by Elio | When was green florescent protein (GFP) first used with a prokaryote? Or with a eukaryote for that matter? It seems that the first paper on the subject was by Chalfie, Tu, Euskirchen, Ward, and Prasher, published in Science in 1994. For this work, Chalfie received the 2008 Nobel prize (with Shimomura and Tsien). The original purpose of this work seems to have been to determine if additional proteins are needed to form the light-absorbing component that imparts color to a molecule, known as the chromophore (spoiler: they aren’t; GFP does just fine by itself). How did they determine this?