Gene copy number
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226062719
2008-07-16T17:39:33Z
98.209.23.104
'''Gene copy number''' (also called "copy number variants"(CNVs)) refers to the genetic trait of differences in the number of copies of a particular [[gene]] present in the [[genome]] of an individual. The fact that DNA copy number differences is a widespread and common phenomena among humans was first uncovered <ref>{{cite journal |author = Sebat J, et al.
| date = 2004
| title = Large-scale copy number polymorphism in the human genome
| journal= Science
| volume = 305
| pages=525–528
| pmid = 15273396
| url = http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=15273396
| doi = 10.1126/science.1098918
}}</ref><ref>{{cite journal |author=Iafrate A, et al.
| date= 2004
| url=http://www.nature.com/ng/journal/v36/n9/abs/ng1416.html | title= Detection of large-scale variation in the human genome.
| journal = Nature Genetics
| volume= 36: 949-51
| pmid = 15286789
| doi = 10.1038/ng1416
}}</ref> following the completion of the [[human genome project]]. CNVs contribute substantially to genetic variability, with some people having deletions of some genes on only one chromosome while other people have multiple copies of some genes. It is estimated that approximately 0.4% of the genomes of unrelated people typically differ with respect to copy number.
Like other types of genetic variation, some gene copy number variants have been associated with susceptibility or resistance to disease.
Gene copy number can be elevated in [[cancer]] cells. For instance, the [[Epidermal growth factor receptor|EGFR]] copy number can be higher than normal in [[lung cancer|Non-small cell lung cancer]].<ref>{{cite journal | author=Cappuzzo F, Hirsch, et al.
| date = 2005
| title = Epidermal growth factor receptor gene and protein and gefitinib sensitivity in non-small-cell lung cancer
| journal= Journal of the National Cancer Institute
| volume= 97
| pages= 643–655
| pmid=
| doi=10.1093/jnci/dji112
}}</ref> In addition, higher copy number of [[CCL3L1]] has been associated with lower susceptibility to human HIV infection<ref>{{cite journal
| author=Gonzalez, E. et al. | journal=Science| date=2005| volume=307| pages=1434–1440
| title=The Influence of CCL3L1 Gene-Containing Segmental Duplications on HIV-1/AIDS Susceptibility
| doi=10.1126/science.1101160 | pmid=15637236}}</ref>, and low copy number of [[FCGR3B]] (the CD16 cell surface immunoglobulin receptor) can increase susceptibility to Systemic Lupus Erythematosus and similar inflammatory immune system disorders.<ref>{{cite journal
| author= Aitman T. J. et al.| journal=Nature | date=2006
| title=Copy number polymorphism in Fcgr3 predisposes to glomerulonephritis in rats and humans
| doi=10.1038/nature04489 | volume=439 | pages=851–855 | pmid=16482158 }}</ref> In humans, CNVs encompass more DNA than [[single nucleotide polymorphism]]s (SNPs) and may be responsible for a substantial amount of human phenotypic variability and disease susceptibility. <ref>{{cite journal
| journal=Nature | author = Redon, J. et al | volume=444 | pages = 444–454
| title=Global variation in copy number in the human genome |date = 2006
| doi =10.1038/nature05329 | pmid=17122850}}</ref><ref>{{cite journal | author=Freeman, JL, et al
| date= 2006
| title=Copy number variation: New insights into genome diversity
| url=http://www.genome.org/cgi/content/abstract/16/8/949
| journal = Genome Research
| volume=16
| pages= 949–61
| pmid = 16809666
| doi = 10.1101/gr.3677206
}}
</ref>
In certain cases, such as rapidly growing [[Escherichia coli]] cells, the gene copy number can be 4-fold greater for genes located near the origin of [[DNA replication]], rather than at the terminus of [[DNA replication]]. Elevating the gene copy number of a particular [[gene]] can increase the expression of the [[protein]] that it encodes.<ref>{{cite journal| author=Atkinson M, Savageau M, Myers JT, Ninfa A
| date=2003
|title=Development of Genetic Circuitry Exhibiting Toggle Switch Behavior in Escherichia Coli
| journal=Cell
| volume=113
| pages =597
| pmid=12787501
| doi=10.1016/S0092-8674(03)00346-5
}}</ref>
<ref>{{cite journal| author=Perry, G.H. et al.
| date=2007
| url=http://www.nature.com/ng/journal/v39/n10/abs/ng2123.html | title=Diet and evolution of human amylase gene copy number variation
| journal=Nature Genetics
| volume=39
| pages =1256
| pmid=17828263
}}</ref>
==Sources and notes==
<references />
==Further reading==
*[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=10471496 Genome-wide analysis of DNA copy-number changes using cDNA microarrays] "Gene amplifications and deletions frequently contribute to tumorigenesis. Characterization of these DNA copy-number changes is important for both the basic understanding of cancer and its diagnosis."
*{{cite web|url=http://www.newscientist.com/article.ns?id=mg18324592.000 | publisher= New Scientist| date=[[August 7]], [[2004]]| title=Huge genetic variation in healthy people}}
*{{cite web|url=http://www.nature.com/ng/journal/v36/n9/abs/ng0904-931.html | publisher= Nature Genetics| date=[[September 1]], [[2004]]| title=As normal as normal can be}}
*{{cite web|url= http://www.nature.com/nature/journal/v437/n7062/full/4371084a.html | publisher= Nature| date=[[October 20]], [[2005]]| title=Human Genome: Patchwork people}}
*{{cite web|url= http://www.newscientist.com/article/dn10646-gene-duplications-may-define-who-you-are-.html | publisher= New Scientist| title=Human DNA is far more varied than thought | date=[[November 22]], [[2006]]| title=Gene duplications may define who you are}}
*{{cite web| url=http://news.nationalgeographic.com/news/2006/11/061122-human-genetics.html | publisher=National Geographic | title=DNA varies more widely from person to person, Genetic maps reveal| date=[[November 22]], [[2006]]}}
*{{cite web| url=http://www.nature.com/ng/journal/v39/n7s/pdf/ng0707s-S1.pdf | publisher=Nature Genetics | title=Finding the right lenses| date=[[July 1]], [[2007]]|format=PDF}}
==External links==
* [http://www.nslij-genetics.org/cnv/ A bibliography on copy number variation]
[[Category:Genetics]]
[[Category:Molecular biology]]
{{genetics-stub}}
[[de:Gene copy number variants]]
[[ja:コピー数多型]]
[[tr:Gen kopya sayısı]]