Difference between revisions of "What is a C. elegans?"

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<p><em><strong>Caenorhabditis elegans</strong></em> (pronounced <span title="Pronunciation in the International Phonetic Alphabet (IPA)" class="IPA"><a href="/wiki/Wikipedia:IPA_for_English" title="Wikipedia:IPA for English">/ˌsiːnoʊr&aelig;bˈdaɪt<s>ɪ</s>s ˈɛl<s>ɪ</s>g&aelig;nz/</a></span>) is a free-living, transparent <a href="/wiki/Nematode" title="Nematode">nematode</a> (roundworm), about 1&nbsp;mm in length, which lives in temperate soil environments. Research into the <a href="/wiki/Molecular_biology" title="Molecular biology">molecular</a> and <a href="/wiki/Developmental_biology" title="Developmental biology">developmental biology</a> of <em>C. elegans</em> was begun in 1974 by <a href="/wiki/Sydney_Brenner" title="Sydney Brenner">Sydney Brenner</a> and it has since been used extensively as a <a href="/wiki/Model_organism" title="Model organism">model organism</a>.<sup id="cite_ref-0" class="reference"><a href="#cite_note-0" title=""><span>[</span>1<span>]</span></a></sup></p>
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<p><font color="#000000"><em><strong>Caenorhabditis elegans</strong></em> (pronounced <span class="IPA" title="Pronunciation in the International Phonetic Alphabet (IPA)">/ˌsiːnoʊr&aelig;bˈdaɪt<s>ɪ</s>s ˈɛl<s>ɪ</s>g&aelig;nz/</span>) is a free-living, transparent nematode (roundworm), about 1&nbsp;mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of <em>C. elegans</em> was begun in 1974 by Sydney Brenner and it has since been used extensively as a model organism.<sup class="reference" id="cite_ref-0"><span>[</span>1<span>]</span></sup></font></p>
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<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Biology</font></span></h2>
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Movement of Wild-type <em>C. elegans</em></div>
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<font color="#000000">Movement of Wild-type <em>C. elegans</em></font></div>
 
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<p><em>C. elegans</em> is <a href="/wiki/Segmentation_(biology)" title="Segmentation (biology)">unsegmented</a>, <a href="http://en.wiktionary.org/wiki/vermiform" title="wikt:vermiform" class="extiw">vermiform</a>, <a href="/wiki/Symmetry_(biology)#Bilateral_symmetry" title="Symmetry (biology)">bilaterally symmetrical</a>, with a <a href="/wiki/Cuticle" title="Cuticle">cuticle</a> integument, four main epidermal cords and a fluid-filled <a href="/wiki/Pseudocoelom" title="Pseudocoelom" class="mw-redirect">pseudocoelomate</a> cavity. Members of the species have many of the same organ systems as other animals. In the wild, they feed on bacteria that develop on decaying vegetable matter. Individuals of <em>C. elegans</em> are almost all <a href="/wiki/Hermaphrodite" title="Hermaphrodite">hermaphrodite</a>, with males comprising just 0.05% of the total population on average. The basic anatomy of <em>C. elegans</em> includes a mouth, <a href="/wiki/Pharynx" title="Pharynx">pharynx</a>, intestine, <a href="/wiki/Gonad" title="Gonad">gonad</a>, and collagenous cuticle. Males have a single-lobed gonad, <a href="/wiki/Vas_deferens" title="Vas deferens">vas deferens</a>, and a tail specialized for mating. Hermaphrodites have two ovaries, oviducts, spermatheca, and a single uterus.</p>
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<p><font color="#000000"><em>C. elegans</em> is unsegmented, vermiform, bilaterally symmetrical, with a cuticle integument, four main epidermal cords and a fluid-filled pseudocoelomate cavity. Members of the species have many of the same organ systems as other animals. In the wild, they feed on bacteria that develop on decaying vegetable matter. Individuals of <em>C. elegans</em> are almost all hermaphrodite, with males comprising just 0.05% of the total population on average. The basic anatomy of <em>C. elegans</em> includes a mouth, pharynx, intestine, gonad, and collagenous cuticle. Males have a single-lobed gonad, vas deferens, and a tail specialized for mating. Hermaphrodites have two ovaries, oviducts, spermatheca, and a single uterus.</font></p>
<p><em>C. elegans</em> eggs are laid by the hermaphrodite. After hatching, they pass through four <a href="/wiki/Larva" title="Larva">larval</a> stages (L1-L4). When crowded or in the absence of food, <em>C. elegans</em> can enter an alternative third larval stage called the <a href="/wiki/Dauer_larva" title="Dauer larva">dauer</a> state. Dauer larvae are stress-resistant and do not age. Hermaphrodites produce all their sperm in the L4 stage (150 sperm per gonadal arm) and then switch over to producing oocytes. The sperm are stored in the same area of the gonad as the oocytes until the first oocyte pushes the sperm into the spermatheca (a kind of chamber where the oocytes become fertilized by the sperm).<sup id="cite_ref-1" class="reference"><a href="#cite_note-1" title=""><span>[</span>2<span>]</span></a></sup> The male can inseminate the hermaphrodite, which will use male sperm preferentially (both types of sperm are stored in the spermatheca). When self-inseminated the wild-type worm will lay approximately 300 eggs. When inseminated by a male, the number of progeny can exceed 1,000. At 20<a href="/wiki/Celsius" title="Celsius">&deg;C</a>, the laboratory strain of <em>C. elegans</em> has an average life span of approximately 2&ndash;3 weeks and a generation time of approximately 4 days. Hermaphrodites can mate with males or self-fertilize.</p>
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<p><font color="#000000"><em>C. elegans</em> eggs are laid by the hermaphrodite. After hatching, they pass through four larval stages (L1-L4). When crowded or in the absence of food, <em>C. elegans</em> can enter an alternative third larval stage called the dauer state. Dauer larvae are stress-resistant and do not age. Hermaphrodites produce all their sperm in the L4 stage (150 sperm per gonadal arm) and then switch over to producing oocytes. The sperm are stored in the same area of the gonad as the oocytes until the first oocyte pushes the sperm into the spermatheca (a kind of chamber where the oocytes become fertilized by the sperm).<sup class="reference" id="cite_ref-1"><span>[</span>2<span>]</span></sup> The male can inseminate the hermaphrodite, which will use male sperm preferentially (both types of sperm are stored in the spermatheca). When self-inseminated the wild-type worm will lay approximately 300 eggs. When inseminated by a male, the number of progeny can exceed 1,000. At 20&deg;C, the laboratory strain of <em>C. elegans</em> has an average life span of approximately 2&ndash;3 weeks and a generation time of approximately 4 days. Hermaphrodites can mate with males or self-fertilize.</font></p>
<p><em>C. elegans</em> has five pairs of <a href="/wiki/Autosome" title="Autosome">autosomes</a> and one pair of <a href="/wiki/Sex_chromosome" title="Sex chromosome" class="mw-redirect">sex chromosomes</a>. Sex in <em>C. elegans</em> is based on an <a href="/wiki/X0_sex-determination_system" title="X0 sex-determination system">X0 sex-determination system</a>. Hermaphrodite <em>C. elegans</em> have a matched pair of sex chromosomes (XX); the rare males have only one sex chromosome (X0).</p>
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<p><font color="#000000"><em>C. elegans</em> has five pairs of autosomes and one pair of sex chromosomes. Sex in <em>C. elegans</em> is based on an X0 sex-determination system. Hermaphrodite <em>C. elegans</em> have a matched pair of sex chromosomes (XX); the rare males have only one sex chromosome (X0).</font></p>
<p>It is interesting to note that <em>C. elegans</em> is one of the only forms of life not known to have a natural virus.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2" title=""><span>[</span>3<span>]</span></a></sup></p>
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<p><font color="#000000">It is interesting to note that <em>C. elegans</em> is one of the only forms of life not known to have a natural virus.<sup class="reference" id="cite_ref-2"><span>[</span>3<span>]</span></sup></font></p>
 
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Longitudinal section through the hermaphrodite <em>C. elegans.</em></div>
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<font color="#000000">Longitudinal section through the hermaphrodite <em>C. elegans.</em></font></div>
 
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<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Laboratory uses</font></span></h2>
<p><em>C. elegans</em> is studied as a <a href="/wiki/Model_organism" title="Model organism">model organism</a> for a variety of reasons. <a href="/wiki/Strain_(biology)" title="Strain (biology)">Strains</a> are cheap to breed and can be frozen. When subsequently thawed they remain viable, allowing long-term storage. Because the complete cell lineage of the species has been determined, <em>C. elegans</em> has proven especially useful for studying <a href="/wiki/Cellular_differentiation" title="Cellular differentiation">cellular differentiation</a>.</p>
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<p><font color="#000000"><em>C. elegans</em> is studied as a model organism for a variety of reasons. Strains are cheap to breed and can be frozen. When subsequently thawed they remain viable, allowing long-term storage. Because the complete cell lineage of the species has been determined, <em>C. elegans</em> has proven especially useful for studying cellular differentiation.</font></p>
<p>From a research perspective, <em>C. elegans</em> has the advantage of being a <a href="/wiki/Multicellular" title="Multicellular" class="mw-redirect">multicellular</a> <a href="/wiki/Eukaryote" title="Eukaryote">eukaryotic</a> organism that is simple enough to be studied in great detail. In addition, it is transparent facilitating the study of developmental processes in the intact organism. The developmental fate of every single <a href="/wiki/Somatic_cell" title="Somatic cell">somatic cell</a>  (959 in the adult hermaphrodite; 1031 in the adult male) has been mapped out. These patterns of cell lineage are largely invariant between individuals, in contrast to mammals where cell development from the embryo is more largely dependent on cellular cues. In both sexes, a large number of additional cells (131 in the hermaphrodite, most of which would otherwise become <a href="/wiki/Neuron" title="Neuron">neurons</a>), are eliminated by programmed cell death (<a href="/wiki/Apoptosis" title="Apoptosis">apoptosis</a>).</p>
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<p><font color="#000000">From a research perspective, <em>C. elegans</em> has the advantage of being a multicellular eukaryotic organism that is simple enough to be studied in great detail. In addition, it is transparent facilitating the study of developmental processes in the intact organism. The developmental fate of every single somatic cell (959 in the adult hermaphrodite; 1031 in the adult male) has been mapped out. These patterns of cell lineage are largely invariant between individuals, in contrast to mammals where cell development from the embryo is more largely dependent on cellular cues. In both sexes, a large number of additional cells (131 in the hermaphrodite, most of which would otherwise become neurons), are eliminated by programmed cell death (apoptosis).</font></p>
 
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Wild-type <em>C. elegans</em> hermaphrodite stained to highlight the nuclei of all cells</div>
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<font color="#000000">Wild-type <em>C. elegans</em> hermaphrodite stained to highlight the nuclei of all cells</font></div>
 
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<p>In addition, <em>C. elegans</em> is one of the simplest organisms with a <a href="/wiki/Nervous_system" title="Nervous system">nervous system</a>. In the hermaphrodite, this comprises 302 <a href="/wiki/Neuron" title="Neuron">neurons</a> whose pattern of connectivity has been completely mapped out, and shown to be a <a href="/wiki/Small-world_network" title="Small-world network">small-world network</a>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3" title=""><span>[</span>4<span>]</span></a></sup> Research has explored the neural mechanisms responsible for several of the more interesting behaviors shown by <em>C. elegans</em>, including <a href="/wiki/Chemotaxis" title="Chemotaxis">chemotaxis</a>, <a href="/wiki/Thermotaxis" title="Thermotaxis">thermotaxis</a>, <a href="/wiki/Mechanotransduction" title="Mechanotransduction">mechanotransduction</a>, and male mating  behavior.</p>
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<p><font color="#000000">In addition, <em>C. elegans</em> is one of the simplest organisms with a nervous system. In the hermaphrodite, this comprises 302 neurons whose pattern of connectivity has been completely mapped out, and shown to be a small-world network.<sup class="reference" id="cite_ref-3"><span>[</span>4<span>]</span></sup> Research has explored the neural mechanisms responsible for several of the more interesting behaviors shown by <em>C. elegans</em>, including chemotaxis, thermotaxis, mechanotransduction, and male mating behavior.</font></p>
<p>A useful feature of <em>C. elegans</em> is that it is relatively straightforward to disrupt the function of specific genes by <a href="/wiki/RNA_interference" title="RNA interference">RNA interference</a>  (RNAi). <a href="/wiki/Gene_silencing" title="Gene silencing">Silencing</a> the function of a gene in this way can sometimes allow a researcher to infer what the function of that gene may be. The nematode can either be soaked in (or injected with) a solution of double stranded <a href="/wiki/RNA" title="RNA">RNA</a>, the sequence of which is complementary to the sequence of the gene that the researcher wishes to disable. Alternatively, worms can be fed on genetically transformed <a href="/wiki/Bacteria" title="Bacteria">bacteria</a> which <a href="/wiki/Gene_expression" title="Gene expression">express</a> the double stranded RNA of  interest.</p>
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<p><font color="#000000">A useful feature of <em>C. elegans</em> is that it is relatively straightforward to disrupt the function of specific genes by RNA interference (RNAi). Silencing the function of a gene in this way can sometimes allow a researcher to infer what the function of that gene may be. The nematode can either be soaked in (or injected with) a solution of double stranded RNA, the sequence of which is complementary to the sequence of the gene that the researcher wishes to disable. Alternatively, worms can be fed on genetically transformed bacteria which express the double stranded RNA of interest.</font></p>
<p><em>C. elegans</em> has also been useful in the study of <a href="/wiki/Meiosis" title="Meiosis">meiosis</a>. As sperm and egg nuclei move down the length of the gonad, they undergo a temporal progression through meiotic events. This progression means that every nucleus at a given position in the gonad will be at roughly the same step in meiosis, eliminating the difficulties of heterogeneous populations of cells.</p>
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<p><font color="#000000"><em>C. elegans</em> has also been useful in the study of meiosis. As sperm and egg nuclei move down the length of the gonad, they undergo a temporal progression through meiotic events. This progression means that every nucleus at a given position in the gonad will be at roughly the same step in meiosis, eliminating the difficulties of heterogeneous populations of cells.</font></p>
<p>The organism has also been identified as a model for <a href="/wiki/Nicotine" title="Nicotine">nicotine</a> dependence as it has been found to experience the same symptoms humans experience when they <a href="/wiki/Smoking_cessation" title="Smoking cessation">quit smoking</a>.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4" title=""><span>[</span>5<span>]</span></a></sup></p>
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<p><font color="#000000">The organism has also been identified as a model for nicotine dependence as it has been found to experience the same symptoms humans experience when they quit smoking.<sup class="reference" id="cite_ref-4"><span>[</span>5<span>]</span></sup></font></p>
<p>As for most model organisms, there is a dedicated online database for the species that is actively curated by scientists working in this field. The <a href="/wiki/Wormbase" title="Wormbase">WormBase</a> database attempts to collate all published information on <em>C. elegans</em> and other related nematodes. A reward of $5000 has been advertised on their website, for the finder of a new species of closely related nematode.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5" title=""><span>[</span>6<span>]</span></a></sup> Such a discovery would broaden research opportunities with the worm.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6" title=""><span>[</span>7<span>]</span></a></sup></p>
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<p><font color="#000000">As for most model organisms, there is a dedicated online database for the species that is actively curated by scientists working in this field. The WormBase database attempts to collate all published information on <em>C. elegans</em> and other related nematodes. A reward of $5000 has been advertised on their website, for the finder of a new species of closely related nematode.<sup class="reference" id="cite_ref-5"><span>[</span>6<span>]</span></sup> Such a discovery would broaden research opportunities with the worm.<sup class="reference" id="cite_ref-6"><span>[</span>7<span>]</span></sup></font></p>
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<h2><span class="mw-headline"><font color="#000000">C. elegans Genome and [[C. elegans Genomics]]</font></span></h2>
<p><em>C. elegans</em> was the first multicellular organism to have its <a href="/wiki/Genome" title="Genome">genome</a> completely <a href="/wiki/Sequencing" title="Sequencing">sequenced</a>. The finished genome sequence was published in 1998,<sup id="cite_ref-7" class="reference"><a href="#cite_note-7" title=""><span>[</span>8<span>]</span></a></sup> although a number of small gaps were present (the last gap was finished by October 2002). The <em>C. elegans</em> genome sequence is approximately 100 million <a href="/wiki/Base_pair" title="Base pair">base pairs</a> long and contains approximately 20,000 <a href="/wiki/Gene" title="Gene">genes</a>. The vast majority of these genes encode for <a href="/wiki/Protein" title="Protein">proteins</a> but there are likely to be as many as 1,000 <a href="/wiki/RNA_gene" title="RNA gene" class="mw-redirect">RNA genes</a>. Scientific curators continue to appraise the set of known genes, such that new gene predictions continue to be added and incorrect ones modified or removed.</p>
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<p><font color="#000000"><strong><em>C. elegans</em> was the first multicellular organism to have its genome completely sequenced</strong>.&nbsp;<br />
<p>In 2003, the genome sequence of the related nematode <em><a href="/wiki/Caenorhabditis_briggsae" title="Caenorhabditis briggsae">C. briggsae</a></em> was also determined, allowing researchers to study the comparative genomics of these two organisms.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8" title=""><span>[</span>9<span>]</span></a></sup> Work is now ongoing to determine the genome sequences of more nematodes from the same <a href="/wiki/Genus" title="Genus">genus</a> such as <em>C. remanei</em>,<sup id="cite_ref-9" class="reference"><a href="#cite_note-9" title=""><span>[</span>10<span>]</span></a></sup> <em>C. japonica</em><sup id="cite_ref-10" class="reference"><a href="#cite_note-10" title=""><span>[</span>11<span>]</span></a></sup> and <em>C. brenneri</em>.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11" title=""><span>[</span>12<span>]</span></a></sup> These newer genome sequences are being determined by using the <a href="/wiki/Whole_genome_shotgun" title="Whole genome shotgun" class="mw-redirect">whole genome  shotgun</a> technique which means that the resulting genome sequences are likely to not be as complete or accurate as <em>C. elegans</em> (which was sequenced using the 'hierarchical' or <a href="/wiki/Clone_(genetics)" title="Clone (genetics)" class="mw-redirect">clone</a>-by-clone approach).</p>
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The finished genome sequence was published in 1998,<sup class="reference" id="cite_ref-7"><span>[</span>8<span>]</span></sup> although a number of small gaps were present (the last gap was finished by October 2002). The <em>C. elegans</em> genome sequence is approximately 100 million base pairs long and contains approximately <strong>20,000</strong> genes. The vast majority of these genes encode for proteins but there are likely to be as many as 1,000 RNA genes. Scientific curators continue to appraise the set of known genes, such that new gene predictions continue to be added and incorrect ones modified or removed.</font></p>
<p>The official version of the <em>C. elegans</em> genome sequence continues to change as and when new evidence reveals errors in the original sequencing (<a href="/wiki/DNA_sequencing" title="DNA sequencing">DNA sequencing</a> is not an error-free process). Most changes are minor, adding or removing only a few <a href="/wiki/Base_pair" title="Base pair">base pairs</a> (bp) of DNA. E.g. the WS169 release of <a rel="nofollow" href="http://www.wormbase.org/" title="http://www.wormbase.org" class="external text">WormBase</a> (December 2006) lists a net gain of 6 bp to the genome sequence.<sup id="cite_ref-WS169_12-0" class="reference"><a href="#cite_note-WS169-12" title=""><span>[</span>13<span>]</span></a></sup> Occasionally more extensive changes are made, e.g. the WS159 release of May 2006 added over 300 bp to the sequence.<sup id="cite_ref-WS159_13-0" class="reference"><a href="#cite_note-WS159-13" title=""><span>[</span>14<span>]</span></a></sup></p>
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<p><font color="#000000">In 2003, the genome sequence of the related nematode <em>C. briggsae</em> was also determined, allowing researchers to study the comparative genomics of these two organisms.<sup class="reference" id="cite_ref-8"><span>[</span>9<span>]</span></sup> Work is now ongoing to determine the genome sequences of more nematodes from the same genus such as <em>C. remanei</em>,<sup class="reference" id="cite_ref-9"><span>[</span>10<span>]</span></sup> <em>C. japonica</em><sup class="reference" id="cite_ref-10"><span>[</span>11<span>]</span></sup> and <em>C. brenneri</em>.<sup class="reference" id="cite_ref-11"><span>[</span>12<span>]</span></sup> These newer genome sequences are being determined by using the whole genome shotgun technique which means that the resulting genome sequences are likely to not be as complete or accurate as <em>C. elegans</em> (which was sequenced using the 'hierarchical' or clone-by-clone approach).</font></p>
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<p><font color="#000000">The official version of the <em>C. elegans</em> genome sequence continues to change as and when new evidence reveals errors in the original sequencing (DNA sequencing is not an error-free process). Most changes are minor, adding or removing only a few base pairs (bp) of DNA. E.g. the WS169 release of WormBase (December 2006) lists a net gain of 6 bp to the genome sequence.<sup class="reference" id="cite_ref-WS169_12-0"><span>[</span>13<span>]</span></sup> Occasionally more extensive changes are made, e.g. the WS159 release of May 2006 added over 300 bp to the sequence.<sup class="reference" id="cite_ref-WS159_13-0"><span>[</span>14<span>]</span></sup></font></p>
<h2><span class="editsection"></span><span class="mw-headline">Evolution</span></h2>
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<p><font color="#000000"></font></p>
<p>It has been shown that a small number of conserved <a href="/wiki/Protein" title="Protein">protein</a> sequences from <a href="/wiki/Sea_sponge" title="Sea sponge" class="mw-redirect">sponges</a> are more similar to  humans than to <em>C. elegans</em>.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14" title=""><span>[</span>15<span>]</span></a></sup> This suggests that there has been an accelerated rate of evolution in the <em>C. elegans</em> <a href="/wiki/Lineage_(evolution)" title="Lineage (evolution)">lineage</a>. The  same study found that several <a href="/wiki/Phylogenetically" title="Phylogenetically" class="mw-redirect">phylogenetically</a> ancient genes are not present  in <em>C. elegans</em>.</p>
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<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Evolution</font></span></h2>
<p><a name="Scientific_community" id="Scientific_community"></a></p>
+
<p><font color="#000000">It has been shown that a small number of conserved protein sequences from sponges are more similar to humans than to <em>C. elegans</em>.<sup class="reference" id="cite_ref-14"><span>[</span>15<span>]</span></sup> This suggests that there has been an accelerated rate of evolution in the <em>C. elegans</em> lineage. The same study found that several phylogenetically ancient genes are not present in <em>C. elegans</em>.</font></p>
<h2><span class="editsection"></span><span class="mw-headline">Scientific community</span></h2>
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<p><font color="#000000"></font></p>
<p>In 2002, the <a href="/wiki/Nobel_Prize_in_Physiology_or_Medicine" title="Nobel Prize in Physiology or Medicine">Nobel Prize in Physiology or  Medicine</a> was awarded to <a href="/wiki/Sydney_Brenner" title="Sydney Brenner">Sydney Brenner</a>, <a href="/wiki/H._Robert_Horvitz" title="H. Robert Horvitz">H. Robert Horvitz</a> and <a href="/wiki/John_Sulston" title="John Sulston" class="mw-redirect">John Sulston</a> for their work  on the genetics of organ development and <a href="/wiki/Apoptosis" title="Apoptosis">programmed cell death</a> (PCD) in <em>C. elegans</em>. The  2006 <a href="/wiki/Nobel_Prize_in_Physiology_or_Medicine" title="Nobel Prize in Physiology or Medicine">Nobel Prize in Physiology or  Medicine</a> was awarded to <a href="/wiki/Andrew_Fire" title="Andrew Fire">Andrew Fire</a> and <a href="/wiki/Craig_C._Mello" title="Craig C. Mello" class="mw-redirect">Craig C. Mello</a>, for their  discovery of <a href="/wiki/RNA_interference" title="RNA interference">RNA  interference</a> in <em>C. elegans</em>.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15" title=""><span>[</span>16<span>]</span></a></sup>. In 2008  <a href="/wiki/Martin_Chalfie" title="Martin Chalfie">Martin Chalfie</a> shared  a <a href="/wiki/Nobel_Prize_in_Chemistry" title="Nobel Prize in Chemistry">Nobel Prize in Chemistry</a> for his work  on <a href="/wiki/Green_fluorescent_protein" title="Green fluorescent protein">green fluorescent protein</a> (GFP) in  <em>C. elegans</em>.</p>
+
<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Scientific community</font></span></h2>
<p>Because all research into <em>C. elegans</em> essentially started with <a href="/wiki/Sydney_Brenner" title="Sydney Brenner">Sydney Brenner</a> in the 1970s, many scientists working in this field share a close connection to Brenner  (they either worked as a <a href="/wiki/Post-doctoral" title="Post-doctoral" class="mw-redirect">post-doctoral</a> or <a href="/wiki/Post-graduate" title="Post-graduate" class="mw-redirect">post-graduate</a> researcher in  Brenner's lab or in the lab of someone who previously worked with Brenner).  Because most people who worked in his lab went on to establish their own worm  research labs, there is now a fairly well documented 'lineage' of <em>C.  elegans</em> scientists. This lineage was recorded in some detail at the 2003  International Worm Meeting and the results were stored in the <a href="/wiki/Wormbase" title="Wormbase">Wormbase</a> database.</p>
+
<p><font color="#000000">In 2002, the Nobel Prize in Physiology or Medicine was awarded to Sydney Brenner, H. Robert Horvitz and John Sulston for their work on the genetics of organ development and programmed cell death (PCD) in <em>C. elegans</em>. The 2006 Nobel Prize in Physiology or Medicine was awarded to Andrew Fire and Craig C. Mello, for their discovery of RNA interference in <em>C. elegans</em>.<sup class="reference" id="cite_ref-15"><span>[</span>16<span>]</span></sup>. In 2008 Martin Chalfie shared a Nobel Prize in Chemistry for his work on green fluorescent protein (GFP) in <em>C. elegans</em>.</font></p>
<p><a name="In_the_media" id="In_the_media"></a></p>
+
<p><font color="#000000">Because all research into <em>C. elegans</em> essentially started with Sydney Brenner in the 1970s, many scientists working in this field share a close connection to Brenner (they either worked as a post-doctoral or post-graduate researcher in Brenner's lab or in the lab of someone who previously worked with Brenner). Because most people who worked in his lab went on to establish their own worm research labs, there is now a fairly well documented 'lineage' of <em>C. elegans</em> scientists. This lineage was recorded in some detail at the 2003 International Worm Meeting and the results were stored in the Wormbase database.</font></p>
<h2><span class="editsection"></span><span class="mw-headline">In the media</span></h2>
+
<p><font color="#000000"></font></p>
<p><em>C. elegans</em> made news when it was discovered that specimens had  survived the <a href="/wiki/Space_Shuttle_Columbia_disaster" title="Space Shuttle Columbia disaster">Space Shuttle <em>Columbia</em>  disaster</a> in February 2003.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16" title=""><span>[</span>17<span>]</span></a></sup> Later, in January  2009, it was announced that live samples of C.elegans from the <a href="/wiki/University_of_Nottingham" title="University of Nottingham">University of Nottingham</a> will spend  two weeks on the <a href="/wiki/International_Space_Station" title="International Space Station">International Space Station</a> as part  of a project to explore the effects of <a href="/wiki/Zero_gravity" title="Zero gravity" class="mw-redirect">zero gravity</a> on muscle development and its  physiology. The emphasis of the research will be on the genetic basis of <a href="/wiki/Muscle_atrophy" title="Muscle atrophy">muscle atrophy</a>. This has  relevance to space travel, but also to individuals who are bed-ridden, <a href="/wiki/Geriatric" title="Geriatric" class="mw-redirect">geriatric</a> or <a href="/wiki/Diabetic" title="Diabetic" class="mw-redirect">diabetic</a>.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17" title=""><span>[</span>18<span>]</span></a></sup></p>
+
<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>In the media</font></span></h2>
<p><a name="See_also" id="See_also"></a></p>
+
<p><font color="#000000"><em>C. elegans</em> made news when it was discovered that specimens had survived the Space Shuttle <em>Columbia</em> disaster in February 2003.<sup class="reference" id="cite_ref-16"><span>[</span>17<span>]</span></sup> Later, in January 2009, it was announced that live samples of C.elegans from the University of Nottingham will spend two weeks on the International Space Station as part of a project to explore the effects of zero gravity on muscle development and its physiology. The emphasis of the research will be on the genetic basis of muscle atrophy. This has relevance to space travel, but also to individuals who are bed-ridden, geriatric or diabetic.<sup class="reference" id="cite_ref-17"><span>[</span>18<span>]</span></sup></font></p>
<h2><span class="editsection"></span><span class="mw-headline">See also</span></h2>
+
<p><font color="#000000"></font></p>
 +
<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000">See also about <span class="mw-headline"><font color="#000000">C. elegans </font></span></font></span></h2>
 
<ul>
 
<ul>
     <li><a href="/wiki/Animal_testing_on_invertebrates" title="Animal testing on invertebrates">Animal testing on invertebrates</a> </li>
+
     <li><font color="#000000">Animal testing on invertebrates </font></li>
 
</ul>
 
</ul>
<p><a name="References" id="References"></a></p>
+
<p><font color="#000000"></font></p>
<h2><span class="editsection"></span><span class="mw-headline">References</span></h2>
+
<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>References</font></span></h2>
 
<div class="references-small">
 
<div class="references-small">
 
<ol class="references">
 
<ol class="references">
     <li id="cite_note-0"><strong><a href="#cite_ref-0" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFBrenner.2C_S.1974" class="Journal">Brenner, S. (May 1974). &quot;<a rel="nofollow" href="http://dev.wormbase.org/papers/31_Brenner74.pdf" title="http://dev.wormbase.org/papers/31_Brenner74.pdf" class="external text">The Genetics  of <em>Caenorhabditis elegans</em></a>&quot; (PDF). <em><a href="/wiki/Genetics_(journal)" title="Genetics (journal)">Genetics</a></em> <strong>77</strong>: 71&ndash;94<span class="printonly">. <a rel="nofollow" href="http://dev.wormbase.org/papers/31_Brenner74.pdf" title="http://dev.wormbase.org/papers/31_Brenner74.pdf" class="external free">http://dev.wormbase.org/papers/31_Brenner74.pdf</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=The+Genetics+of+%27%27Caenorhabditis+elegans%27%27&amp;rft.jtitle=%5B%5BGenetics+%28journal%29%7CGenetics%5D%5D&amp;rft.aulast=Brenner%2C+S.&amp;rft.au=Brenner%2C+S.&amp;rft.date=May+1974&amp;rft.volume=77&amp;rft.pages=71%E2%80%9394&amp;rft_id=http%3A%2F%2Fdev.wormbase.org%2Fpapers%2F31_Brenner74.pdf&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
     <li id="cite_note-0"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFBrenner.2C_S.1974" style="FONT-STYLE: normal">Brenner, S. (May 1974). &quot;The Genetics of <em>Caenorhabditis elegans</em>&quot; (PDF). <em>Genetics</em> <strong>77</strong>: 71&ndash;94<span class="printonly">. http://dev.wormbase.org/papers/31_Brenner74.pdf</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=The+Genetics+of+%27%27Caenorhabditis+elegans%27%27&amp;rft.jtitle=%5B%5BGenetics+%28journal%29%7CGenetics%5D%5D&amp;rft.aulast=Brenner%2C+S.&amp;rft.au=Brenner%2C+S.&amp;rft.date=May+1974&amp;rft.volume=77&amp;rft.pages=71%E2%80%9394&amp;rft_id=http%3A%2F%2Fdev.wormbase.org%2Fpapers%2F31_Brenner74.pdf&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-1"><strong><a href="#cite_ref-1" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFNayak.2C_S..2C_J._Goree_.26_T._Schedl2004" class="Journal">Nayak, S., J. Goree &amp; T. Schedl (2004). &quot;<a rel="nofollow" href="http://biology.plosjournals.org/perlserv/?request=get-document&amp;doi=10.1371/journal.pbio.0030006" title="http://biology.plosjournals.org/perlserv/?request=get-document&amp;doi=10.1371/journal.pbio.0030006" class="external text"><em>fog-2</em> and the Evolution of Self-Fertile Hermaphroditism in  <em>Caenorhabditis</em></a>&quot;. <em><a href="/wiki/PLoS_Biology" title="PLoS Biology">PLoS Biology</a></em> <strong>3</strong> (1): e6. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1371%2Fjournal.pbio.0030006" title="http://dx.doi.org/10.1371%2Fjournal.pbio.0030006" class="external text">10.1371/journal.pbio.0030006</a></span><span class="printonly">. <a rel="nofollow" href="http://biology.plosjournals.org/perlserv/?request=get-document&amp;doi=10.1371/journal.pbio.0030006" title="http://biology.plosjournals.org/perlserv/?request=get-document&amp;doi=10.1371/journal.pbio.0030006" class="external free">http://biology.plosjournals.org/perlserv/?request=get-document&amp;doi=10.1371/journal.pbio.0030006</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=%27%27fog-2%27%27+and+the+Evolution+of+Self-Fertile+Hermaphroditism+in+%27%27Caenorhabditis%27%27&amp;rft.jtitle=%5B%5BPLoS+Biology%5D%5D&amp;rft.aulast=Nayak%2C+S.%2C+J.+Goree+%26+T.+Schedl&amp;rft.au=Nayak%2C+S.%2C+J.+Goree+%26+T.+Schedl&amp;rft.date=2004&amp;rft.volume=3&amp;rft.issue=1&amp;rft.pages=e6&amp;rft_id=info:doi/10.1371%2Fjournal.pbio.0030006&amp;rft_id=http%3A%2F%2Fbiology.plosjournals.org%2Fperlserv%2F%3Frequest%3Dget-document%26doi%3D10.1371%2Fjournal.pbio.0030006&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
    <li id="cite_note-1"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFNayak.2C_S..2C_J._Goree_.26_T._Schedl2004" style="FONT-STYLE: normal">Nayak, S., J. Goree &amp; T. Schedl (2004). &quot;<em>fog-2</em> and the Evolution of Self-Fertile Hermaphroditism in <em>Caenorhabditis</em>&quot;. <em>PLoS Biology</em> <strong>3</strong> (1): e6. doi:<span class="neverexpand">10.1371/journal.pbio.0030006</span><span class="printonly">. http://biology.plosjournals.org/perlserv/?request=get-document&amp;doi=10.1371/journal.pbio.0030006</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=%27%27fog-2%27%27+and+the+Evolution+of+Self-Fertile+Hermaphroditism+in+%27%27Caenorhabditis%27%27&amp;rft.jtitle=%5B%5BPLoS+Biology%5D%5D&amp;rft.aulast=Nayak%2C+S.%2C+J.+Goree+%26+T.+Schedl&amp;rft.au=Nayak%2C+S.%2C+J.+Goree+%26+T.+Schedl&amp;rft.date=2004&amp;rft.volume=3&amp;rft.issue=1&amp;rft.pages=e6&amp;rft_id=info:doi/10.1371%2Fjournal.pbio.0030006&amp;rft_id=http%3A%2F%2Fbiology.plosjournals.org%2Fperlserv%2F%3Frequest%3Dget-document%26doi%3D10.1371%2Fjournal.pbio.0030006&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
     <li id="cite_note-2"><strong><a href="#cite_ref-2" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFShaham_S.2006" class="Journal">Shaham S. (March 14 2006). &quot;<a rel="nofollow" href="http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&amp;blobtype=pdf" title="http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&amp;blobtype=pdf" class="external text">Worming into the cell: Viral reproduction in Caenorhabditis  elegans</a>&quot; (PDF). <em>Proc Natl Acad Sci USA</em> <strong>103</strong> (11): 3955&ndash;56. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1073%2Fpnas.0600779103" title="http://dx.doi.org/10.1073%2Fpnas.0600779103" class="external text">10.1073/pnas.0600779103</a></span>. <a href="http://www.ncbi.nlm.nih.gov/pubmed/16537467" title="http://www.ncbi.nlm.nih.gov/pubmed/16537467" class="external">PMID 16537467</a><span class="printonly">. <a rel="nofollow" href="http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&amp;blobtype=pdf" title="http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&amp;blobtype=pdf" class="external free">http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&amp;blobtype=pdf</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Worming+into+the+cell%3A+Viral+reproduction+in+Caenorhabditis+elegans&amp;rft.jtitle=Proc+Natl+Acad+Sci+USA&amp;rft.aulast=Shaham+S.&amp;rft.au=Shaham+S.&amp;rft.date=March+14+2006&amp;rft.volume=103&amp;rft.issue=11&amp;rft.pages=3955%E2%80%9356&amp;rft_id=info:doi/10.1073%2Fpnas.0600779103&amp;rft_id=info:pmid/16537467&amp;rft_id=http%3A%2F%2Fwww.pubmedcentral.nih.gov%2Fpicrender.fcgi%3Fartid%3D1449626%26blobtype%3Dpdf&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span>  </li>
+
    <li id="cite_note-2"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFShaham_S.2006" style="FONT-STYLE: normal">Shaham S. (March 14 2006). &quot;Worming into the cell: Viral reproduction in Caenorhabditis elegans&quot; (PDF). <em>Proc Natl Acad Sci USA</em> <strong>103</strong> (11): 3955&ndash;56. doi:<span class="neverexpand">10.1073/pnas.0600779103</span>. PMID 16537467<span class="printonly">. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&amp;blobtype=pdf</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Worming+into+the+cell%3A+Viral+reproduction+in+Caenorhabditis+elegans&amp;rft.jtitle=Proc+Natl+Acad+Sci+USA&amp;rft.aulast=Shaham+S.&amp;rft.au=Shaham+S.&amp;rft.date=March+14+2006&amp;rft.volume=103&amp;rft.issue=11&amp;rft.pages=3955%E2%80%9356&amp;rft_id=info:doi/10.1073%2Fpnas.0600779103&amp;rft_id=info:pmid/16537467&amp;rft_id=http%3A%2F%2Fwww.pubmedcentral.nih.gov%2Fpicrender.fcgi%3Fartid%3D1449626%26blobtype%3Dpdf&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-3"><strong><a href="#cite_ref-3" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFWatts_D._J._.26_S._H._Strogatz1998" class="Journal">Watts D. J. &amp; S. H. Strogatz (June 1998). &quot;<a rel="nofollow" href="http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html" title="http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html" class="external text">Collective dynamics of 'small-world' networks</a>&quot;. <em><a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a></em> <strong>393</strong> (6684): 440&ndash;442. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1038%2F30918" title="http://dx.doi.org/10.1038%2F30918" class="external text">10.1038/30918</a></span><span class="printonly">. <a rel="nofollow" href="http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html" title="http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html" class="external free">http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Collective+dynamics+of+%27small-world%27+networks&amp;rft.jtitle=%5B%5BNature+%28journal%29%7CNature%5D%5D&amp;rft.aulast=Watts+D.+J.+%26+S.+H.+Strogatz&amp;rft.au=Watts+D.+J.+%26+S.+H.+Strogatz&amp;rft.date=June+1998&amp;rft.volume=393&amp;rft.issue=6684&amp;rft.pages=440%E2%80%93442&amp;rft_id=info:doi/10.1038%2F30918&amp;rft_id=http%3A%2F%2Fwww.nature.com%2Fnature%2Fjournal%2Fv393%2Fn6684%2Fabs%2F393440a0.html&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
     <li id="cite_note-3"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFWatts_D._J._.26_S._H._Strogatz1998" style="FONT-STYLE: normal">Watts D. J. &amp; S. H. Strogatz (June 1998). &quot;Collective dynamics of 'small-world' networks&quot;. <em>Nature</em> <strong>393</strong> (6684): 440&ndash;442. doi:<span class="neverexpand">10.1038/30918</span><span class="printonly">. http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Collective+dynamics+of+%27small-world%27+networks&amp;rft.jtitle=%5B%5BNature+%28journal%29%7CNature%5D%5D&amp;rft.aulast=Watts+D.+J.+%26+S.+H.+Strogatz&amp;rft.au=Watts+D.+J.+%26+S.+H.+Strogatz&amp;rft.date=June+1998&amp;rft.volume=393&amp;rft.issue=6684&amp;rft.pages=440%E2%80%93442&amp;rft_id=info:doi/10.1038%2F30918&amp;rft_id=http%3A%2F%2Fwww.nature.com%2Fnature%2Fjournal%2Fv393%2Fn6684%2Fabs%2F393440a0.html&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-4"><strong><a href="#cite_ref-4" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFFeng_et_al.2006" class="Journal">Feng et al. (November 2006). &quot;<a rel="nofollow" href="http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955" title="http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955" class="external text">A C. elegans Model of Nicotine-Dependent Behavior: Regulation by  TRP-Family Channels</a>&quot;. <em><a href="/wiki/Cell_(journal)" title="Cell (journal)">Cell</a></em> <strong>127</strong>: 621&ndash;633. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1016%2Fj.cell.2006.09.035" title="http://dx.doi.org/10.1016%2Fj.cell.2006.09.035" class="external text">10.1016/j.cell.2006.09.035</a></span>. <a href="http://www.ncbi.nlm.nih.gov/pubmed/17081982" title="http://www.ncbi.nlm.nih.gov/pubmed/17081982" class="external">PMID 17081982</a><span class="printonly">. <a rel="nofollow" href="http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955" title="http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955" class="external free">http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=A+C.+elegans+Model+of+Nicotine-Dependent+Behavior%3A+Regulation+by+TRP-Family+Channels&amp;rft.jtitle=%5B%5BCell+%28journal%29%7CCell%5D%5D&amp;rft.aulast=Feng+et+al.&amp;rft.au=Feng+et+al.&amp;rft.date=November+2006&amp;rft.volume=127&amp;rft.pages=621%E2%80%93633&amp;rft_id=info:doi/10.1016%2Fj.cell.2006.09.035&amp;rft_id=info:pmid/17081982&amp;rft_id=http%3A%2F%2Fwww.cell.com%2Fcontent%2Farticle%2Fabstract%3Fuid%3DPIIS0092867406012955&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
    <li id="cite_note-4"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFFeng_et_al.2006" style="FONT-STYLE: normal">Feng et al. (November 2006). &quot;A C. elegans Model of Nicotine-Dependent Behavior: Regulation by TRP-Family Channels&quot;. <em>Cell</em> <strong>127</strong>: 621&ndash;633. doi:<span class="neverexpand">10.1016/j.cell.2006.09.035</span>. PMID 17081982<span class="printonly">. http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=A+C.+elegans+Model+of+Nicotine-Dependent+Behavior%3A+Regulation+by+TRP-Family+Channels&amp;rft.jtitle=%5B%5BCell+%28journal%29%7CCell%5D%5D&amp;rft.aulast=Feng+et+al.&amp;rft.au=Feng+et+al.&amp;rft.date=November+2006&amp;rft.volume=127&amp;rft.pages=621%E2%80%93633&amp;rft_id=info:doi/10.1016%2Fj.cell.2006.09.035&amp;rft_id=info:pmid/17081982&amp;rft_id=http%3A%2F%2Fwww.cell.com%2Fcontent%2Farticle%2Fabstract%3Fuid%3DPIIS0092867406012955&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
     <li id="cite_note-5"><strong><a href="#cite_ref-5" title="">^</a></strong> &quot;<a rel="nofollow" href="http://wormbase.org/external/2007/nematode_isolation_guide/nematode_isolation_guide.html" title="http://wormbase.org/external/2007/nematode_isolation_guide/nematode_isolation_guide.html" class="external text"><em>Caenorhabditis</em> isolation guide</a>&quot;. WormBase. Retrieved on 2007-08-30. </li>
+
    <li id="cite_note-5"><font color="#000000"><strong>^</strong> &quot;<em>Caenorhabditis</em> isolation guide&quot;. WormBase. Retrieved on 2007-08-30. </font></li>
     <li id="cite_note-6"><strong><a href="#cite_ref-6" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFDolgin2007" class="Journal">Dolgin, Elie  (August 2007). &quot;Slime for a dime&quot;. <em><a href="/wiki/Science_(journal)" title="Science (journal)">Science</a></em> <strong>317</strong> (5842): 1157. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1126%2Fscience.317.5842.1157b" title="http://dx.doi.org/10.1126%2Fscience.317.5842.1157b" class="external text">10.1126/science.317.5842.1157b</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Slime+for+a+dime&amp;rft.jtitle=%5B%5BScience+%28journal%29%7CScience%5D%5D&amp;rft.aulast=Dolgin&amp;rft.aufirst=Elie&amp;rft.au=Dolgin%2C+Elie&amp;rft.date=August+2007&amp;rft.volume=317&amp;rft.issue=5842&amp;rft.pages=1157&amp;rft_id=info:doi/10.1126%2Fscience.317.5842.1157b&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
    <li id="cite_note-6"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFDolgin2007" style="FONT-STYLE: normal">Dolgin, Elie (August 2007). &quot;Slime for a dime&quot;. <em>Science</em> <strong>317</strong> (5842): 1157. doi:<span class="neverexpand">10.1126/science.317.5842.1157b</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Slime+for+a+dime&amp;rft.jtitle=%5B%5BScience+%28journal%29%7CScience%5D%5D&amp;rft.aulast=Dolgin&amp;rft.aufirst=Elie&amp;rft.au=Dolgin%2C+Elie&amp;rft.date=August+2007&amp;rft.volume=317&amp;rft.issue=5842&amp;rft.pages=1157&amp;rft_id=info:doi/10.1126%2Fscience.317.5842.1157b&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
     <li id="cite_note-7"><strong><a href="#cite_ref-7" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFThe_.27.27C._elegans.27.27_Sequencing_Consortium1998" class="Journal">The <em>C. elegans</em> Sequencing Consortium (1998). &quot;<a rel="nofollow" href="http://www.sciencemag.org/cgi/content/abstract/282/5396/2012" title="http://www.sciencemag.org/cgi/content/abstract/282/5396/2012" class="external text">Genome sequence of the nematode <em>C. elegans</em>: a platform for  investigating biology</a>&quot;. <em><a href="/wiki/Science_(journal)" title="Science (journal)">Science</a></em> <strong>282</strong>: 2012&ndash;2018. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1126%2Fscience.282.5396.2012" title="http://dx.doi.org/10.1126%2Fscience.282.5396.2012" class="external text">10.1126/science.282.5396.2012</a></span>. <a href="http://www.ncbi.nlm.nih.gov/pubmed/9851916" title="http://www.ncbi.nlm.nih.gov/pubmed/9851916" class="external">PMID 9851916</a><span class="printonly">. <a rel="nofollow" href="http://www.sciencemag.org/cgi/content/abstract/282/5396/2012" title="http://www.sciencemag.org/cgi/content/abstract/282/5396/2012" class="external free">http://www.sciencemag.org/cgi/content/abstract/282/5396/2012</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Genome+sequence+of+the+nematode+%27%27C.+elegans%27%27%3A+a+platform+for+investigating+biology&amp;rft.jtitle=%5B%5BScience+%28journal%29%7CScience%5D%5D&amp;rft.aulast=The+%27%27C.+elegans%27%27+Sequencing+Consortium&amp;rft.au=The+%27%27C.+elegans%27%27+Sequencing+Consortium&amp;rft.date=1998&amp;rft.volume=282&amp;rft.pages=2012%E2%80%932018&amp;rft_id=info:doi/10.1126%2Fscience.282.5396.2012&amp;rft_id=info:pmid/9851916&amp;rft_id=http%3A%2F%2Fwww.sciencemag.org%2Fcgi%2Fcontent%2Fabstract%2F282%2F5396%2F2012&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span>  </li>
+
    <li id="cite_note-7"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFThe_.27.27C._elegans.27.27_Sequencing_Consortium1998" style="FONT-STYLE: normal">The <em>C. elegans</em> Sequencing Consortium (1998). &quot;Genome sequence of the nematode <em>C. elegans</em>: a platform for investigating biology&quot;. <em>Science</em> <strong>282</strong>: 2012&ndash;2018. doi:<span class="neverexpand">10.1126/science.282.5396.2012</span>. PMID 9851916<span class="printonly">. http://www.sciencemag.org/cgi/content/abstract/282/5396/2012</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Genome+sequence+of+the+nematode+%27%27C.+elegans%27%27%3A+a+platform+for+investigating+biology&amp;rft.jtitle=%5B%5BScience+%28journal%29%7CScience%5D%5D&amp;rft.aulast=The+%27%27C.+elegans%27%27+Sequencing+Consortium&amp;rft.au=The+%27%27C.+elegans%27%27+Sequencing+Consortium&amp;rft.date=1998&amp;rft.volume=282&amp;rft.pages=2012%E2%80%932018&amp;rft_id=info:doi/10.1126%2Fscience.282.5396.2012&amp;rft_id=info:pmid/9851916&amp;rft_id=http%3A%2F%2Fwww.sciencemag.org%2Fcgi%2Fcontent%2Fabstract%2F282%2F5396%2F2012&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-8"><strong><a href="#cite_ref-8" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFStein.2C_L._D._.27.27et_al..27.272003" class="Journal">Stein, L. D. <em>et al.</em> (2003). &quot;The Genome  Sequence of <em>Caenorhabditis briggsae</em>: A Platform for Comparative  Genomics&quot;. <em><a href="/wiki/PLoS_Biology" title="PLoS Biology">PLoS  Biology</a></em> <strong>1</strong>: 166&ndash;192. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1371%2Fjournal.pbio.0000045" title="http://dx.doi.org/10.1371%2Fjournal.pbio.0000045" class="external text">10.1371/journal.pbio.0000045</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=The+Genome+Sequence+of+%27%27Caenorhabditis+briggsae%27%27%3A+A+Platform+for+Comparative+Genomics&amp;rft.jtitle=%5B%5BPLoS+Biology%5D%5D&amp;rft.aulast=Stein%2C+L.+D.+%27%27et+al.%27%27&amp;rft.au=Stein%2C+L.+D.+%27%27et+al.%27%27&amp;rft.date=2003&amp;rft.volume=1&amp;rft.pages=166%E2%80%93192&amp;rft_id=info:doi/10.1371%2Fjournal.pbio.0000045&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span>  </li>
+
    <li id="cite_note-8"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFStein.2C_L._D._.27.27et_al..27.272003" style="FONT-STYLE: normal">Stein, L. D. <em>et al.</em> (2003). &quot;The Genome Sequence of <em>Caenorhabditis briggsae</em>: A Platform for Comparative Genomics&quot;. <em>PLoS Biology</em> <strong>1</strong>: 166&ndash;192. doi:<span class="neverexpand">10.1371/journal.pbio.0000045</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=The+Genome+Sequence+of+%27%27Caenorhabditis+briggsae%27%27%3A+A+Platform+for+Comparative+Genomics&amp;rft.jtitle=%5B%5BPLoS+Biology%5D%5D&amp;rft.aulast=Stein%2C+L.+D.+%27%27et+al.%27%27&amp;rft.au=Stein%2C+L.+D.+%27%27et+al.%27%27&amp;rft.date=2003&amp;rft.volume=1&amp;rft.pages=166%E2%80%93192&amp;rft_id=info:doi/10.1371%2Fjournal.pbio.0000045&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-9"><strong><a href="#cite_ref-9" title="">^</a></strong> Genome Sequencing  Center. &quot;<a rel="nofollow" href="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20remanei" title="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20remanei" class="external text"><em>Caenorhabditis remanei</em>: Background</a>&quot;. <a href="/wiki/Washington_University_School_of_Medicine" title="Washington University School of Medicine">Washington University  School of Medicine</a>. Retrieved on 2008-07-11.  </li>
+
     <li id="cite_note-9"><font color="#000000"><strong>^</strong> Genome Sequencing Center. &quot;<em>Caenorhabditis remanei</em>: Background&quot;. Washington University School of Medicine. Retrieved on 2008-07-11. </font></li>
    <li id="cite_note-10"><strong><a href="#cite_ref-10" title="">^</a></strong> Genome  Sequencing Center. &quot;<a rel="nofollow" href="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20japonica" title="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20japonica" class="external text"><em>Caenorhabditis japonica</em>: Background</a>&quot;. <a href="/wiki/Washington_University_School_of_Medicine" title="Washington University School of Medicine">Washington University  School of Medicine</a>. Retrieved on 2008-07-11.  </li>
+
    <li id="cite_note-10"><font color="#000000"><strong>^</strong> Genome Sequencing Center. &quot;<em>Caenorhabditis japonica</em>: Background&quot;. Washington University School of Medicine. Retrieved on 2008-07-11. </font></li>
    <li id="cite_note-11"><strong><a href="#cite_ref-11" title="">^</a></strong> Genome  Sequencing Center. &quot;<a rel="nofollow" href="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20brenneri" title="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20brenneri" class="external text"><em>Caenorhabditis brenneri</em>: Background</a>&quot;. <a href="/wiki/Washington_University_School_of_Medicine" title="Washington University School of Medicine">Washington University  School of Medicine</a>. Retrieved on 2008-07-11.  </li>
+
     <li id="cite_note-11"><font color="#000000"><strong>^</strong> Genome Sequencing Center. &quot;<em>Caenorhabditis brenneri</em>: Background&quot;. Washington University School of Medicine. Retrieved on 2008-07-11. </font></li>
    <li id="cite_note-WS169-12"><strong><a href="#cite_ref-WS169_12-0" title="">^</a></strong>  &quot;<a rel="nofollow" href="http://www.wormbase.org/wiki/index.php/WS169" title="http://www.wormbase.org/wiki/index.php/WS169" class="external text">WormBaseWiki  WS169 release notes</a>&quot;. <a href="/wiki/Wormbase" title="Wormbase">Wormbase</a>.  Retrieved on 2007-02-21.  </li>
+
    <li id="cite_note-WS169-12"><font color="#000000"><strong>^</strong> &quot;WormBaseWiki WS169 release notes&quot;. Wormbase. Retrieved on 2007-02-21. </font></li>
    <li id="cite_note-WS159-13"><strong><a href="#cite_ref-WS159_13-0" title="">^</a></strong>  &quot;<a rel="nofollow" href="http://www.wormbase.org/wiki/index.php/WS159" title="http://www.wormbase.org/wiki/index.php/WS159" class="external text">WormBaseWiki  WS159 release notes</a>&quot;. <a href="/wiki/Wormbase" title="Wormbase">Wormbase</a>.  Retrieved on 2007-01-21.  </li>
+
    <li id="cite_note-WS159-13"><font color="#000000"><strong>^</strong> &quot;WormBaseWiki WS159 release notes&quot;. Wormbase. Retrieved on 2007-01-21. </font></li>
    <li id="cite_note-14"><strong><a href="#cite_ref-14" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFGamulin2000" class="Journal">Gamulin, V  (December 2000). &quot;Sponge proteins are more similar to those of <em>Homo  sapiens</em> than to <em>Caenorhabditis elegans</em>&quot;. <em>Biological Journal of the  Linnean Society</em> (Academic Press) <strong>71</strong> (4): 821&ndash;828.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Sponge+proteins+are+more+similar+to+those+of+%27%27Homo+sapiens%27%27+than+to+%27%27Caenorhabditis+elegans%27%27&amp;rft.jtitle=Biological+Journal+of+the+Linnean+Society&amp;rft.aulast=Gamulin&amp;rft.aufirst=V&amp;rft.au=Gamulin%2C+V&amp;rft.date=December+2000&amp;rft.volume=71&amp;rft.issue=4&amp;rft.pages=821%E2%80%93828&amp;rft.pub=Academic+Press&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span>  </li>
+
    <li id="cite_note-14"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFGamulin2000" style="FONT-STYLE: normal">Gamulin, V (December 2000). &quot;Sponge proteins are more similar to those of <em>Homo sapiens</em> than to <em>Caenorhabditis elegans</em>&quot;. <em>Biological Journal of the Linnean Society</em> (Academic Press) <strong>71</strong> (4): 821&ndash;828.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Sponge+proteins+are+more+similar+to+those+of+%27%27Homo+sapiens%27%27+than+to+%27%27Caenorhabditis+elegans%27%27&amp;rft.jtitle=Biological+Journal+of+the+Linnean+Society&amp;rft.aulast=Gamulin&amp;rft.aufirst=V&amp;rft.au=Gamulin%2C+V&amp;rft.date=December+2000&amp;rft.volume=71&amp;rft.issue=4&amp;rft.pages=821%E2%80%93828&amp;rft.pub=Academic+Press&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-15"><strong><a href="#cite_ref-15" title="">^</a></strong> <cite style="font-style: normal;" id="CITEREFFire_A.2C_Xu_S.2C_Montgomery_MK.2C_Kostas_SA.2C_Driver_SE.2C_Mello_CC1998" class="Journal">Fire A, Xu S, Montgomery MK, Kostas SA, Driver SE,  Mello CC (February 1998). &quot;Potent and specific genetic interference by  double-stranded RNA in Caenorhabditis elegans&quot;. <em>Nature</em> <strong>391</strong> (6669):  806&ndash;11. <a href="/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<span class="neverexpand"><a rel="nofollow" href="http://dx.doi.org/10.1038%2F35888" title="http://dx.doi.org/10.1038%2F35888" class="external text">10.1038/35888</a></span>.  <a href="http://www.ncbi.nlm.nih.gov/pubmed/9486653" title="http://www.ncbi.nlm.nih.gov/pubmed/9486653" class="external">PMID 9486653</a>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Potent+and+specific+genetic+interference+by+double-stranded+RNA+in+Caenorhabditis+elegans&amp;rft.jtitle=Nature&amp;rft.aulast=Fire+A%2C+Xu+S%2C+Montgomery+MK%2C+Kostas+SA%2C+Driver+SE%2C+Mello+CC&amp;rft.au=Fire+A%2C+Xu+S%2C+Montgomery+MK%2C+Kostas+SA%2C+Driver+SE%2C+Mello+CC&amp;rft.date=February+1998&amp;rft.volume=391&amp;rft.issue=6669&amp;rft.pages=806%E2%80%9311&amp;rft_id=info:doi/10.1038%2F35888&amp;rft_id=info:pmid/9486653&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span>  </li>
+
     <li id="cite_note-15"><font color="#000000"><strong>^</strong> <cite class="Journal" id="CITEREFFire_A.2C_Xu_S.2C_Montgomery_MK.2C_Kostas_SA.2C_Driver_SE.2C_Mello_CC1998" style="FONT-STYLE: normal">Fire A, Xu S, Montgomery MK, Kostas SA, Driver SE, Mello CC (February 1998). &quot;Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans&quot;. <em>Nature</em> <strong>391</strong> (6669): 806&ndash;11. doi:<span class="neverexpand">10.1038/35888</span>. PMID 9486653.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.atitle=Potent+and+specific+genetic+interference+by+double-stranded+RNA+in+Caenorhabditis+elegans&amp;rft.jtitle=Nature&amp;rft.aulast=Fire+A%2C+Xu+S%2C+Montgomery+MK%2C+Kostas+SA%2C+Driver+SE%2C+Mello+CC&amp;rft.au=Fire+A%2C+Xu+S%2C+Montgomery+MK%2C+Kostas+SA%2C+Driver+SE%2C+Mello+CC&amp;rft.date=February+1998&amp;rft.volume=391&amp;rft.issue=6669&amp;rft.pages=806%E2%80%9311&amp;rft_id=info:doi/10.1038%2F35888&amp;rft_id=info:pmid/9486653&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-16"><strong><a href="#cite_ref-16" title="">^</a></strong> &quot;<a rel="nofollow" href="http://news.bbc.co.uk/1/hi/sci/tech/2992123.stm" title="http://news.bbc.co.uk/1/hi/sci/tech/2992123.stm" class="external text">Worms  survived Columbia disaster</a>&quot;, <a href="/wiki/BBC_News" title="BBC News">BBC  News</a> (2003-05-01)<span class="reference-accessdate">. Retrieved on 11 July  2008</span>.<span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&amp;rft.type=newspaperArticle&amp;rft.subject=News&amp;rft.title=Worms+survived+Columbia+disaster&amp;rft.identifier=http%3A%2F%2Fnews.bbc.co.uk%2F1%2Fhi%2Fsci%2Ftech%2F2992123.stm&amp;rft.publisher=%5B%5BBBC+News%5D%5D&amp;rft.date=2003-05-01" class="Z3988"><span style="display: none;">&nbsp;</span></span>  </li>
+
    <li id="cite_note-16"><font color="#000000"><strong>^</strong> &quot;Worms survived Columbia disaster&quot;, BBC News (2003-05-01)<span class="reference-accessdate">. Retrieved on 11 July 2008</span>.<span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&amp;rft.type=newspaperArticle&amp;rft.subject=News&amp;rft.title=Worms+survived+Columbia+disaster&amp;rft.identifier=http%3A%2F%2Fnews.bbc.co.uk%2F1%2Fhi%2Fsci%2Ftech%2F2992123.stm&amp;rft.publisher=%5B%5BBBC+News%5D%5D&amp;rft.date=2003-05-01"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
    <li id="cite_note-17"><strong><a href="#cite_ref-17" title="">^</a></strong> <a rel="nofollow" href="http://news.bbc.co.uk/1/hi/england/nottinghamshire/7835020.stm" title="http://news.bbc.co.uk/1/hi/england/nottinghamshire/7835020.stm" class="external free">http://news.bbc.co.uk/1/hi/england/nottinghamshire/7835020.stm</a> </li>
+
    <li id="cite_note-17"><font color="#000000"><strong>^</strong> http://news.bbc.co.uk/1/hi/england/nottinghamshire/7835020.stm </font></li>
 
</ol>
 
</ol>
 
</div>
 
</div>
<p><a name="Publications" id="Publications"></a></p>
+
<p><font color="#000000"></font></p>
<h2><span class="editsection"></span><span class="mw-headline">Publications</span></h2>
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<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Publications</font></span></h2>
 
<ul>
 
<ul>
     <li><cite style="font-style: normal;" id="CITEREFBird.2C_Jean.3B_Bird.2C_Alan_C.1991" class="book">Bird, Jean; Bird, Alan C. (1991). <em>The structure of nematodes</em>. Boston: <a href="/wiki/Academic_Press" title="Academic Press">Academic Press</a>. pp.&nbsp;1, 69&ndash;70, 152&ndash;153, 165, 224&ndash;225. <a href="/wiki/Special:BookSources/0120996510" class="internal">ISBN 0-12-099651-0</a>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=The+structure+of+nematodes&amp;rft.aulast=Bird%2C+Jean%3B+Bird%2C+Alan+C.&amp;rft.au=Bird%2C+Jean%3B+Bird%2C+Alan+C.&amp;rft.date=1991&amp;rft.pages=pp.%26nbsp%3B1%2C+69%E2%80%9370%2C+152%E2%80%93153%2C+165%2C+224%E2%80%93225&amp;rft.place=Boston&amp;rft.pub=%5B%5BAcademic+Press%5D%5D&amp;rft.isbn=0-12-099651-0&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
     <li><font color="#000000"><cite class="book" id="CITEREFBird.2C_Jean.3B_Bird.2C_Alan_C.1991" style="FONT-STYLE: normal">Bird, Jean; Bird, Alan C. (1991). <em>The structure of nematodes</em>. Boston: Academic Press. pp.&nbsp;1, 69&ndash;70, 152&ndash;153, 165, 224&ndash;225. ISBN 0-12-099651-0.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=The+structure+of+nematodes&amp;rft.aulast=Bird%2C+Jean%3B+Bird%2C+Alan+C.&amp;rft.au=Bird%2C+Jean%3B+Bird%2C+Alan+C.&amp;rft.date=1991&amp;rft.pages=pp.%26nbsp%3B1%2C+69%E2%80%9370%2C+152%E2%80%93153%2C+165%2C+224%E2%80%93225&amp;rft.place=Boston&amp;rft.pub=%5B%5BAcademic+Press%5D%5D&amp;rft.isbn=0-12-099651-0&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
 
</ul>
 
</ul>
 
<ul>
 
<ul>
     <li><cite style="font-style: normal;" id="CITEREFHope.2C_Ian_A.1999" class="book">Hope, Ian A. (1999). <em>C. elegans: a practical approach</em>. Oxford [Oxfordshire]: <a href="/wiki/Oxford_University_Press" title="Oxford University Press">Oxford University Press</a>. pp.&nbsp;1&ndash;6. <a href="/wiki/Special:BookSources/0199637385" class="internal">ISBN 0-19-963738-5</a>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=C.+elegans%3A+a+practical+approach&amp;rft.aulast=Hope%2C+Ian+A.&amp;rft.au=Hope%2C+Ian+A.&amp;rft.date=1999&amp;rft.pages=pp.%26nbsp%3B1%E2%80%936&amp;rft.place=Oxford+%5BOxfordshire%5D&amp;rft.pub=%5B%5BOxford+University+Press%5D%5D&amp;rft.isbn=0-19-963738-5&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
     <li><font color="#000000"><cite class="book" id="CITEREFHope.2C_Ian_A.1999" style="FONT-STYLE: normal">Hope, Ian A. (1999). <em>C. elegans: a practical approach</em>. Oxford [Oxfordshire]: Oxford University Press. pp.&nbsp;1&ndash;6. ISBN 0-19-963738-5.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=C.+elegans%3A+a+practical+approach&amp;rft.aulast=Hope%2C+Ian+A.&amp;rft.au=Hope%2C+Ian+A.&amp;rft.date=1999&amp;rft.pages=pp.%26nbsp%3B1%E2%80%936&amp;rft.place=Oxford+%5BOxfordshire%5D&amp;rft.pub=%5B%5BOxford+University+Press%5D%5D&amp;rft.isbn=0-19-963738-5&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
 
</ul>
 
</ul>
 
<ul>
 
<ul>
     <li><cite style="font-style: normal;" id="CITEREFRiddle.2C_D.L..2C_T._Blumenthal.2C_R._J._Meyer_.26_J._R._Priess1997" class="book">Riddle, D.L., T. Blumenthal, R. J. Meyer &amp; J. R. Priess (1997). <em><a rel="nofollow" href="http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=ce2" title="http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=ce2" class="external text">C. elegans <em>II</em></a></em>. Cold Spring Harbor Laboratory Press, New York. pp.&nbsp;1&ndash;4, 679&ndash;683. <a href="/wiki/Special:BookSources/0879695323" class="internal">ISBN 0-87969-532-3</a><span class="printonly">. <a rel="nofollow" href="http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=ce2" title="http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=ce2" class="external free">http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=ce2</a></span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=%27%27C.+elegans%27%27+II&amp;rft.aulast=Riddle%2C+D.L.%2C+T.+Blumenthal%2C+R.+J.+Meyer+%26+J.+R.+Priess&amp;rft.au=Riddle%2C+D.L.%2C+T.+Blumenthal%2C+R.+J.+Meyer+%26+J.+R.+Priess&amp;rft.date=1997&amp;rft.pages=pp.%26nbsp%3B1%E2%80%934%2C+679%E2%80%93683&amp;rft.pub=Cold+Spring+Harbor+Laboratory+Press%2C+New+York&amp;rft.isbn=0-87969-532-3&amp;rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fbooks%2Fbv.fcgi%3Frid%3Dce2&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans" class="Z3988"><span style="display: none;">&nbsp;</span></span> </li>
+
     <li><font color="#000000"><cite class="book" id="CITEREFRiddle.2C_D.L..2C_T._Blumenthal.2C_R._J._Meyer_.26_J._R._Priess1997" style="FONT-STYLE: normal">Riddle, D.L., T. Blumenthal, R. J. Meyer &amp; J. R. Priess (1997). <em>C. elegans <em>II</em></em>. Cold Spring Harbor Laboratory Press, New York. pp.&nbsp;1&ndash;4, 679&ndash;683. ISBN 0-87969-532-3<span class="printonly">. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=ce2</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=%27%27C.+elegans%27%27+II&amp;rft.aulast=Riddle%2C+D.L.%2C+T.+Blumenthal%2C+R.+J.+Meyer+%26+J.+R.+Priess&amp;rft.au=Riddle%2C+D.L.%2C+T.+Blumenthal%2C+R.+J.+Meyer+%26+J.+R.+Priess&amp;rft.date=1997&amp;rft.pages=pp.%26nbsp%3B1%E2%80%934%2C+679%E2%80%93683&amp;rft.pub=Cold+Spring+Harbor+Laboratory+Press%2C+New+York&amp;rft.isbn=0-87969-532-3&amp;rft_id=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fbooks%2Fbv.fcgi%3Frid%3Dce2&amp;rfr_id=info:sid/en.wikipedia.org:Caenorhabditis_elegans"><span style="DISPLAY: none">&nbsp;</span></span> </font></li>
 
</ul>
 
</ul>
<p><a name="Online_resources" id="Online_resources"></a></p>
+
<p><font color="#000000"><a id="Online_resources" name="Online_resources"></a></font></p>
<h2><span class="editsection"></span><span class="mw-headline">Online resources</span></h2>
+
<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Online resources</font></span></h2>
 
<ul>
 
<ul>
     <li><a rel="nofollow" href="http://www.wormbase.org/" title="http://www.wormbase.org" class="external text">WormBase</a> - an extensive online database covering the biology and genomics of <em>C. elegans</em> and other nematodes </li>
+
     <li><font color="#000000">WormBase - an extensive online database covering the biology and genomics of <em>C. elegans</em> and other nematodes </font></li>
     <li><a rel="nofollow" href="http://www.wormbook.org/" title="http://www.wormbook.org/" class="external text">WormBook</a> - a free online compendium of all aspects of <em>C. elegans</em> biology, including laboratory protocols </li>
+
     <li><font color="#000000">WormBook - a free online compendium of all aspects of <em>C. elegans</em> biology, including laboratory protocols </font></li>
     <li><a rel="nofollow" href="http://www.wormatlas.org/" title="http://www.wormatlas.org" class="external text">Wormatlas</a> - an online database for behavioral and structural anatomy of <em>C. elegans</em> </li>
+
     <li><font color="#000000">Wormatlas - an online database for behavioral and structural anatomy of <em>C. elegans</em> </font></li>
     <li><a rel="nofollow" href="http://www.sanger.ac.uk/Projects/C_elegans" title="http://www.sanger.ac.uk/Projects/C_elegans" class="external text">Wellcome Trust Sanger Institute <em>C. elegans</em> page</a> - half of the genome sequence is still maintained by this institute </li>
+
     <li><font color="#000000">Wellcome Trust Sanger Institute <em>C. elegans</em> page - half of the genome sequence is still maintained by this institute </font></li>
     <li><a rel="nofollow" href="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20elegans" title="http://genome.wustl.edu/genome.cgi?GENOME=Caenorhabditis%20elegans" class="external text">WashU Genome Sequencing Center <em>C. elegans</em> page</a> - the institute maintaining the other half of the genome </li>
+
     <li><font color="#000000">WashU Genome Sequencing Center <em>C. elegans</em> page - the institute maintaining the other half of the genome </font></li>
     <li><a rel="nofollow" href="http://www.ncbi.nlm.nih.gov/IEB/Research/Acembly/index.html?worm" title="http://www.ncbi.nlm.nih.gov/IEB/Research/Acembly/index.html?worm" class="external text">AceView WormGenes</a> - another genome database for <em>C. elegans</em>, maintained at the NCBI </li>
+
     <li><font color="#000000">AceView WormGenes - another genome database for <em>C. elegans</em>, maintained at the NCBI </font></li>
     <li><a rel="nofollow" href="http://www.tcnj.edu/~nayaklab" title="http://www.tcnj.edu/~nayaklab" class="external text">TCNJ Worm Lab</a> - Easy to follow protocols and pictures for <em>C. elegans</em> research. Made by undergrads for undergrads. </li>
+
     <li><font color="#000000">TCNJ Worm Lab - Easy to follow protocols and pictures for <em>C. elegans</em> research. Made by undergrads for undergrads. </font></li>
     <li><a rel="nofollow" href="http://www.wormclassroom.org/" title="http://www.wormclassroom.org" class="external text">Worm Classroom</a> - An education portal for <em>C. elegans</em> </li>
+
     <li><font color="#000000">Worm Classroom - An education portal for <em>C. elegans</em> </font></li>
     <li><a rel="nofollow" href="http://www.textpresso.org/" title="http://www.textpresso.org/" class="external text">Textpresso</a> - WormBase search engine </li>
+
     <li><font color="#000000">Textpresso - WormBase search engine </font></li>
     <li><a rel="nofollow" href="http://www.bio.unc.edu/faculty/goldstein/lab/movies.html" title="http://www.bio.unc.edu/faculty/goldstein/lab/movies.html" class="external text"><em>C. elegans</em> movies</a> - Timelapse films made by <em>C. elegans</em> researchers worldwide </li>
+
     <li><font color="#000000"><em>C. elegans</em> movies - Timelapse films made by <em>C. elegans</em> researchers worldwide </font></li>
     <li><a rel="nofollow" href="http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&amp;rid=ce2.TOC" title="http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&amp;rid=ce2.TOC" class="external text"><em>C. elegans</em> II</a> - a free online textbook. </li>
+
     <li><font color="#000000"><em>C. elegans</em> II - a free online textbook. </font></li>
     <li><a rel="nofollow" href="http://www.silencinggenomes.org/" title="http://www.silencinggenomes.org" class="external text">Silencing Genomes</a> RNA interference (RNAi) experiments and bioinformatics in <em>C. elegans</em> for education. From the Dolan DNA Learning Center of Cold Spring Harbor Laboratory. </li>
+
     <li><font color="#000000">Silencing Genomes RNA interference (RNAi) experiments and bioinformatics in <em>C. elegans</em> for education. From the Dolan DNA Learning Center of Cold Spring Harbor Laboratory. </font></li>
     <li><a rel="nofollow" href="http://www.ciml.univ-mrs.fr/EWBANK_jonathan/3D/mainpage.html" title="http://www.ciml.univ-mrs.fr/EWBANK_jonathan/3D/mainpage.html" class="external text">C.elegans 3D model by the Ewbank Lab</a> - Videos and photos that explain the basic anatomy of <em>C. elegans</em> </li>
+
     <li><font color="#000000">C.elegans 3D model by the Ewbank Lab - Videos and photos that explain the basic anatomy of <em>C. elegans</em> </font></li>
     <li><a rel="nofollow" href="http://www.wormtracker.de/" title="http://www.wormtracker.de/" class="external text">WormTracker</a> </li>
+
     <li><font color="#000000">WormTracker </font></li>
 
</ul>
 
</ul>
<p><a name="Nobel_lectures" id="Nobel_lectures"></a></p>
+
<p><font color="#000000"><a id="Nobel_lectures" name="Nobel_lectures"></a></font></p>
<h2><span class="editsection"></span><span class="mw-headline">Nobel lectures</span></h2>
+
<h2><span class="editsection"></span><span class="mw-headline"><font color="#000000"><span class="mw-headline"><font color="#000000">C. elegans </font></span>Nobel lectures</font></span></h2>
 
<ul>
 
<ul>
     <li>Brenner S (2002) Nature's Gift to Science. In. <a rel="nofollow" href="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/brenner-lecture.pdf" title="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/brenner-lecture.pdf" class="external free">http://nobelprize.org/nobel_prizes/medicine/laureates/2002/brenner-lecture.pdf</a>   </li>
+
     <li>Brenner S (2002) Nature's Gift to Science. In. <a class="external free" title="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/brenner-lecture.pdf" rel="nofollow" href="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/brenner-lecture.pdf">http://nobelprize.org/nobel_prizes/medicine/laureates/2002/brenner-lecture.pdf</a> </li>
     <li>Horvitz HR (2002) Worms, Life and Death. In. <a rel="nofollow" href="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/horvitz-lecture.pdf" title="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/horvitz-lecture.pdf" class="external free">http://nobelprize.org/nobel_prizes/medicine/laureates/2002/horvitz-lecture.pdf</a>   </li>
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     <li>Horvitz HR (2002) Worms, Life and Death. In. <a class="external free" title="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/horvitz-lecture.pdf" rel="nofollow" href="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/horvitz-lecture.pdf">http://nobelprize.org/nobel_prizes/medicine/laureates/2002/horvitz-lecture.pdf</a> </li>
     <li>Sulston JE (2002) The Cell Lineage and Beyond. In. <a rel="nofollow" href="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/sulston-lecture.pdf" title="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/sulston-lecture.pdf" class="external free">http://nobelprize.org/nobel_prizes/medicine/laureates/2002/sulston-lecture.pdf</a> </li>
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     <li>Sulston JE (2002) The Cell Lineage and Beyond. In. <a class="external free" title="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/sulston-lecture.pdf" rel="nofollow" href="http://nobelprize.org/nobel_prizes/medicine/laureates/2002/sulston-lecture.pdf">http://nobelprize.org/nobel_prizes/medicine/laureates/2002/sulston-lecture.pdf</a> </li>
 
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     <li><a rel="nofollow" href="http://www.nytimes.com/2006/11/21/science/21find.html" title="http://www.nytimes.com/2006/11/21/science/21find.html" class="external text">Nematodes With a Craving for Nicotine</a> </li>
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Latest revision as of 04:28, 25 January 2009

Caenorhabditis elegans (pronounced /ˌsiːnoʊræbˈdaɪtɪs ˈɛlɪgænz/) is a free-living, transparent nematode (roundworm), about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model organism.[1]

C. elegans Biology

Movement of Wild-type C. elegans

C. elegans is unsegmented, vermiform, bilaterally symmetrical, with a cuticle integument, four main epidermal cords and a fluid-filled pseudocoelomate cavity. Members of the species have many of the same organ systems as other animals. In the wild, they feed on bacteria that develop on decaying vegetable matter. Individuals of C. elegans are almost all hermaphrodite, with males comprising just 0.05% of the total population on average. The basic anatomy of C. elegans includes a mouth, pharynx, intestine, gonad, and collagenous cuticle. Males have a single-lobed gonad, vas deferens, and a tail specialized for mating. Hermaphrodites have two ovaries, oviducts, spermatheca, and a single uterus.

C. elegans eggs are laid by the hermaphrodite. After hatching, they pass through four larval stages (L1-L4). When crowded or in the absence of food, C. elegans can enter an alternative third larval stage called the dauer state. Dauer larvae are stress-resistant and do not age. Hermaphrodites produce all their sperm in the L4 stage (150 sperm per gonadal arm) and then switch over to producing oocytes. The sperm are stored in the same area of the gonad as the oocytes until the first oocyte pushes the sperm into the spermatheca (a kind of chamber where the oocytes become fertilized by the sperm).[2] The male can inseminate the hermaphrodite, which will use male sperm preferentially (both types of sperm are stored in the spermatheca). When self-inseminated the wild-type worm will lay approximately 300 eggs. When inseminated by a male, the number of progeny can exceed 1,000. At 20°C, the laboratory strain of C. elegans has an average life span of approximately 2–3 weeks and a generation time of approximately 4 days. Hermaphrodites can mate with males or self-fertilize.

C. elegans has five pairs of autosomes and one pair of sex chromosomes. Sex in C. elegans is based on an X0 sex-determination system. Hermaphrodite C. elegans have a matched pair of sex chromosomes (XX); the rare males have only one sex chromosome (X0).

It is interesting to note that C. elegans is one of the only forms of life not known to have a natural virus.[3]

Longitudinal section through the hermaphrodite C. elegans.

C. elegans Laboratory uses

C. elegans is studied as a model organism for a variety of reasons. Strains are cheap to breed and can be frozen. When subsequently thawed they remain viable, allowing long-term storage. Because the complete cell lineage of the species has been determined, C. elegans has proven especially useful for studying cellular differentiation.

From a research perspective, C. elegans has the advantage of being a multicellular eukaryotic organism that is simple enough to be studied in great detail. In addition, it is transparent facilitating the study of developmental processes in the intact organism. The developmental fate of every single somatic cell (959 in the adult hermaphrodite; 1031 in the adult male) has been mapped out. These patterns of cell lineage are largely invariant between individuals, in contrast to mammals where cell development from the embryo is more largely dependent on cellular cues. In both sexes, a large number of additional cells (131 in the hermaphrodite, most of which would otherwise become neurons), are eliminated by programmed cell death (apoptosis).

Wild-type C. elegans hermaphrodite stained to highlight the nuclei of all cells

In addition, C. elegans is one of the simplest organisms with a nervous system. In the hermaphrodite, this comprises 302 neurons whose pattern of connectivity has been completely mapped out, and shown to be a small-world network.[4] Research has explored the neural mechanisms responsible for several of the more interesting behaviors shown by C. elegans, including chemotaxis, thermotaxis, mechanotransduction, and male mating behavior.

A useful feature of C. elegans is that it is relatively straightforward to disrupt the function of specific genes by RNA interference (RNAi). Silencing the function of a gene in this way can sometimes allow a researcher to infer what the function of that gene may be. The nematode can either be soaked in (or injected with) a solution of double stranded RNA, the sequence of which is complementary to the sequence of the gene that the researcher wishes to disable. Alternatively, worms can be fed on genetically transformed bacteria which express the double stranded RNA of interest.

C. elegans has also been useful in the study of meiosis. As sperm and egg nuclei move down the length of the gonad, they undergo a temporal progression through meiotic events. This progression means that every nucleus at a given position in the gonad will be at roughly the same step in meiosis, eliminating the difficulties of heterogeneous populations of cells.

The organism has also been identified as a model for nicotine dependence as it has been found to experience the same symptoms humans experience when they quit smoking.[5]

As for most model organisms, there is a dedicated online database for the species that is actively curated by scientists working in this field. The WormBase database attempts to collate all published information on C. elegans and other related nematodes. A reward of $5000 has been advertised on their website, for the finder of a new species of closely related nematode.[6] Such a discovery would broaden research opportunities with the worm.[7]

C. elegans Genome and C. elegans Genomics

C. elegans was the first multicellular organism to have its genome completely sequenced
The finished genome sequence was published in 1998,[8] although a number of small gaps were present (the last gap was finished by October 2002). The C. elegans genome sequence is approximately 100 million base pairs long and contains approximately 20,000 genes. The vast majority of these genes encode for proteins but there are likely to be as many as 1,000 RNA genes. Scientific curators continue to appraise the set of known genes, such that new gene predictions continue to be added and incorrect ones modified or removed.

In 2003, the genome sequence of the related nematode C. briggsae was also determined, allowing researchers to study the comparative genomics of these two organisms.[9] Work is now ongoing to determine the genome sequences of more nematodes from the same genus such as C. remanei,[10] C. japonica[11] and C. brenneri.[12] These newer genome sequences are being determined by using the whole genome shotgun technique which means that the resulting genome sequences are likely to not be as complete or accurate as C. elegans (which was sequenced using the 'hierarchical' or clone-by-clone approach).

The official version of the C. elegans genome sequence continues to change as and when new evidence reveals errors in the original sequencing (DNA sequencing is not an error-free process). Most changes are minor, adding or removing only a few base pairs (bp) of DNA. E.g. the WS169 release of WormBase (December 2006) lists a net gain of 6 bp to the genome sequence.[13] Occasionally more extensive changes are made, e.g. the WS159 release of May 2006 added over 300 bp to the sequence.[14]

C. elegans Evolution

It has been shown that a small number of conserved protein sequences from sponges are more similar to humans than to C. elegans.[15] This suggests that there has been an accelerated rate of evolution in the C. elegans lineage. The same study found that several phylogenetically ancient genes are not present in C. elegans.

C. elegans Scientific community

In 2002, the Nobel Prize in Physiology or Medicine was awarded to Sydney Brenner, H. Robert Horvitz and John Sulston for their work on the genetics of organ development and programmed cell death (PCD) in C. elegans. The 2006 Nobel Prize in Physiology or Medicine was awarded to Andrew Fire and Craig C. Mello, for their discovery of RNA interference in C. elegans.[16]. In 2008 Martin Chalfie shared a Nobel Prize in Chemistry for his work on green fluorescent protein (GFP) in C. elegans.

Because all research into C. elegans essentially started with Sydney Brenner in the 1970s, many scientists working in this field share a close connection to Brenner (they either worked as a post-doctoral or post-graduate researcher in Brenner's lab or in the lab of someone who previously worked with Brenner). Because most people who worked in his lab went on to establish their own worm research labs, there is now a fairly well documented 'lineage' of C. elegans scientists. This lineage was recorded in some detail at the 2003 International Worm Meeting and the results were stored in the Wormbase database.

C. elegans In the media

C. elegans made news when it was discovered that specimens had survived the Space Shuttle Columbia disaster in February 2003.[17] Later, in January 2009, it was announced that live samples of C.elegans from the University of Nottingham will spend two weeks on the International Space Station as part of a project to explore the effects of zero gravity on muscle development and its physiology. The emphasis of the research will be on the genetic basis of muscle atrophy. This has relevance to space travel, but also to individuals who are bed-ridden, geriatric or diabetic.[18]

See also about C. elegans

  • Animal testing on invertebrates

C. elegans References

  1. ^ Brenner, S. (May 1974). "The Genetics of Caenorhabditis elegans" (PDF). Genetics 77: 71–94. http://dev.wormbase.org/papers/31_Brenner74.pdf. 
  2. ^ Nayak, S., J. Goree & T. Schedl (2004). "fog-2 and the Evolution of Self-Fertile Hermaphroditism in Caenorhabditis". PLoS Biology 3 (1): e6. doi:10.1371/journal.pbio.0030006. http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0030006. 
  3. ^ Shaham S. (March 14 2006). "Worming into the cell: Viral reproduction in Caenorhabditis elegans" (PDF). Proc Natl Acad Sci USA 103 (11): 3955–56. doi:10.1073/pnas.0600779103. PMID 16537467. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1449626&blobtype=pdf. 
  4. ^ Watts D. J. & S. H. Strogatz (June 1998). "Collective dynamics of 'small-world' networks". Nature 393 (6684): 440–442. doi:10.1038/30918. http://www.nature.com/nature/journal/v393/n6684/abs/393440a0.html. 
  5. ^ Feng et al. (November 2006). "A C. elegans Model of Nicotine-Dependent Behavior: Regulation by TRP-Family Channels". Cell 127: 621–633. doi:10.1016/j.cell.2006.09.035. PMID 17081982. http://www.cell.com/content/article/abstract?uid=PIIS0092867406012955. 
  6. ^ "Caenorhabditis isolation guide". WormBase. Retrieved on 2007-08-30.
  7. ^ Dolgin, Elie (August 2007). "Slime for a dime". Science 317 (5842): 1157. doi:10.1126/science.317.5842.1157b. 
  8. ^ The C. elegans Sequencing Consortium (1998). "Genome sequence of the nematode C. elegans: a platform for investigating biology". Science 282: 2012–2018. doi:10.1126/science.282.5396.2012. PMID 9851916. http://www.sciencemag.org/cgi/content/abstract/282/5396/2012. 
  9. ^ Stein, L. D. et al. (2003). "The Genome Sequence of Caenorhabditis briggsae: A Platform for Comparative Genomics". PLoS Biology 1: 166–192. doi:10.1371/journal.pbio.0000045. 
  10. ^ Genome Sequencing Center. "Caenorhabditis remanei: Background". Washington University School of Medicine. Retrieved on 2008-07-11.
  11. ^ Genome Sequencing Center. "Caenorhabditis japonica: Background". Washington University School of Medicine. Retrieved on 2008-07-11.
  12. ^ Genome Sequencing Center. "Caenorhabditis brenneri: Background". Washington University School of Medicine. Retrieved on 2008-07-11.
  13. ^ "WormBaseWiki WS169 release notes". Wormbase. Retrieved on 2007-02-21.
  14. ^ "WormBaseWiki WS159 release notes". Wormbase. Retrieved on 2007-01-21.
  15. ^ Gamulin, V (December 2000). "Sponge proteins are more similar to those of Homo sapiens than to Caenorhabditis elegans". Biological Journal of the Linnean Society (Academic Press) 71 (4): 821–828. 
  16. ^ Fire A, Xu S, Montgomery MK, Kostas SA, Driver SE, Mello CC (February 1998). "Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans". Nature 391 (6669): 806–11. doi:10.1038/35888. PMID 9486653. 
  17. ^ "Worms survived Columbia disaster", BBC News (2003-05-01). Retrieved on 11 July 2008. 
  18. ^ http://news.bbc.co.uk/1/hi/england/nottinghamshire/7835020.stm

C. elegans Publications

  • Bird, Jean; Bird, Alan C. (1991). The structure of nematodes. Boston: Academic Press. pp. 1, 69–70, 152–153, 165, 224–225. ISBN 0-12-099651-0. 
  • Hope, Ian A. (1999). C. elegans: a practical approach. Oxford [Oxfordshire]: Oxford University Press. pp. 1–6. ISBN 0-19-963738-5. 

C. elegans Online resources

  • WormBase - an extensive online database covering the biology and genomics of C. elegans and other nematodes
  • WormBook - a free online compendium of all aspects of C. elegans biology, including laboratory protocols
  • Wormatlas - an online database for behavioral and structural anatomy of C. elegans
  • Wellcome Trust Sanger Institute C. elegans page - half of the genome sequence is still maintained by this institute
  • WashU Genome Sequencing Center C. elegans page - the institute maintaining the other half of the genome
  • AceView WormGenes - another genome database for C. elegans, maintained at the NCBI
  • TCNJ Worm Lab - Easy to follow protocols and pictures for C. elegans research. Made by undergrads for undergrads.
  • Worm Classroom - An education portal for C. elegans
  • Textpresso - WormBase search engine
  • C. elegans movies - Timelapse films made by C. elegans researchers worldwide
  • C. elegans II - a free online textbook.
  • Silencing Genomes RNA interference (RNAi) experiments and bioinformatics in C. elegans for education. From the Dolan DNA Learning Center of Cold Spring Harbor Laboratory.
  • C.elegans 3D model by the Ewbank Lab - Videos and photos that explain the basic anatomy of C. elegans
  • WormTracker

C. elegans Nobel lectures

C. elegans External links