tag:blogger.com,1999:blog-84029055302271642692023-11-15T05:24:00.571-08:00Loss of heterozygositypotstubhttp://www.blogger.com/profile/01645040450324992818noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-8402905530227164269.post-34133493627075246042007-08-28T15:06:00.000-07:002007-08-28T15:07:24.215-07:00Loss of heterozygosity<div id="globalWrapper"> <div id="column-content"> <div id="content"> <a name="top" id="top"></a> <div id="siteNotice"><script type="text/javascript" language="JavaScript"> <!-- document.writeln("\x3cdiv style=\"text-align:right; font-size:80%\"\x3eYour \x3cb\x3e\x3ca href=\"http://wikimediafoundation.org/wiki/Fundraising\" class=\"extiw\" title=\"wikimedia:Fundraising\"\x3econtinued donations\x3c/a\x3e\x3c/b\x3e keep Wikipedia running! \x3c/div\x3e\n"); --> </script><div style="text-align: right; font-size: 80%;">Your <b><a href="http://wikimediafoundation.org/wiki/Fundraising" class="extiw" title="wikimedia:Fundraising">continued donations</a></b> keep Wikipedia running! </div> </div> <h1 class="firstHeading">Loss of heterozygosity</h1> <div id="bodyContent"> <h3 id="siteSub">From Wikipedia, the free encyclopedia</h3> <div id="jump-to-nav">Jump to: <a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity#column-one">navigation</a>, <a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity#searchInput">search</a></div> <!-- start content --> <p><b>Loss of heterozygosity (LOH)</b> in a <a href="http://en.wikipedia.org/wiki/Cell_%28biology%29" title="Cell (biology)">cell</a> represents the loss of one parent's contribution to part of the cell's <a href="http://en.wikipedia.org/wiki/Genome" title="Genome">genome</a>. LOH can arise via several pathways, including deletion, gene conversion, mitotic recombination and chromosome loss. The latter event is sometimes followed by duplication of the remaining chromosome.</p> <p><br /></p> <table id="toc" class="toc" summary="Contents"> <tbody><tr> <td> <div id="toctitle"> <h2>Contents</h2> <span class="toctoggle">[<a href="javascript:toggleToc()" class="internal" id="togglelink">hide</a>]</span></div> <ul><li class="toclevel-1"><a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity#In_cancer"><span class="tocnumber">1</span> <span class="toctext">In cancer</span></a> <ul><li class="toclevel-2"><a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity#Retinoblastoma"><span class="tocnumber">1.1</span> <span class="toctext">Retinoblastoma</span></a></li></ul> </li><li class="toclevel-1"><a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity#Detection"><span class="tocnumber">2</span> <span class="toctext">Detection</span></a></li><li class="toclevel-1"><a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity#See_also"><span class="tocnumber">3</span> <span class="toctext">See also</span></a></li></ul> </td> </tr> </tbody></table> <script type="text/javascript"> //<![CDATA[ if (window.showTocToggle) { var tocShowText = "show"; var tocHideText = "hide"; showTocToggle(); } //]]> </script> <p><a name="In_cancer" id="In_cancer"></a></p> <h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&action=edit&section=1" title="Edit section: In cancer">edit</a>]</span> <span class="mw-headline">In cancer</span></h2> <p>It is a common occurrence in <a href="http://en.wikipedia.org/wiki/Cancer" title="Cancer">cancer</a>, where it indicates the absence of <a href="http://en.wikipedia.org/wiki/Tumor_suppressor_gene" title="Tumor suppressor gene">tumor suppressor gene</a> in the lost region. However, many people go healthy with such a loss, because there still is one functional gene left on the other chromosome of the <a href="http://en.wikipedia.org/w/index.php?title=Chromosome_pair&action=edit" class="new" title="Chromosome pair">chromosome pair</a>. However, the remaining copy of the tumor suppressor gene can be inactivated by a <a href="http://en.wikipedia.org/wiki/Point_mutation" title="Point mutation">point mutation</a>, leaving no tumor suppressor gene to protect the body.</p> <p><a name="Retinoblastoma" id="Retinoblastoma"></a></p> <h3><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&action=edit§ion=2" title="Edit section: Retinoblastoma">edit</a>]</span> <span class="mw-headline">Retinoblastoma</span></h3> <p>The classical example of such a loss of protecting genes is hereditary <a href="http://en.wikipedia.org/wiki/Retinoblastoma" title="Retinoblastoma">retinoblastoma</a>, in which one parent's contribution of the tumor suppressor Rb1 is flawed. Although most cells will have a functional second copy, chance loss of heterozygosity events in individual cells almost invariably lead to the development of this retinal cancer in the young child.</p> <p><a name="Detection" id="Detection"></a></p> <h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&action=edit§ion=3" title="Edit section: Detection">edit</a>]</span> <span class="mw-headline">Detection</span></h2> <p>Loss of heterozygosity can be identified in cancers by noting the presence of <a href="http://en.wikipedia.org/wiki/Heterozygosity" title="Heterozygosity">heterozygosity</a> at a genetic <a href="http://en.wikipedia.org/wiki/Locus_%28genetics%29" title="Locus (genetics)">locus</a> in an organism's <a href="http://en.wikipedia.org/wiki/Germline" title="Germline">germline</a> <a href="http://en.wikipedia.org/wiki/DNA" title="DNA">DNA</a>, and the absence of heterozygosity at that locus in the cancer cells. This is often done using <a href="http://en.wikipedia.org/wiki/Polymorphism_%28biology%29" title="Polymorphism (biology)">polymorphic</a> markers, such as <a href="http://en.wikipedia.org/wiki/Microsatellites" title="Microsatellites">microsatellites</a> or <a href="http://en.wikipedia.org/wiki/Single_nucleotide_polymorphisms" title="Single nucleotide polymorphisms">single nucleotide polymorphisms</a>, for which the two parents contributed different <a href="http://en.wikipedia.org/wiki/Alleles" title="Alleles">alleles</a>.</p> <p><a name="See_also" id="See_also"></a></p> <h2><span class="editsection">[<a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&action=edit§ion=4" title="Edit section: See also">edit</a>]</span> <span class="mw-headline">See also</span></h2> <ul><li><a href="http://en.wikipedia.org/wiki/Tumor_suppressor_gene" title="Tumor suppressor gene">Tumor suppressor gene</a></li><li><a href="http://en.wikipedia.org/w/index.php?title=Loss_of_imprinting&action=edit" class="new" title="Loss of imprinting">Loss of imprinting</a></li></ul> <!-- Saved in parser cache with key enwiki:pcache:idhash:1790681-0!1!0!default!!en!2 and timestamp 20070820212507 --> <div class="printfooter"> Retrieved from "<a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity">http://en.wikipedia.org/wiki/Loss_of_heterozygosity</a>"</div> <div id="catlinks"><p class="catlinks"><a href="http://en.wikipedia.org/wiki/Special:Categories" title="Special:Categories">Category</a>: <span dir="ltr"><a href="http://en.wikipedia.org/wiki/Category:Mutation" title="Category:Mutation">Mutation</a></span></p></div> <!-- end content --> </div> </div> </div> <div id="column-one"> <div id="p-cactions" class="portlet"> <h5>Views</h5> <div class="pBody"> <ul><li id="ca-nstab-main" class="selected"><a href="http://en.wikipedia.org/wiki/Loss_of_heterozygosity" title="View the content page [alt-shift-c]" accesskey="c">Article</a></li><li id="ca-talk" class="new"><a href="http://en.wikipedia.org/w/index.php?title=Talk:Loss_of_heterozygosity&action=edit" title="Discussion about the content page [alt-shift-t]" accesskey="t">Discussion</a></li><li id="ca-edit"><a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&action=edit" title="You can edit this page. Please use the preview button before saving. [alt-shift-e]" accesskey="e">Edit this page</a></li><li id="ca-history"><a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&action=history" title="Past versions of this page [alt-shift-h]" accesskey="h">History</a></li></ul> </div> </div> <div class="portlet" id="p-personal"> <h5>Personal tools</h5> <div class="pBody"> <ul><li id="pt-login"><a href="http://en.wikipedia.org/w/index.php?title=Special:Userlogin&returnto=Loss_of_heterozygosity" title="You are encouraged to log in, it is not mandatory however. [alt-shift-o]" accesskey="o">Sign in / create account</a></li></ul> </div> </div> <div class="portlet" id="p-logo"> </div> <script type="text/javascript"> if (window.isMSIE55) fixalpha(); </script> <div class="portlet" id="p-navigation"> <h5>Navigation</h5> <div class="pBody"> <ul><li id="n-Main-page"><a title="Visit the main page [alt-shift-z]" accesskey="z" href="http://en.wikipedia.org/wiki/Main_Page">Main page</a></li><li title="Guides to browsing Wikipedia" id="n-Contents"><a href="http://en.wikipedia.org/wiki/Wikipedia:Contents">Contents</a></li><li title="Featured content — the best of Wikipedia" id="n-Featured-content"><a href="http://en.wikipedia.org/wiki/Wikipedia:Featured_content">Featured content</a></li><li id="n-currentevents"><a href="http://en.wikipedia.org/wiki/Portal:Current_events" title="Find background information on current events">Current events</a></li><li id="n-randompage"><a href="http://en.wikipedia.org/wiki/Special:Random" title="Load a random page [alt-shift-x]" accesskey="x">Random article</a></li></ul> </div> </div> <div class="portlet" id="p-interaction"> <h5>interaction</h5> <div class="pBody"> <ul><li id="n-About-Wikipedia"><a href="http://en.wikipedia.org/wiki/Wikipedia:About">About Wikipedia</a></li><li id="n-portal"><a href="http://en.wikipedia.org/wiki/Wikipedia:Community_Portal" title="About the project, what you can do, where to find things">Community portal</a></li><li id="n-recentchanges"><a href="http://en.wikipedia.org/wiki/Special:Recentchanges" title="The list of recent changes in the wiki [alt-shift-r]" accesskey="r">Recent changes</a></li><li title="How to contact Wikipedia" id="n-contact"><a href="http://en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li><li title="Help keep Wikipedia running" id="n-sitesupport"><a href="http://wikimediafoundation.org/wiki/Fundraising" title="Support us">Donate to Wikipedia</a></li><li title="The place to find out about Wikipedia" id="n-help"><a href="http://en.wikipedia.org/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia">Help</a></li></ul> </div> </div> <div id="p-search" class="portlet"> <h5><label for="searchInput">Search</label></h5> <div id="searchBody" class="pBody"> <form action="/wiki/Special:Search" id="searchform"><div> <input id="searchInput" name="search" title="Search Wikipedia [alt-shift-f]" accesskey="f" value="" type="text"> <input name="go" class="searchButton" id="searchGoButton" value="Go" type="submit"> <input name="fulltext" class="searchButton" id="mw-searchButton" value="Search" type="submit"> </div></form> </div> </div> <div class="portlet" id="p-tb"> <h5>Toolbox</h5> <div class="pBody"> <ul><li id="t-whatlinkshere"><a href="http://en.wikipedia.org/wiki/Special:Whatlinkshere/Loss_of_heterozygosity" title="List of all wiki pages that link here [alt-shift-j]" accesskey="j">What links here</a></li><li id="t-recentchangeslinked"><a href="http://en.wikipedia.org/wiki/Special:Recentchangeslinked/Loss_of_heterozygosity" title="Recent changes in pages linked from this page [alt-shift-k]" accesskey="k">Related changes</a></li><li id="t-upload"><a href="http://en.wikipedia.org/wiki/Wikipedia:Upload" title="Upload images or media files [alt-shift-u]" accesskey="u">Upload file</a></li><li id="t-specialpages"><a href="http://en.wikipedia.org/wiki/Special:Specialpages" title="List of all special pages [alt-shift-q]" accesskey="q">Special pages</a></li><li title="Printable version of this page" id="t-print"><a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&printable=yes" title="Printable version of this page [alt-shift-p]" accesskey="p">Printable version</a></li><li title="Permanent link to this version of the page" id="t-permalink"><a href="http://en.wikipedia.org/w/index.php?title=Loss_of_heterozygosity&oldid=148749373" title="Permanent link to this version of the page">Permanent link</a></li><li title="Cite this Wikipedia article" id="t-cite"><a href="http://en.wikipedia.org/w/index.php?title=Special:Cite&page=Loss_of_heterozygosity&id=148749373">Cite this article</a></li></ul> </div> </div> <div id="p-lang" class="portlet"> <h5>In other languages</h5> <div class="pBody"> <ul><li class="interwiki-fr"><a href="http://fr.wikipedia.org/wiki/Perte_d%E2%80%99h%C3%A9t%C3%A9rozygotie">Français</a></li></ul> </div> </div> </div><!-- end of the left (by default at least) column --> <div id="footer"> <div id="f-poweredbyico"><a href="http://www.mediawiki.org/"><img src="http://en.wikipedia.org/skins-1.5/common/images/poweredby_mediawiki_88x31.png" alt="Powered by MediaWiki" /></a></div> <div id="f-copyrightico"><a href="http://wikimediafoundation.org/"><img src="http://en.wikipedia.org/images/wikimedia-button.png" alt="Wikimedia Foundation" border="0" /></a></div> <ul id="f-list"><li id="lastmod"> This page was last modified 16:49, 2 August 2007.</li><li id="copyright">All text is available under the terms of the <a class="internal" href="http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License" title="Wikipedia:Text of the GNU Free Documentation License">GNU Free Documentation License</a>. (See <b><a class="internal" href="http://en.wikipedia.org/wiki/Wikipedia:Copyrights" title="Wikipedia:Copyrights">Copyrights</a></b> for details.)<br />Wikipedia® is a registered trademark of the <a href="http://www.wikimediafoundation.org/">Wikimedia Foundation, Inc</a>., a US-registered <a class="internal" href="http://en.wikipedia.org/wiki/501%28c%29#501.28c.29.283.29" title="501(c)(3)">501(c)(3)</a> <a href="http://wikimediafoundation.org/wiki/Deductibility_of_donations">tax-deductible</a> <a class="internal" href="http://en.wikipedia.org/wiki/Non-profit_organization" title="Non-profit organization">nonprofit</a> <a href="http://en.wikipedia.org/wiki/Charitable_organization" title="Charitable organization">charity</a>.<br /></li><li id="privacy"><a href="http://wikimediafoundation.org/wiki/Privacy_policy" title="wikimedia:Privacy policy">Privacy policy</a></li><li id="about"><a href="http://en.wikipedia.org/wiki/Wikipedia:About" title="Wikipedia:About">About Wikipedia</a></li><li id="disclaimer"><a href="http://en.wikipedia.org/wiki/Wikipedia:General_disclaimer" title="Wikipedia:General disclaimer">Disclaimers</a></li></ul> </div> <script type="text/javascript">if (window.runOnloadHook) runOnloadHook();</script><div style="position: absolute; z-index: 40; left: 155px; top: 0px; clear: both; float: left;" id="donate"> <div style="font-size: 80%;"><i>Your <a href="http://wikimediafoundation.org/wiki/Fundraising" class="extiw" title="wikimedia:Fundraising">continued donations</a> keep Wikipedia running!</i> </div></div> </div> <!-- Served by srv124 in 0.067 secs. -->potstubhttp://www.blogger.com/profile/01645040450324992818noreply@blogger.com0