Caenorhabditis elegans (/ˌsiːnoʊræbˈdaɪtəs ˈɛləɡænz/)
is a free-living (not parasitic), transparent nematode (roundworm),
about 1 mm in length, that lives in temperate soil
environments. It is the type species of its genus. The name is a
blend of the Greek caeno- (recent), rhabditis (rod-like) and Latin
elegans (elegant). In 1900, Maupas initially named it Rhabditides
elegans, Osche placed it in the subgenus
Caenorhabditis in 1952, and
in 1955, Dougherty raised
Caenorhabditis to the status of genus.
C. elegans is an unsegmented pseudocoelomate and lacks respiratory or
circulatory systems. It possesses gut granules which emit a
brilliant blue fluorescence, a wave of which is seen at death in a
"death fluorescence". The majority of these nematodes are
hermaphrodites and a few are males. Males have specialised tails
for mating that include spicules.
Sydney Brenner proposed research into C. elegans primarily in
the area of neuronal development. In 1974, he began research into the
molecular and developmental biology of C. elegans, which has since
been extensively used as a model organism. It was the first
multicellular organism to have its whole genome sequenced, and as of
2012, is the only organism to have its connectome (neuronal "wiring
1.1 Microanatomy - gut granules
3.1 Embryonic development
3.1.1 Axis formation
3.2 Post-embryonic development
5 Research use
5.1 Notable findings
6.2 Other genetic studies
7 Scientific community
8 See also
10 Further reading
11 External links
Movement of wild-type C. elegans
C. elegans is unsegmented, vermiform, and bilaterally symmetrical. It
has a cuticle (a tough outer covering, as an exoskeleton), four main
epidermal cords, and a fluid-filled pseudocoelom (body cavity). It
also has some of the same organ systems as larger animals. About one
in a thousand individuals is male and the rest are hermaphrodites.
The basic anatomy of C. elegans includes a mouth, pharynx, intestine,
gonad, and collagenous cuticle. Like all nematodes, they have neither
a circulatory nor a respiratory system. The four bands of muscles that
run the length of the body are connected to a neural system that
allows the muscles to move the animal's body only as dorsal bending or
ventral bending, but not left or right, except for the head, where the
four muscle quadrants are wired independently from one another. When a
wave of dorsal/ventral muscle contractions proceeds from the back to
the front of the animal, the animal is propelled backwards. When a
wave of contractions is initiated at the front and proceeds
posteriorly along the body, the animal is propelled forwards. Because
of this dorsal/ventral bias in body bends, any normal living, moving
individual tends to lie on either its left side or its right side when
observed crossing a horizontal surface. A set of ridges on the lateral
sides of the body cuticle, the alae, are believed to give the animal
added traction during these bending motions.
The pharynx is a muscular food pump in the head of C. elegans, which
is triangular in cross-section. This grinds food and transports it
directly to the intestine. A set of "valve cells" connects the pharynx
to the intestine, but how this valve operates is not understood. After
digestion, the contents of the intestine are released via the rectum,
as is the case with all other nematodes. No direct connection
exists between the pharynx and the excretory canal, which functions in
the release of liquid urine.
Males have a single-lobed gonad, a vas deferens, and a tail
specialized for mating, which incorporates spicules. Hermaphrodites
have two ovaries, oviducts, spermatheca, and a single uterus.
Anatomical diagram of a male C. elegans
Microanatomy - gut granules
Numerous gut granules are present in the intestine of C. elegans, the
functions of which are still not fully known, as are many other
aspects of this nematode, despite the many years that it has been
studied. These gut granules are found in all of the
They are very similar to lysosomes in that they feature an acidic
interior and the capacity for endocytosis, but they are considerably
larger, reinforcing the view of their being storage organelles. A
remarkable feature of the granules is that when they are observed
under ultraviolet light, they react by emitting an intense blue
fluorescence. Another phenomenon seen is termed 'death fluorescence'.
As the worms die, a dramatic burst of blue fluorescence is emitted.
This death fluorescence typically takes place in an anterior to
posterior wave that moves along the intestine, and is seen in both
young and old worms, whether subjected to lethal injury or peacefully
dying of old age. Many theories have been posited on the functions of
the gut granules, with earlier ones being eliminated by later
findings. They are thought to store zinc as one of their functions.
Recent chemical analysis has identified the blue fluorescent material
they contain as a glycosylated form of anthranilic acid (AA). The need
for the large amounts of AA the many gut granules contain is
questioned. One possibility is that the AA is antibacterial and used
in defense against invading pathogens. Another possibility is that the
granules provide photoprotection: the bursts of AA fluorescence entail
the conversion of damaging UV light to relatively harmless visible
light. This is seen a possible link to the melanin–containing
A lateral (left) side anatomical diagram of an adult-stage C. elegans
The hermaphroditic worm is considered to be a specialized form of
self-fertile female, as its soma is female. The hermaphroditic
germline produces male gametes first, and lays eggs through its uterus
after internal fertilization. Hermaphrodites produce all their sperm
in the L4 stage (150 sperm per gonadal arm) and then produce only
oocytes. The sperm cells are stored in the same area of the gonad as
the oocytes until the first oocyte pushes the sperm into the
spermatheca (a chamber wherein the oocytes become fertilized by the
The male can inseminate the hermaphrodite, which will preferentially
use male sperm (both types of sperm are stored in the spermatheca).
Once he recognizes a hermaphrodite worm, the male nematode begins
tracing the hermaphrodite with his tail until he reaches the vulval
region. The male then probes the region with his spicules to locate
the vulva, inserts them, and releases sperm.
The sperm of C. elegans is amoeboid, lacking flagella and
acrosomes. When self-inseminated, the wild-type worm will lay
about 300 eggs. When inseminated by a male, the number of progeny can
exceed 1,000. At 20 °C, the laboratory strain of C. elegans (N2)
has an average lifespan around 2–3 weeks and a generation time
around 4 days.
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. Hermaphrodites of C. elegans have a matched pair of sex
chromosomes (XX); the rare males have only one sex chromosome (X0).
The fertilized zygote undergoes rotational holoblastic cleavage.
Sperm entry into the oocyte commences formation of an
anterior-posterior axis. The sperm microtubule organizing center
directs the movement of the sperm pronucleus to the future posterior
pole of the embryo, while also inciting the movement of PAR proteins,
a group of cytoplasmic determination factors, to their proper
respective locations. As a result of the difference in PAR protein
distribution, the first cell division is highly asymmetric. C.
elegans embryogenesis is among the best understood examples of
asymmetric cell division.
All cells of the germline arise from a single primordial germ cell,
called the P4 cell, established early in embryogenesis. This
primordial cell divides to generate two germline precursors that do
not divide further until after hatching.
The resulting daughter cells of the first cell division are called the
AB cell (containing PAR-6 and PAR-3) and the P1 cell (containing PAR-1
and PAR-2). A second cell division produces the ABp and ABa cells from
the AB cell, and the EMS and P2 cells from the P1 cell. This division
establishes the dorsal-ventral axis, with the ABp cell forming the
dorsal side and the EMS cell marking the ventral side. Through Wnt
signaling, the P2 cell instructs the EMS cell to divide along the
anterior-posterior axis. Through Notch signaling, the P2 cell
differentially specifies the ABp and ABa cells, which further defines
the dorsal-ventral axis. The left-right axis also becomes apparent
early in embryogenesis, although it is unclear exactly when
specifically the axis is determined. However, most theories of the L-R
axis development involve some kind of differences in cells derived
from the AB cell.
Gastrulation occurs after the embryo reaches the 26-cell stage. C.
elegans are a species of protostomes, so the blastopore eventually
forms the mouth. Involution into the blastopore begins with movement
of the endoderm cells and subsequent formation of the gut, followed by
the P4 germline precursor, and finally the mesoderm cells, including
the cells that eventually form the pharynx. Gastrulation ends when
epiboly of the hypoblasts closes the blastopore.
Under environmental conditions favourable for reproduction, hatched
larvae develop through four larval stages-L1,L2,L3, and L4. When
conditions are stressed, as in food insufficiency, C. elegans can
enter an alternative third larval stage called the dauer stage (Dauer
is German for permanent). Dauer larvae are stress-resistant; they are
thin and their mouths are sealed and cannot take in food, and they can
remain in this stage for a few months.
Each stage transition is punctuated by a molt of the worm's
transparent cuticle. Transitions through these stages is controlled by
genes of the heterochronic pathway, an evolutionarily conserved set of
regulatory factors. Many heterochronic genes code for microRNAs,
which repress the expression of heterochronic transcription factors
and other heterochronic miRNAs. miRNAs were originally discovered
in C. elegans. Important developmental events controlled by
heterochronic genes include the division and eventual syncitial fusion
of the hypodermic seam cells, and their subsequent secretion of the
alae in young adults. It is believed that the heterochronic pathway
represents an evolutionarily conserved predecessor to circadian
Nematodes have a fixed, genetically determined number of cells, a
phenomenon known as eutely. The adult hermaphrodite has exactly 959
cells. The male C. elegans has 1031 cells. The number of cells does
not change after cell division ceases at the end of the larval period,
and subsequent growth is due solely to an increase in the size of
Main article: Host microbe interactions in
Caenorhabditis species occupy various nutrient- and
bacteria-rich environments. They feed on the bacteria that develop in
decaying organic matter (microbivory). Soil lacks enough organic
matter to support self-sustaining populations. C. elegans can survive
on a diet of a variety of bacteria, but its wild ecology is largely
unknown. Most laboratory strains were taken from artificial
environments such as gardens and compost piles. More recently, C.
elegans has been found to thrive in other kinds of organic matter,
particularly rotting fruit.
C. elegans can also use different species of yeast, including
Cryptococcus laurentii and Cryptococcus kuetzingii, as sole source of
food. Although a bacterivore, C. elegans can be killed by a number
of pathogenic bacteria, including human pathogens such as
Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella
enterica or Enterococcus faecalis.
Invertebrates such as millipedes, insects, isopods, and gastropods can
transport dauer larvae to various suitable locations. The larvae have
also been seen to feed on their hosts when they die.
Nematodes can survive desiccation, and in C. elegans, the mechanism
for this capability has been demonstrated to be late embryogenesis
C. elegans, as other nematodes, can be eaten by predator nematodes and
other omnivores, including some insects.
Orsay virus is a virus that affects C. elegans, as well as the
Caenorhabditis elegans Cer1 virus and the
Interactions with fungi
Wild isolates of
Caenorhabditis elegans are regularly found with
Microsporidia fungi. One such species, Nematocida
parisii, replicates in the intestines of C. elegans.
Arthrobotrys oligospora is the model organism for interactions between
fungi and nematodes. It is the most common nematode capturing
fungus, and most widespread nematode trapping fungus in nature.
Further information: History of research on
Asymmetric cell divisions during early embryogenesis of wild-type C.
Sydney Brenner proposed using C. elegans as a model organism
for the investigation primarily of neural development in animals. It
is one of the simplest organisms with a nervous system. The neurons do
not fire action potentials, and do not express any voltage-gated ion
channels. In the hermaphrodite, this system comprises 302
neurons the pattern of which has been comprehensively mapped, in
what is known as a connectome, and shown to be a small-world
network. Research has explored the neural and molecular mechanisms
that control several behaviors of C. elegans, including chemotaxis,
thermotaxis, mechanotransduction, learning, memory, and mating
behaviour. Brenner also chose it as it is easy to grow in bulk
populations, and convenient for genetic analysis. It is a
multicellular eukaryotic organism, yet is simple enough to be studied
in great detail. The transparency of C. elegans facilitates the study
of cellular differentiation and other developmental processes in the
intact organism. The spicules in the male clearly distinguish males
from females. Strains are cheap to breed and can be frozen. When
subsequently thawed, they remain viable, allowing long-term
storage. Maintenance is easy when compared to other multicellular
model organisms, a few hundred nematodes can be kept on a single agar
plate and suitable growth medium. Brenner described the use of a
mutant of E. Coli – OP50. OP50 is a uracil-requiring organism and
its deficiency in the plate prevents the overgrowth of bacteria which
would obscure the worms.
The developmental fate of every single somatic cell (959 in the adult
hermaphrodite; 1031 in the adult male) has been mapped. These
patterns of cell lineage are largely invariant between individuals,
whereas in mammals, cell development is more dependent on cellular
cues from the embryo.
As mentioned previously, the first cell divisions of early
embryogenesis in C. elegans are among the best understood examples of
asymmetric cell divisions, and the worm is a very popular model system
for studying developmental biology.
Programmed cell death (apoptosis) eliminates many additional cells
(131 in the hermaphrodite, most of which would otherwise become
neurons); this "apoptotic predictability" has contributed to the
elucidation of some apoptotic genes. Cell death-promoting genes and a
single cell-death inhibitor have been identified.
Wild-type C. elegans hermaphrodite stained with the fluorescent dye
Texas Red to highlight the nuclei of all cells
RNA interference (RNAi) is a relatively straightforward method of
disrupting the function of specific genes. Silencing the function of a
gene can sometimes allow a researcher to infer its possible
function(s). The nematode can be soaked in, injected with, or fed with
genetically transformed bacteria that express the double-stranded RNA
of interest, the sequence of which complements the sequence of the
gene that the researcher wishes to disable. RNAi has emerged as a
powerful tool in the study of functional genomics. In C. elegans, it
has been used to analyse gene functions and the report claims the
promise of future findings in the systematic genetic interactions.
Environmental RNAi uptake is much worse in other species of worms in
Caenorhabditis genus. Although injecting RNA into the body cavity
of the animal induces gene silencing in most species, only C. elegans
and a few other distantly related nematodes can take up RNA from the
bacteria they eat for RNAi. This ability has been mapped down to a
single gene, sid-2, which, when inserted as a transgene in other
species, allows them to take up RNA for RNAi as C. elegans does.
Research into meiosis has been considerably simplified since every
germ cell nucleus is at the same given position as it moves down the
gonad, so is at the same stage in meiosis. In an early phase of
meiosis, the oocytes become extremely resistant to radiation and this
resistance depends on expression of genes rad51 and atm that have key
roles in recombinational repair.
Gene mre-11 also plays a
crucial role in recombinational repair of DNA damage during
meiosis. A study of the frequency of outcrossing in natural
populations showed that selfing is the predominant mode of
reproduction in C. elegans, but that infrequent outcrossing events
occur at a rate around 1%. Meioses that result in selfing are
unlikely to contribute significantly to beneficial genetic
variability, but these meioses may provide the adaptive benefit of
recombinational repair of DNA damages that arise, especially under
Nicotine dependence can also be studied using C. elegans because it
exhibits behavioral responses to nicotine that parallel those of
mammals. These responses include acute response, tolerance,
withdrawal, and sensitization.
As for most model organisms, scientists that work in the field curate
a dedicated online database and the
WormBase is that for C. elegans.
WormBase attempts to collate all published information on C.
elegans and other related nematodes. Their website has advertised a
reward of $4000 for the finder of a new species of closely related
nematode. Such a discovery would broaden research opportunities
with the worm.
C. elegans has been a model organism for research into ageing; for
example, the inhibition of an insulin-like growth factor signaling
pathway has been shown to increase adult lifespan threefold.
C. elegans has been instrumental to identify the functions of genes
implicated in Alzheimer's disease, such as presenilin. Moreover,
extensive research on C. elegans has identified RNA-binding proteins
as essential factors during germline and early embryonic
C. elegans is notable in animal sleep studies as the most primitive
organism to display sleep-like states. In C. elegans, a lethargus
phase occurs shortly before each moult.
Even if the worm has no eyes, it has been revealed it is sensitive to
light due to a third type of photoreceptors that is 10 to 100 times
better to absorb light than the other two types of photoreceptors
found in the animal kingdom.
C. elegans made news when specimens were discovered to have survived
Space Shuttle Columbia disaster
Space Shuttle Columbia disaster in February 2003. Later, in
January 2009, live samples of C. elegans from the University of
Nottingham were announced to be spending two weeks on the
International Space Station
International Space Station that October, in a space research project
to explore the effects of zero gravity on muscle development and
physiology. The research was primarily about genetic basis of muscle
atrophy, which relates to spaceflight or being bed-ridden, geriatric,
or diabetic. Descendants of the worms aboard Columbia in 2003 were
launched into space on Endeavour for the
Additional experiments on muscle dystrophy during spaceflight will be
carried on starting in November 2018 on board the ISS.
Karyotype of C. elegans
explanation of colors
Mitotic chromosomes of
Caenorhabditis elegans. DNA (red)/ Kinetochores
(green). Holocentric organisms, including C. elegans, assemble diffuse
kinetochores along the entire poleward face of each sister chromatid.
NCBI genome ID
Number of chromosomes
5 pairs of autosomes (I, II, III, IV and V) + 1 or 2 sex chromosomes
Year of completion
C. elegans hermaphrodite
C. elegans was the first multicellular organism to have its whole
genome sequenced. The sequence was published in 1998, although
some small gaps were present; the last gap was finished by October
Size and gene content. The C. elegans genome is about 100 million base
pairs long and consists of six chromosomes and a mitochondrial genome.
Its gene density is about one gene per five kilo-base pairs. Introns
make up 26% and intergenic regions 47% of the genome. Many genes are
arranged in clusters and how many of these are operons is unclear.
C. elegans and other nematodes are among the few eukaryotes currently
known to have operons; these include trypanosomes, flatworms (notably
the trematode Schistosoma mansoni), and a primitive chordate tunicate
Oikopleura dioica. Many more organisms are likely to be shown to have
Protein-coding genes. The genome contains an estimated 20,470
protein-coding genes. About 35% of C. elegans genes have human
homologs. Remarkably, human genes have been shown repeatedly to
replace their C. elegans homologs when introduced into C. elegans.
Conversely, many C. elegans genes can function similarly to mammalian
genes. The number of known RNA genes in the genome has increased
greatly due to the 2006 discovery of a new class of
and the genome is now believed to contain more than 16,000 RNA genes,
up from as few as 1,300 in 2005. Scientific curators continue to
appraise the set of known genes; new gene models continue to be added
and incorrect ones modified or removed.
The reference C. elegans genome sequence continues to change as new
evidence reveals errors in the original sequencing. Most changes are
minor, adding or removing only a few base pairs of DNA. For example,
the WS202 release of
WormBase (April 2009) added two base pairs to the
genome sequence. Sometimes, more extensive changes are made as
noted in the WS197 release of December 2008, which added a region of
over 4,300 bp to the sequence.
Related genomes. 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. The genome sequences
of more nematodes from the same genus e.g., C. remanei, C.
japonica and C. brenneri (named after Brenner), have also been
studied using the shotgun sequencing technique. These sequences
have now been completed.
Other genetic studies
C. elegans adult with GFP coding sequence inserted into a
histone-encoding gene by Cas9-triggered homologous recombination
As of 2014, C. elegans is the most basal species in the 'Elegans'
group (10 species) of the 'Elegans' supergroup (17 species) in
phylogenetic studies. It forms a branch of its own distinct to any
other species of the group.
Tc1 transposon is a DNA transposon active in C. elegans.
In 2002, the
Nobel Prize in Physiology or Medicine
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 in C.
elegans. The 2006
Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine was awarded to
Andrew Fire and
Craig C. Mello
Craig C. Mello for their discovery of RNA interference
in C. elegans. In 2008,
Martin Chalfie shared a Nobel Prize in
Chemistry for his work on green fluorescent protein; some of the
research involved the use of C. elegans.
Many scientists who research C. elegans closely connect to Sydney
Brenner, with whom almost all research in this field began in the
1970s; they have worked as either a postdoctoral or a postgraduate
researcher in Brenner's lab or in the lab of someone who previously
worked with Brenner. Most who worked in his lab later established
their own worm research labs, thereby creating a fairly
well-documented "lineage" of C. elegans scientists, which was recorded
WormBase database in some detail at the 2003 International
Wikimedia Commons has media related to
Animal testing on invertebrates
^ Maupas, É (1900). "Modes et formes de reproduction des nématodes".
Archives de Zoologie Expérimentale et Générale. 8: 463–624.
^ Les modalités de la reproduction et le déterminisme du sexe chez
quelques nematodes libres. Nigon V. Ann. Sci. Nat. Zool. Biol. Anim.
^ Moerman, D. G.; Waterston, R. H. (1984). "Spontaneous Unstable
UNC-22 IV Mutations in C. ELEGANS Var. Bergerac". Genetics. 108 (4):
859–877. PMC 1224270 . PMID 6096205.
^ Tc1 transposition and mutator activity in a
Bristol strain of
Caenorhabditis elegans. Babity JM, Starr TV and Rose AM, Mol Gen
Genet., 1990 June, 222(1), pages 65-70, PMID 1978238
^ Structural analysis of Tc1 elements in
Caenorhabditis elegans var.
Bristol (strain N2). Harris LJ and Rose AM, Plasmid. 1989 Jul;22(1),
page 10-21, PMID 2550981
^ Wood, WB (1988). The
Caenorhabditis elegans. Cold Spring
Harbor Laboratory Press. p. 1. ISBN 0-87969-433-5.
^ Sudhaus, W.; Kiontke, K. (2009). "Phylogeny of Rhabditis subgenus
Caenorhabditis (Rhabditidae, Nematoda)". Journal of Zoological
Systematics and Evolutionary Research. 34 (4): 217.
^ καινός (caenos) = new, recent; ῥάβδος (rhabdos) = rod,
^ Ferris, H (30 November 2013). "
Caenorhabditis elegans". University
of California, Davis. Archived from the original on 9 December 2013.
^ Wallace, R. L; Ricci, C; Melone, G (1996). "A cladistic analysis of
pseudocoelomate (aschelminth) morphology". Invertebrate Biology:
^ Coburn, Cassandra; Allman, Erik; Mahanti, Parag; Benedetto,
Alexandre; Cabreiro, Filipe; Pincus, Zachary; Matthijssens, Filip;
Araiz, Caroline; Mandel, Abraham; Vlachos, Manolis; Edwards,
Sally-Anne; Fischer, Grahame; Davidson, Alexander; Pryor, Rosina E.;
Stevens, Ailsa; Slack, Frank J.; Tavernarakis, Nektarios; Braeckman,
Bart P.; Schroeder, Frank C.; Nehrke, Keith; Gems, David (2013).
Fluorescence Marks a Calcium-Propagated Necrotic Wave
That Promotes Organismal Death in C. Elegans". PLoS Biology. 11 (7):
e1001613. doi:10.1371/journal.pbio.1001613. PMC 3720247 .
^ "Introduction to sex determination". www.wormbook.org. Retrieved
^ Brenner, S (1974). "The
Genetics. 77 (1): 71–94. PMC 1213120 .
^ White, J. G.; Southgate, E.; Thomson, J. N.; Brenner, S. (1986).
"The Structure of the Nervous System of the
elegans". Philosophical Transactions of the Royal Society B:
Biological Sciences. 314 (1165): 1. Bibcode:1986RSPTB.314....1W.
^ White, John G. (2013). "Getting into the mind of a worm—a personal
view". WormBook: 1. doi:10.1895/wormbook.1.158.1.
^ Jabr, Ferris (2012-10-02). "The
Connectome Debate: Is Mapping the
Mind of a Worm Worth It?". Scientific American. Retrieved
^ Alberts, B; Johnson, A; Lewis, J; Raff, M; Roberts, K; Walter, P
(2007). Molecular Biology of the Cell (5th ed.). Garland Science.
p. 1321. ISBN 978-0-8153-4105-5.
^ "The C. elegans pharynx: a model for organogenesis".
www.wormbook.org. Retrieved 2017-03-15.
^ Coburn, C; Gems, D (2013). "The mysterious case of the C. Elegans
gut granule: Death fluorescence, anthranilic acid and the kynurenine
pathway". Frontiers in Genetics. 4: 151. doi:10.3389/fgene.2013.00151.
PMC 3735983 . PMID 23967012.
^ Nayak, S; Goree, J; Schedl, T (2004). "fog-2 and the Evolution of
Self-Fertile Hermaphroditism in Caenorhabditis". PLoS Biology. 3 (1):
e6. doi:10.1371/journal.pbio.0030006. PMC 539060 .
^ Loer, C. M.; Kenyon, C. J. (1993-12-01). "Serotonin-deficient
mutants and male mating behavior in the nematode Caenorhabditis
elegans". The Journal of Neuroscience. 13 (12): 5407–5417.
^ Ma, X.; Zhao, Y; et al. (Oct 2012). "Transformation: how do nematode
sperm become activated and crawl?".
Protein Cell. 3 (3 (10)):
755–61. doi:10.1007/s13238-012-2936-2. PMC 4875351 .
^ Gilbert SF (2016).
Developmental biology (11th ed.). Sinauer.
p. 268. ISBN 9781605354705. PMID 7758115
^ Guo S, Kemphues KJ (1995). "par-1, a gene required for establishing
polarity in C. elegans embryos, encodes a putative Ser/Thr kinase that
is asymmetrically distributed". Cell. 81 (4): 611–20.
doi:10.1016/0092-8674(95)90082-9. PMID 7758115.
^ a b Gönczy, P (2005). "
Asymmetric cell division
Asymmetric cell division and axis formation
in the embryo". WormBook: 1–20. doi:10.1895/wormbook.1.30.1.
^ Kimble J, Crittenden SL.
Germline proliferation and its control.
2005 Aug 15. In: WormBook: The Online Review of C. elegans Biology
[Internet]. Pasadena (CA): WormBook; 2005-. Available from:
^ a b "WBbt:0006773 (anatomy term)".
WormBase (WS242 ed.). May 14,
^ Gilbert SF (2016).
Developmental biology (11th ed.). Sinauer.
p. 272. ISBN 9781605354705.
^ Thorpe CJ, Schlesinger A, Carter JC, Bowerman B (1997). "Wnt
signaling polarizes an early C. elegans blastomere to distinguish
endoderm from mesoderm". Cell. 90 (4): 695–705.
doi:10.1016/s0092-8674(00)80530-9. PMID 9288749. CS1 maint:
Multiple names: authors list (link)
^ Pohl, Christian; Bao, Zhirong (September 2010). "Chiral Forces
Organize Left-Right Patterning in C. elegans by Uncoupling Midline and
Anteroposterior Axis". Developmental Cell. 19 (3): 402–412.
doi:10.1016/j.devcel.2010.08.014. PMC 2952354 .
PMID 20833362. PMID 3073266 Gilbert SF (2016).
Developmental biology (11th ed.). Sinauer. p. 269.
^ Skiba F, Schierenberg E (1992). "Cell lineages, developmental
timing, and spatial pattern formation in embryos of free-living soil
nematodes". Dev Biol. 151 (2): 597–610.
doi:10.1016/0012-1606(92)90197-o. PMID 1601187.
^ Gilbert SF (2016).
Developmental biology (11th ed.). Sinauer.
p. 273. ISBN 9781605354705.
^ a b "Introduction to C. Elegans". C. Elegans as a model organism.
Rutgers University. Archived from the original on 2002-08-18.
Retrieved August 15, 2014.
^ Resnick TD, McCulloch KA, Rougvie AE (2010). "miRNAs give worms the
time of their lives: small RNAs and temporal control in Caenorhabditis
elegans". Dev Dyn. 239 (5): 1477–89. doi:10.1002/dvdy.22260.
PMC 4698981 . PMID 20232378. CS1 maint: Multiple
names: authors list (link)
^ Rougvie AE, Moss EG (2013). "Developmental transitions in C. elegans
larval stages". Curr Top Dev Biol. 105: 153–80.
doi:10.1016/B978-0-12-396968-2.00006-3. PMID 23962842.
^ Lee RC, Feinbaum RL, Ambros V (1993). "The C. elegans heterochronic
gene lin-4 encodes small RNAs with antisense complementarity to
lin-14". Cell. 75 (5): 843–54. doi:10.1016/0092-8674(93)90529-y.
PMID 8252621. CS1 maint: Multiple names: authors list (link)
^ Banerjee D, Kwok A, Lin SY, Slack FJ (2005). "Developmental timing
in C. elegans is regulated by kin-20 and tim-1, homologs of core
circadian clock genes". Dev Cell. 8 (2): 287–95.
doi:10.1016/j.devcel.2004.12.006. PMID 15691769. CS1 maint:
Multiple names: authors list (link)
^ Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).
Invertebrate Zoology (7th ed.). Cengage Learning. p. 753.
^ Félix, MA; Braendle, C (2010). "The natural history of
Caenorhabditis elegans". Current Biology. 20 (22): R965–R969.
doi:10.1016/j.cub.2010.09.050. PMID 21093785.
^ Killing of
Caenorhabditis elegans by Cryptococcus neoformans as a
model of yeast pathogenesis. Eleftherios Mylonakis, Frederick M.
Ausubel, John R. Perfect, Joseph Heitman and Stephen B. Calderwood,
PNAS 2002 November, 99 (24) 15675-15680, doi:10.1073/pnas.232568599
Caenorhabditis elegans as a Model Host for Staphylococcus aureus
Pathogenesis. Costi D. Sifri, Jakob Begun, Frederick M. Ausubel and
Stephen B. Calderwood, Infect Immun., 2003 Apr, 71(4), pages
2208–2217, doi:10.1128/IAI.71.4.2208-2217.2003, PMC 152095
^ Killing of
Caenorhabditis elegans by
Pseudomonas aeruginosa used to
model mammalian bacterial pathogenesis. Man-Wah Tan, Shalina
Mahajan-Miklos and Frederick M. Ausubel, PNAS, 1999 January, 96 (2),
pages 715-720, doi:10.1073/pnas.96.2.715
^ Long-Lived C. elegans daf-2 Mutants Are Resistant to Bacterial
Pathogens. Danielle A. Garsin, Jacinto M. Villanueva, Jakob Begun,
Dennis H. Kim, Costi D. Sifri, Stephen B. Calderwood, Gary Ruvkun and
Frederick M. Ausubel1, Science, 20 Jun 2003, Vol. 300, Issue 5627,
page 1921, doi:10.1126/science.1080147
^ Kiontke, K; Sudhaus, W (2006). "Ecology of
WormBook: 1–14. doi:10.1895/wormbook.1.37.1. PMC 4780885 .
^ Gal, TZ; Glazer, I; Koltai, H (2004). "An LEA group 3 family member
is involved in survival of C. elegans during exposure to stress". FEBS
Letters. 577 (1–2): 21–26. doi:10.1016/j.febslet.2004.09.049.
^ Elaine R. Ingham Soil biology primer USDA
^ Genomic Analysis of
Caenorhabditis elegans Reveals Ancient Families
of Retroviral-like Elements. Nathan J. Bowen and John F. McDonald,
Genome Res., 1999, 9, pages 924-935, doi:10.1101/gr.9.10.924
^ Cuomo, C. A.; Desjardins, C. A.; Bakowski, M. A.; Goldberg, J.; Ma,
A. T.; Becnel, J. J.; Didier, E. S.; Fan, L.; Heiman, D. I.; Levin, J.
Z.; Young, S.; Zeng, Q.; Troemel, E. R. (2012). "Microsporidian genome
analysis reveals evolutionary strategies for obligate intracellular
growth". Genome Research. 22 (12): 2478. doi:10.1101/gr.142802.112.
PMC 3514677 . PMID 22813931.
^ Niu, Xue-Mei; Zhang, Ke-Qin (2011). "
Arthrobotrys oligospora a model
organism for understanding the interaction between fungi and
nematodes". Mycology. 2 (2): 59–78. doi:10.1080/21501203.2011.562559
^ Clare, Jeffrey J.; Tate, Simon N.; Nobbs, Malcolm; Romanos, Mike A.
(2000). "Voltage-gated sodium channels as therapeutic targets". Drug
Discovery Today. 5 (11): 506. doi:10.1016/S1359-6446(00)01570-1.
^ Kosinski, R. A.; Zaremba, M. (2007). "Dynamics of the Model of the
Caenorhabditis Elegans Neural Network". Acta Physica Polonica B. 38:
^ Watts, Duncan J.; Strogatz, Steven H. (1998). "Collective dynamics
of 'small-world' networks". Nature. 393 (6684): 440.
^ Schafer, William R. (2005). "Deciphering the Neural and Molecular
Mechanisms of C. Elegans Behavior". Current Biology. 15 (17):
R723–9. doi:10.1016/j.cub.2005.08.020. PMID 16139205.
^ Avery, L. "Sydney Brenner". Southwestern Medical Center. Archived
from the original on August 15, 2011. Alt. URL
^ Brenner, S (1974). "The
Genetics. 77 (1): 71–94. PMC 1213120 .
^ Brenner, S (1974). "The genetics of
Genetics. 77: 71.
^ Sulston, JE; Horvitz, HR (1977). "Post-embryonic cell lineages of
Caenorhabditis elegans". Developmental Biology. 56 (1):
110–56. doi:10.1016/0012-1606(77)90158-0. PMID 838129.
^ Kimble, J; Hirsh, D (1979). "The postembryonic cell lineages of the
hermaphrodite and male gonads in
Developmental Biology. 70 (2): 396–417.
doi:10.1016/0012-1606(79)90035-6. PMID 478167.
^ Peden, E (Aug 2008). "Cell death specification in C. elegans". Cell
Cycle. 7 (16): 2479–2484. doi:10.4161/cc.7.16.6479.
PMC 2651394 . PMID 18719375.
^ Kamath, RS; et al. (2003). "Systematic functional analysis of the
Caenorhabditis elegans genome using RNAi". Nature. 421 (6920):
231–237. Bibcode:2003Natur.421..231K. doi:10.1038/nature01278.
^ Fortunato, AI & Fraser, AG (2005). "Uncover genetic interaction
Caenorhabditis elegans by RNA interference". Biosci Rep. 25
(Oct-Dec (5-6)): 299–307. doi:10.1007/s10540-005-2892-7.
^ Félix, M-A (2008). "
RNA interference in nematodes and the chance
that favored Sydney Brenner". Journal of Biology. 7 (9): 34–56.
doi:10.1186/jbiol97. PMC 2776389 . PMID 19014674.
^ Winston, WM; Sutherlin, M; Wright, AJ; Feinberg, EH; Hunter, CP
Caenorhabditis elegans SID-2 is required for environmental
RNA interference". Proceedings of the National Academy of Sciences.
104 (25): 10565–70. Bibcode:2007PNAS..10410565W.
doi:10.1073/pnas.0611282104. PMC 1965553 .
^ Takanami, T.; Mori, A; Takahashi, H; Higashitani, A (2000).
"Hyper-resistance of meiotic cells to radiation due to a strong
expression of a single recA-like gene in
Nucleic Acids Research. 28 (21): 4232–6. doi:10.1093/nar/28.21.4232.
PMC 113154 . PMID 11058122.
^ Takanami, Takako; Zhang, Yongzhao; Aoki, Hidetoshi; Abe, Tomoko;
Yoshida, Shigeo; Takahashi, Hideyuki; Horiuchi, Saburo; Higashitani,
Atsushi (2003). "Efficient Repair of DNA Damage Induced by Heavy Ion
Particles in Meiotic Prophase I Nuclei of
Journal of Radiation Research. 44 (3): 271. doi:10.1269/jrr.44.271.
^ Chin, G. M. (2001). "C. Elegans mre-11 is required for meiotic
recombination and DNA repair but is dispensable for the meiotic G2 DNA
damage checkpoint". Genes & Development. 15 (5): 522.
^ Barrière, Antoine; Félix, Marie-Anne (2005). "High Local Genetic
Diversity and Low Outcrossing Rate in
Caenorhabditis elegans Natural
Populations". Current Biology. 15 (13): 1176.
doi:10.1016/j.cub.2005.06.022. PMID 16005289.
^ Bernstein H and Bernstein C (2013). Evolutionary Origin and Adaptive
Function of Meiosis. In Meiosis: Bernstein C and Bernstein H, editors.
ISBN 978-953-51-1197-9, InTech,
^ Feng, Zhaoyang; Li, Wei; Ward, Alex; Piggott, Beverly J.; Larkspur,
Erin R.; Sternberg, Paul W.; Xu, X.Z. Shawn (2006). "A C. Elegans
Model of Nicotine-Dependent Behavior: Regulation by TRP-Family
Channels". Cell. 127 (3): 621. doi:10.1016/j.cell.2006.09.035.
PMC 2859215 . PMID 17081982.
Caenorhabditis isolation guide". WormBase. Archived from the
original on November 7, 2007. Retrieved 2007-08-30. Alt. URL
^ Dolgin, E. (2007). "Slime for a Dime". Science. 317 (5842): 1157b.
^ Wolkow, C. A.; Kimura, Koutarou D.; Lee, Ming-Sum; Ruvkun, Gary
(2000). "Regulation of C. Elegans Life-Span by Insulinlike Signaling
in the Nervous System". Science. 290 (5489): 147.
^ Ewald, Collin Y.; Landis, Jess N.; Abate, Jess Porter; Murphy,
Coleen T.; Blackwell, T. Keith (2015). "Dauer-independent
insulin/IGF-1-signalling implicates collagen remodelling in
longevity". Nature. 519 (7541): 97–101. doi:10.1038/nature14021.
^ Ewald, Collin Y.; Li, Chris (2010-03-01). "Understanding the
molecular basis of
Alzheimer's disease using a
model system". Brain Structure and Function. 214 (2–3): 263–283.
doi:10.1007/s00429-009-0235-3. ISSN 1863-2653.
^ Hanazawa, Momoyo; Yonetani, Masafumi; Sugimoto, Asako (2011). "PGL
proteins self associate and bind RNPs to mediate germ granule assembly
inC. Elegans". The Journal of Cell Biology. 192 (6): 929.
doi:10.1083/jcb.201010106. PMC 3063142 .
^ Iwanir, S.; Tramm, N.; et al. (Mar 2013). "The microarchitecture of
C. elegans behavior during lethargus: homeostatic bout dynamics, a
typical body posture, and regulation by a central neuron". Sleep. 36
(3): 385–95. doi:10.5665/Sleep.2456. PMC 3571756 .
^ Teensy, Eyeless Worms Have Completely New Light-Detecting Cells
^ "Worms survived Columbia disaster". BBC News. 1 May 2003. Retrieved
^ "University sends worms into space". BBC News. 17 January 2009.
^ Klotz, I (16 May 2011). "Legacy Space Worms Flying on Shuttle".
Discovery News. Retrieved 2011-05-17.
^ Space muscles study to use tiny worms. BBC News. 5 April 2015.
^ Regulation of the X Chromosomes in
Caenorhabditis elegans. Susan
Strome, William G. Kelly, Sevinc Ercan and Jason D. Lieb, Cold Spring
Harb Perspect Biol., 2014 Marh, 6(3), a018366.,
doi:10.1101/cshperspect.a018366, PMC 3942922
^ The C. elegans Sequencing Consortium (1998). "Genome sequence of the
nematode C. elegans: A platform for investigating biology". Science.
282 (5396): 2012–2018. doi:10.1126/science.282.5396.2012.
^ Blumenthal, Thomas; Evans, Donald; Link, Christopher D.; Guffanti,
Alessandro; Lawson, Daniel; Thierry-Mieg, Jean; Thierry-Mieg,
Danielle; Chiu, Wei Lu; Duke, Kyle; Kiraly, Moni; Kim, Stuart K.
(2002). "A global analysis of
Caenorhabditis elegans operons". Nature.
417 (6891): 851. Bibcode:2002Natur.417..851B. doi:10.1038/nature00831.
^ Blumenthal, T (2004). "Operons in eukaryotes". Briefings in
Functional Genomics and Proteomics. 3 (3): 199–211.
doi:10.1093/bfgp/3.3.199. PMID 15642184.
^ "WS227 Release Letter". WormBase. 10 August 2011. Retrieved
^ Ruby, JG; Jan, C; Player, C; Axtell, MJ; Lee, W; Nusbaum, C; Ge, H;
Bartel, DP (2006). "Large-scale Sequencing Reveals 21U-RNAs and
Additional MicroRNAs and Endogenous siRNAs in C. elegans". Cell. 127
(6): 1193–207. doi:10.1016/j.cell.2006.10.040.
^ Stricklin, SL; Griffiths-Jones, S; Eddy, SR (2005). "C. elegans
noncoding RNA genes". WormBook: 1–7. doi:10.1895/wormbook.1.1.1.
PMC 4781554 . PMID 18023116.
^ "WS202 Release Letter". WormBase. 29 May 2009. Retrieved
^ "WS197 Release Letter". WormBase. 27 November 2008. Retrieved
^ "Genome sequence changes". WormBase. 15 June 2011. Retrieved
^ Stein, Lincoln D; Bao, Zhirong; Blasiar, Darin; Blumenthal, Thomas;
Brent, Michael R; Chen, Nansheng; Chinwalla, Asif; Clarke, Laura;
Clee, Chris; Coghlan, Avril; Coulson, Alan; d'Eustachio, Peter; Fitch,
David H. A; Fulton, Lucinda A; Fulton, Robert E; Griffiths-Jones, Sam;
Harris, Todd W; Hillier, Ladeana W; Kamath, Ravi; Kuwabara, Patricia
E; Mardis, Elaine R; Marra, Marco A; Miner, Tracie L; Minx, Patrick;
Mullikin, James C; Plumb, Robert W; Rogers, Jane; Schein, Jacqueline
E; Sohrmann, Marc; et al. (2003). "The Genome Sequence of
Caenorhabditis briggsae: A Platform for Comparative Genomics". PLoS
Biology. 1 (2): e45. doi:10.1371/journal.pbio.0000045.
PMC 261899 . PMID 14624247.
^ Genome Sequencing Center. "
Caenorhabditis remanei: Background".
Washington University School of Medicine. Archived from the original
on 2008-06-16. Retrieved 2008-07-11.
^ Genome Sequencing Center. "
Caenorhabditis japonica: Background".
Washington University School of Medicine. Archived from the original
on 2008-06-26. Retrieved 2008-07-11.
^ Staden, R. (1979). "A strategy of DNA sequencing employing computer
programs". Nucleic Acids Research. 6 (7): 2601–10.
doi:10.1093/nar/6.7.2601. PMC 327874 . PMID 461197.
^ "UCSC genome browser". Retrieved 8 July 2014.
^ Kuhn, R. M.; Karolchik, D.; Zweig, A. S.; Wang, T.; Smith, K. E.;
Rosenbloom, K. R.; Rhead, B.; Raney, B. J.; Pohl, A.; Pheasant, M.;
Meyer, L.; Hsu, F.; Hinrichs, A. S.; Harte, R. A.; Giardine, B.;
Fujita, P.; Diekhans, M.; Dreszer, T.; Clawson, H.; Barber, G. P.;
Haussler, D.; Kent, W. J. (2009). "The
UCSC Genome Browser
UCSC Genome Browser Database:
Update 2009". Nucleic Acids Research. 37 (Database issue): D755–61.
doi:10.1093/nar/gkn875. PMC 2686463 . PMID 18996895.
^ A streamlined system for species diagnosis in Caenorhabditis
(Nematoda: Rhabditidae) with name designations for 15 distinct
biological species. MA Félix, C Braendle and AD Cutter, PLoS One,
^ Fire, A; Xu, S; Montgomery, MK; Kostas, SA; Driver, SE; Mello, CC
(1998). "Potent and specific genetic interference by double-stranded
Caenorhabditis elegans". Nature. 391 (6669): 806–11.
^ Harris, Todd W.; Antoshechkin, Igor; Bieri, Tamberlyn; Blasiar,
Darin; Chan, Juancarlos; Chen, Wen J.; de la Cruz, Norie; Davis, Paul;
Duesbury, Margaret; Fang, Ruihua; Fernandes, Jolene; Han, Michael;
Kishore, Ranjana; Lee, Raymond; Müller, Hans-Michael; Nakamura,
Cecilia; Ozersky, Philip; Petcherski, Andrei; Rangarajan, Arun;
Rogers, Anthony; Schindelman, Gary; Schwarz, Erich M.; Tuli, Mary Ann;
Van Auken, Kimberly; Wang, Daniel; Wang, Xiaodong; Williams, Gary;
Yook, Karen; Durbin, Richard; et al. (2010). "Worm Base: A
comprehensive resource for nematode research". Nucleic Acids Research.
38 (Database issue): D463–7. doi:10.1093/nar/gkp952.
PMC 2808986 . PMID 19910365.
Bird, J; Bird, AC (1991). The structure of nematodes. Academic Press.
pp. 1, 69–70, 152–153, 165, 224–225.
Hope, IA (1999). C. elegans: a practical approach. Oxford University
Press. pp. 1–6. ISBN 0-19-963738-5.
Riddle, DL; Blumenthal, T; Meyer, RJ; Priess, JR (1997). C. elegans
II. Cold Spring Harbor Laboratory Press. pp. 1–4, 679–683.
Wikimedia Commons has media related to:
Caenorhabditis elegans (category)
Wikispecies has information related to
Brenner S (2002) Nature's Gift to Science. In.
(also Horvitz and Sulston lectures)
WormBase – an extensive online database covering the biology and
genomics of C. elegans and other nematodes
WormAtlas – online database on all aspects of C. elegans anatomy
with detailed explanations and high-quality images
WormBook – online review of C. elegans biology
AceView WormGenes – another genome database for C. elegans,
maintained at the NCBI
C. elegans II – a free online textbook.
WormWeb Neural Network – an online tool for visualizing and
navigating the connectome of C. elegans
C. elegans movies – a visual introduction to C. elegans
View the ce11 genome assembly in the UCSC Genome Browser.
Caenorhabditis elegans at eppo.int (
EPPO code CAEOEL)
Major model organisms in genetics
Fauna Europaea: 224245