A feature of this species is that it has a very small
genome, 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 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 pairs, 1,138 known and 18,093 novel
protein-coding genes, and 593
RNA genes. One type of torafugu, 22-seiki fugu (meaning "22nd-century fugu"), has been genetically modified by removing four
leptin receptor 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==