Ciona intestinalis
Encyclopedia
Ciona intestinalis is a urochordata (sea squirt), a tunicate
widely distributed in Northern Europe
an waters. As an invasive species
, it has also spread to other parts of the world.
Since Darwin's time, sea squirts have been recognized as being possibly the closest invertebrate
relative of humans. Its full genome
has been sequenced, one that shares 80% of its genes with humans. During the 21st century it has become a major experimental model
for developmental biologists.
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 and atrial siphons. The water is drawn into the ascidian through the buccal (oral) siphon and leaves the atrium through the atrial siphon (cloacal).
In their immature tadpole form, they resemble vertebrates.
Ciona intestinalis is considered to be an invasive species
and grows in dense aggregations on any floating or submerged substrate, particularly artificial structures like pilings, aquaculture gear, floats and boat hulls, in the lower intertidal to sub-tidal zones. Often grows with or on other fouling organisms.
It is thought to be spread to new areas mainly through hull fouling. Since its larvae can live for up to 10 days this species may also be transferred through the release of bilge or ballast water.
To avoid spreading this organism fish and shellfish harvesters should avoid transferring harvested shellfish and fishing gear to other areas. Gear should be thoroughly dried before transfer. Boat hulls should be inspected and, if necessary, thoroughly cleaned and disinfected with bleach or vinegar and dried before moving to other areas. Any organisms removed from boat hulls or gear should be disposed of on land. Bilge water should be released on land or disinfected.
has been sequenced
. It has a relatively small genome (about 160 Mbp
) consisting of 14 pairs of chromosome
s with about 16,000 genes.
The draft genome analysis identified nine Hox genes, which are Ci-Hox1, 2, 3, 4, 5, 6, 10, 12, and 13. Ciona savignyi, the closest relative of Ciona intestinalis, also have the same set of Hox genes. The organization of Hox genes is only known for C. intestinalis among ascidians. The nine Hox genes are located on two chromosomes; Ci-Hox1 to 10 on one chromosome and Ci-Hox12 and 13 on another. The intergenic distances within the Ciona Hox genes are extraordinarily long. Seven Hox genes, Ci-Hox1 to 10, are distributed, spanning approximately half the length of the chromosome. From comparisons to the Hox gene expressions and locations in other species, it is likely that the ascidian genomes are under a dispersing condition.
Tunicate
Tunicates, also known as urochordates, are members of the subphylum Tunicata, previously known as Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor, others such...
widely distributed in Northern Europe
Northern Europe
Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...
an waters. As an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
, it has also spread to other parts of the world.
Since Darwin's time, sea squirts have been recognized as being possibly the closest invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
relative of humans. Its full genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
has been sequenced, one that shares 80% of its genes with humans. During the 21st century it has become a major experimental model
Model organism
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...
for developmental biologists.
Appearance
Ciona intestinalis is a solitary tunicate with a cylindrical, gelatinous body, up to 14 cm long. The soft, smooth, translucent tunic (outer skin) is pale yellow or green in colour with orange body parts visible through the translucent tunic. Incurrent and excurrent siphons are easily seen near the tip of the organism.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 and atrial siphons. The water is drawn into the ascidian through the buccal (oral) siphon and leaves the atrium through the atrial siphon (cloacal).
In their immature tadpole form, they resemble vertebrates.
Ecology
Ciona intestinalis is a hermaphroditic broadcast spawner but cannot self-fertilize. Eggs and sperm, when released, can stay in the water column for 1 to 2 days while the larvae are free-swimming for 2 to 10 days.Ciona intestinalis is considered to be an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
and grows in dense aggregations on any floating or submerged substrate, particularly artificial structures like pilings, aquaculture gear, floats and boat hulls, in the lower intertidal to sub-tidal zones. Often grows with or on other fouling organisms.
It is thought to be spread to new areas mainly through hull fouling. Since its larvae can live for up to 10 days this species may also be transferred through the release of bilge or ballast water.
To avoid spreading this organism fish and shellfish harvesters should avoid transferring harvested shellfish and fishing gear to other areas. Gear should be thoroughly dried before transfer. Boat hulls should be inspected and, if necessary, thoroughly cleaned and disinfected with bleach or vinegar and dried before moving to other areas. Any organisms removed from boat hulls or gear should be disposed of on land. Bilge water should be released on land or disinfected.
Genetics
C. intestinalis is one of the animals whose full genomeGenome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
has been sequenced
Full genome sequencing
Full genome sequencing , also known as whole genome sequencing , complete genome sequencing, or entire genome sequencing, is a laboratory process that determines the complete DNA sequence of an organism's genome at a single time...
. It has a relatively small genome (about 160 Mbp
MBP
MBP may refer to:In biology:* Major basic protein, a protein which in humans is encoded by the PRG2 gene* Maltose-binding protein, a part of the maltose/maltodextrin system of Escherichia coli* Mbp, an abbreviation for mega base pairs...
) consisting of 14 pairs of chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s with about 16,000 genes.
The draft genome analysis identified nine Hox genes, which are Ci-Hox1, 2, 3, 4, 5, 6, 10, 12, and 13. Ciona savignyi, the closest relative of Ciona intestinalis, also have the same set of Hox genes. The organization of Hox genes is only known for C. intestinalis among ascidians. The nine Hox genes are located on two chromosomes; Ci-Hox1 to 10 on one chromosome and Ci-Hox12 and 13 on another. The intergenic distances within the Ciona Hox genes are extraordinarily long. Seven Hox genes, Ci-Hox1 to 10, are distributed, spanning approximately half the length of the chromosome. From comparisons to the Hox gene expressions and locations in other species, it is likely that the ascidian genomes are under a dispersing condition.
External links
- MarLIN, detailed species review
- Ciona intestinalis genome sequencing project the Joint Genome InstituteJoint Genome InstituteThe U.S. Department of Energy Joint Genome Institute was created in 1997 to unite the expertise and resources in genome mapping, DNA sequencing, technology development, and information sciences pioneered at the DOE genome centers at Lawrence Berkeley National Laboratory , Lawrence Livermore...
- ANISEED, a model organism database for Ciona intestinalis and Halocynthia roretzi
- Ghost: genomic and cDNA resources from Kyoto UniversityKyoto University, or is a national university located in Kyoto, Japan. It is the second oldest Japanese university, and formerly one of Japan's Imperial Universities.- History :...
- Four-dimensional Ascidian Body Atlas from Keio UniversityKeio University,abbreviated as Keio or Keidai , is a Japanese university located in Minato, Tokyo. It is known as the oldest institute of higher education in Japan. Founder Fukuzawa Yukichi originally established it as a school for Western studies in 1858 in Edo . It has eleven campuses in Tokyo and Kanagawa...
- Ciona intestinalis protein databaseCiona intestinalis protein databaseThe Ciona intestinalis protein database is a protein database for the tunicate species C. intestinalis....
: http://cipro.ibio.jp/ CIPRO from ibio.jp - intestinalis photos from ascidians.com