''Takifugu rubripes'', commonly known as the Japanese puffer, Tiger puffer, or torafugu ( ja, 虎河豚), is a

pufferfish Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowies, bubblefish, globefish, swellfis ...

in the genus ''

Takifugu ''Takifugu'' is a genus of pufferfish, often better known by the Japanese name . There are 25 species belonging to the genus ''Takifugu'' and most of these are native to salt and brackish waters of the northwest Pacific, but a few species are ...

''. It is distinguished by a very small

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

that has been fully sequenced because of its use as a model species and is in widespread use as a reference in genomics.

Taxonomy and etymology

The species is often referred to in the genomics literature as ''Fugu rubripes''. The genus ''Fugu'' is a synonym of the currently preferred ''

''. ''Takifugu'' is Japanese for puffer and ''rubripes'' comes from the Latin ''ruber'' and ''pēs'' meaning ruddy foot.

Distribution and habitat

The species is known from the

Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it h ...

East China Sea The East China Sea is an arm of the Western Pacific Ocean, located directly offshore from East China. It covers an area of roughly . The sea’s northern extension between mainland China and the Korean Peninsula is the Yellow Sea, separated b ...

and

Yellow Sea The Yellow Sea is a marginal sea of the Western Pacific Ocean located between mainland China and the Korean Peninsula, and can be considered the northwestern part of the East China Sea. It is one of four seas named after common colour terms ...

north to southern

Sakhalin Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh: ...

, at depths of . It is a

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

species. Spawning occurs in

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

; young fish can tolerate a wide range of salinities and will remain in river mouths and lagoons, maturing for one year before migrating permanently to the open ocean.

Genome

A feature of this species is that it has a very small

, which is used as a ‘reference’ for identifying genes and other elements in human and other vertebrate genomes. The genome was published in 2002 by the International Fugu Genome Consortium via whole genome shotgun sequencing. After being initiated in 1989, it was the first vertebrate genome after the

human genome The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. These are usually treated separately as the n ...

to be made publicly available. It remains among the smallest known vertebrate genomes; its number of base pairs is ~6% and the number of previously known protein-coding genes ~13% that of the human genome, although the number of chromosomes (22) is comparable to that of humans (23). This makes it particularly useful for comparative studies. Current estimates show a total of 392,376,244

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

s, 1,138 known and 18,093 novel protein-coding genes, and 593

RNA gene A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non- ...

s. One type of torafugu, 22-seiki fugu (meaning "22nd-century fugu"), has been genetically modified by removing four

leptin receptor Leptin receptor, also known as LEP-R or OB-R, is a type I cytokine receptor, a protein that in humans is encoded by the ''LEPR'' gene. LEP-R functions as a receptor for the fat cell-specific hormone leptin. LEP-R has also been designated as CD2 ...

genes that control appetite. The result has increased appetite and weight gain, growing on average 1.9 times faster than normal torafugu. It is sold commercially as food.

Toxicity

As some other pufferfish, some organs of the Japanese puffer contain

tetrodotoxin Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered ...

and are highly toxic. The toxin is highly concentrated in liver and ovaries, slightly present in the intestines and flesh, and absent from skin and testes.

Conservation

The Japanese puffer is classified as

Near Threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

. It is one of the most valuable commercial fishes in Japan, and although current catches (101 tonnes / year in 2004, down from a peak of 2,000 tonnes in 1987) are small compared to those of many other commercial species such as

sardine "Sardine" and "pilchard" are common names for various species of small, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century, a folk etymology says it comes from the Ital ...

s and

anchovy An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...

, they appear to be unsustainable and prevent the recovery of the species from earlier over-exploitation. Gear restrictions (most catches occur by

longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...

References

External links

Fugu Genome Project

* View th
fugu genome
on

Ensembl Ensembl genome database project is a scientific project at the European Bioinformatics Institute, which provides a centralized resource for geneticists, molecular biologists and other researchers studying the genomes of our own species and other v ...

{{Taxonbar, from=Q1065355 rubripes Fish described in 1850 Animal models Genomics