An oldie but goodie: Meet Alba, a transgenic bunny that fluoresced green (when exposed to uv light ... okay, not exactly glow in the dark - but close enough) thanks to a jellyfish gene for Green Fluorescent Protein (GFP). Alba was genetically engineered by Eduardo Kac in 2000:
"Alba", the green fluorescent bunny, is an albino rabbit. This means that, since she has no skin pigment, under ordinary environmental conditions she is completely white with pink eyes. Alba is not green all the time. She only glows when illuminated with the correct light. When (and only when) illuminated with blue light (maximum excitation at 488 nm), she glows with a bright green light (maximum emission at 509 nm). She was created with EGFP, an enhanced version (i.e., a synthetic mutation) of the original wild-type green fluorescent gene found in the jellyfish Aequorea Victoria. EGFP gives about two orders of magnitude greater fluorescence in mammalian cells (including human cells) than the original jellyfish gene [2].