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A Transparent Window into Biology: A Primer on Caenorhabditis elegans.

Corsi AK, Wightman B, Chalfie M - Genetics (2015)

Bottom Line: We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research.Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell.These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues.

View Article: PubMed Central - PubMed

Affiliation: Biology Department, The Catholic University of America, Washington, DC 20064 corsi@cua.edu wightman@muhlenberg.edu mc21@columbia.edu.

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Life cycle of C. elegans. Animals increase in size throughout the four larval stages, but individual sexes are not easily distinguished until the L4 stage. At the L4 stage, hermaphrodites have a tapered tail and the developing vulva (white arrowhead) can be seen as a clear half circle in the center of the ventral side. The males have a wider tail (black arrowhead) but no discernible fan at this stage. In adults, the two sexes can be distinguished by the wider girth and tapered tail of the hermaphrodite and slimmer girth and fan-shaped tail (black arrowhead) of the male. Oocytes can be fertilized by sperm from the hermaphrodite or sperm obtained from males through mating. The dauer larvae are skinnier than all of the other larval stages. Photographs were taken on Petri dishes (note the bacterial lawns in all but the dauer image). Bar, 0.1 mm.
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fig2: Life cycle of C. elegans. Animals increase in size throughout the four larval stages, but individual sexes are not easily distinguished until the L4 stage. At the L4 stage, hermaphrodites have a tapered tail and the developing vulva (white arrowhead) can be seen as a clear half circle in the center of the ventral side. The males have a wider tail (black arrowhead) but no discernible fan at this stage. In adults, the two sexes can be distinguished by the wider girth and tapered tail of the hermaphrodite and slimmer girth and fan-shaped tail (black arrowhead) of the male. Oocytes can be fertilized by sperm from the hermaphrodite or sperm obtained from males through mating. The dauer larvae are skinnier than all of the other larval stages. Photographs were taken on Petri dishes (note the bacterial lawns in all but the dauer image). Bar, 0.1 mm.

Mentions: C. elegans has a rapid life cycle (3 days at 25° from egg to egg-laying adult) and exists primarily as a self-fertilizing hermaphrodite, although males arise at a frequency of <0.2% (Figure 2). These features have helped to make C. elegans a powerful model of choice for eukaryotic genetic studies. In addition, because the animal has an invariant number of somatic cells, researchers have been able to track the fate of every cell between fertilization and adulthood in live animals and to generate a complete cell lineage (Sulston and Horvitz 1977; Kimble and Hirsh 1979; Sulston et al. 1983). Researchers have also reconstructed the shape of all C. elegans cells from electron micrographs, including each of the 302 neurons of the adult hermaphrodite (White et al. 1986) and the posterior mating circuit in the adult male (Jarrell et al. 2012). These reconstructions have provided the most complete “wiring diagrams” of any nervous system and have helped to explain how sexual dimorphism affects neuronal circuits. Moreover, because of the invariant wild-type cell lineage and neuroanatomy of C. elegans, mutations that give rise to developmental and behavioral defects are readily identified in genetic screens. Finally, because C. elegans was the first multicellular organism with a complete genome sequence (C. elegans Sequencing Consortium 1998), forward and reverse genetics have led to the molecular identification of many key genes in developmental and cell biological processes.


A Transparent Window into Biology: A Primer on Caenorhabditis elegans.

Corsi AK, Wightman B, Chalfie M - Genetics (2015)

Life cycle of C. elegans. Animals increase in size throughout the four larval stages, but individual sexes are not easily distinguished until the L4 stage. At the L4 stage, hermaphrodites have a tapered tail and the developing vulva (white arrowhead) can be seen as a clear half circle in the center of the ventral side. The males have a wider tail (black arrowhead) but no discernible fan at this stage. In adults, the two sexes can be distinguished by the wider girth and tapered tail of the hermaphrodite and slimmer girth and fan-shaped tail (black arrowhead) of the male. Oocytes can be fertilized by sperm from the hermaphrodite or sperm obtained from males through mating. The dauer larvae are skinnier than all of the other larval stages. Photographs were taken on Petri dishes (note the bacterial lawns in all but the dauer image). Bar, 0.1 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492366&req=5

fig2: Life cycle of C. elegans. Animals increase in size throughout the four larval stages, but individual sexes are not easily distinguished until the L4 stage. At the L4 stage, hermaphrodites have a tapered tail and the developing vulva (white arrowhead) can be seen as a clear half circle in the center of the ventral side. The males have a wider tail (black arrowhead) but no discernible fan at this stage. In adults, the two sexes can be distinguished by the wider girth and tapered tail of the hermaphrodite and slimmer girth and fan-shaped tail (black arrowhead) of the male. Oocytes can be fertilized by sperm from the hermaphrodite or sperm obtained from males through mating. The dauer larvae are skinnier than all of the other larval stages. Photographs were taken on Petri dishes (note the bacterial lawns in all but the dauer image). Bar, 0.1 mm.
Mentions: C. elegans has a rapid life cycle (3 days at 25° from egg to egg-laying adult) and exists primarily as a self-fertilizing hermaphrodite, although males arise at a frequency of <0.2% (Figure 2). These features have helped to make C. elegans a powerful model of choice for eukaryotic genetic studies. In addition, because the animal has an invariant number of somatic cells, researchers have been able to track the fate of every cell between fertilization and adulthood in live animals and to generate a complete cell lineage (Sulston and Horvitz 1977; Kimble and Hirsh 1979; Sulston et al. 1983). Researchers have also reconstructed the shape of all C. elegans cells from electron micrographs, including each of the 302 neurons of the adult hermaphrodite (White et al. 1986) and the posterior mating circuit in the adult male (Jarrell et al. 2012). These reconstructions have provided the most complete “wiring diagrams” of any nervous system and have helped to explain how sexual dimorphism affects neuronal circuits. Moreover, because of the invariant wild-type cell lineage and neuroanatomy of C. elegans, mutations that give rise to developmental and behavioral defects are readily identified in genetic screens. Finally, because C. elegans was the first multicellular organism with a complete genome sequence (C. elegans Sequencing Consortium 1998), forward and reverse genetics have led to the molecular identification of many key genes in developmental and cell biological processes.

Bottom Line: We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research.Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell.These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues.

View Article: PubMed Central - PubMed

Affiliation: Biology Department, The Catholic University of America, Washington, DC 20064 corsi@cua.edu wightman@muhlenberg.edu mc21@columbia.edu.

Show MeSH
Related in: MedlinePlus