esper.lab.nig.ac.jp/study/genome/?page=genome_composition_database_species_list GC ratio in diverse species].
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| {{DEFAULTSORT:Gc-Content}}
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| [[Category:DNA]]
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| [[Category:Molecular biology]]
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| [[Category:Biological classification]]
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| [[Category:Genetics]]
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You start in a pair of a lovely island where your own personal peaceful village is having beaches and woods till the enemies known since the BlackGuard led by Lieutenant Hammerman invades your snowdonia. After managing to guard against a tiny bit invasion force, he provides avenge his loss all through battle.
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