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 opposite bears two openings, the buccal (oral) and atrial (cloacal) siphons. The water is drawn into the ascidian through the buccal siphon and leaves the atrium through the atrial siphon.
As of 2008, the genomes of Ciona intestinalis[2] and Ciona savignyi[3] have been sequenced.
Sexual reproduction
Ciona intestinalis is a hermaphrodite 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.[4]C. savigny is highly self-fertile, but non-self sperm out-compete self-sperm in fertilization competition assays.[5] Mechanisms promoting non-self fertilization may have evolved to avoid inbreeding depression,[5] and to facilitate outcrossing which allows the masking of deleterious recessive mutations.[6]
Use as food
Ciona is being developed in Norway as a potential substitute meat protein, after processing to remove its 'marine taste' and to make its texture less 'squid-like'.[7]
^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
^Sawada H, Morita M, Iwano M (August 2014). "Self/non-self recognition mechanisms in sexual reproduction: new insight into the self-incompatibility system shared by flowering plants and hermaphroditic animals". Biochem. Biophys. Res. Commun. 450 (3): 1142–8. doi:10.1016/j.bbrc.2014.05.099. PMID24878524.
