Green fluorescent protein is a fundamental tool in biological research now. They stuck it not only in fish (available to the public now) but into mice too. Should be easier to catch at night
Yeah, it's been awhile for quite some time, but definitely worthy of a nobel prize...it's even an art form now, check out http://www.ekac.org/transgenic.html it's called transgenic art. GFP can be pretty much transferred into everything now, hence, I suppose, how the 'art' came about.
GFP tagging is a very cool technique, and really revolutionized sub-cellular localization studies. My thesis at MIT was done on the localization of DNA replication and cell division machinery in bacterial cells. I'd label a few different proteins with different colors of GFP, and then light the cells up like a christmas tree. Really eye opening to be able to see the previously invisible order inside those bacterial cells.
Since I run a flow cytometer, I work with GFP and related fluorphores on a daily basis. In fact, I just looked at some GFP positive cells about 45 minutes ago The discovery of that protein was HUGE, and the knowledge that has stemmed from it is just astounding.