''Ciona'' is a genus of
sea squirts in the family
Cionidae.
The body of ''Ciona'' is bag-like and covered by a
tunic
A tunic is a garment for the body, usually simple in style, reaching from the shoulders to a length somewhere between the hips and the knees. The name derives from the Latin ''tunica'', the basic garment worn by both men and women in Ancient Rom ...
, which is a secretion of the
epidermal
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...
cells. The body is attached at a permanent base located at the posterior part, and the opposite bears two openings, the
buccal (
oral
The word oral may refer to:
Relating to the mouth
* Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid
**Oral administration of medicines
** Oral examination (also known as an oral exam or ora ...
) and
atrial
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
(
cloaca
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds ...
l)
siphon
A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...
s. The water is drawn into the
ascidian
Ascidiacea, commonly known as the ascidians, tunicates (in part), and sea squirts (in part), is a polyphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic ...
through the buccal siphon and leaves the
atrium through the atrial siphon.
Species
Species in this genus include:
* ''
Ciona antarctica
''Ciona'' is a genus of sea squirts in the family Cionidae.
The body of ''Ciona'' is bag-like and covered by a tunic, which is a secretion of the epidermal cells. The body is attached at a permanent base located at the posterior part, and the ...
''
* ''
Ciona edwardsi''
* ''
Ciona fascicularis''
* ''
Ciona gelatinosa
''Ciona'' is a genus of sea squirts in the family Cionidae.
The body of ''Ciona'' is bag-like and covered by a tunic, which is a secretion of the epidermal cells. The body is attached at a permanent base located at the posterior part, and the opp ...
''
* ''
Ciona hoshinoi''
* ''
Ciona imperfecta''
* ''
Ciona intermedia''
* ''
Ciona intestinalis
''Ciona intestinalis'' (sometimes known by the common name of vase tunicate) is an ascidian (sea squirt), a tunicate with very soft tunic. Its Latin name literally means "pillar of intestines", referring to the fact that its body is a soft, tran ...
''
* ''
Ciona longissima''
* ''
Ciona mollis''
* ''
Ciona pomponiae''
* ''
Ciona robusta''
* ''
Ciona roulei''
* ''
Ciona savignyi''
* ''
Ciona sheikoi''
Genome projects
As of 2008, the genomes of ''Ciona intestinalis''
[P. Dehal et al.: ''The draft genome of Ciona intestinalis: insights into chordate and vertebrate origins.'' Science, 298, 5601, S. 2157–67, 13. Dezember 2002] and ''Ciona savignyi''
[The C. savignyi Reference Genome and Genetic Map](_blank)
/ref> have been sequenced.
Sexual reproduction
'' C. intestinalis'' is a hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many taxonomic groups of animals (mostly invertebrates) do not have ...
that releases sperm and eggs almost simultaneously into the surrounding seawater. ''C. intestinalis'' is self-sterile and thus has been used for studies on the mechanism of self-incompatibility.inbreeding depression
Inbreeding depression is the reduced biological fitness which has the potential to result from inbreeding (the breeding of related individuals). Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. ...
,outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity.
Outcrossing can be a useful ...
which allows the masking of deleterious recessive mutations.
References
External links
The Tunicate Portal
an access point to the main websites and databases dealing with tunicates
Ascidians.com
pictures of species around the world
ANISEED
a model organism database for several ascidians species including ''Ciona intestinalis'' and ''Halocynthia roretzi''
JGI Ciona intestinalis v2.0
genome sequence
*
Enterogona
Tunicate genera
{{tunicata-stub