lpetrich

That fish is the fugu pufferfish (Fugu (Takifugu) rubripes), best known for producing a dangerous toxin in its skin, guts, and gonads. Thus making eating Fugu a form of Russian Roulette. Pufferfish get their name from their habit of swallowing water when threatened; this makes them seem bigger and thus less convenient to eat.

But the real interest in the pufferfish genome is that it is relatively small by vertebrate standards (400 megabases, vs. human 3000), thus meaning that its genome has much less genetic junk in it. Here are <a href="http://www.jgi.doe.gov/News/news.htm#072602" target="_blank">some articles on that subject</a>.

Though the pufferfish genome is not quite completely assembled, enough of it is in hand to enable cross-comparisons. About 75% of it can be mapped onto the human genome, and 961 putative human genes have been discovered with the help of pufferfish comparisons.

Also, several clusterings of genes are highly conserved ("synteny") between the human and pufferfish genomes, though genes with greater separations are often scrambled relative to each other in different genomes. This has also been found for the parts of the zebrafish (Danio rerio) genome that have been sequenced; work is underway on sequencing its genome also.

Which suggests that there is a lot more to come as work with comparative genomics continues; one interesting question is what chromosome rearrangement events had led to present-day arrangements of genes in chromosomes. These events can provide additional information on phylogenies (family trees); it will be interesting to see how these compare with results from other methods.