Changes

What is a C. elegans?

136 bytes removed, 04:28, 25 January 2009

no edit summary

</div>

<h2>C. elegans Laboratory uses</h2>

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).

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]

<h2>C. elegans Genomeand Genomics</h2>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]

<h2>C. elegans Evolution</h2>

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.

<h2>C. elegans Scientific community</h2>

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.

<h2>C. elegans In the media</h2>

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]

<h2>See also about C. elegans </h2>

<ul>

<li>Animal testing on invertebrates </li>

</ul>

<h2>C. elegans References</h2>

</ol>

</div>

<h2>C. elegans Publications</h2>

<ul>

3.135.183.221

0

edits

Changes

What is a C. elegans?

Navigation menu

Views

Personal tools

Search

Tools

Related Links[Edit]