Since the discovery of the gene for green fluorescent protein (GFP), derived from jellyfish, this protein that emits a green glow has initiated a revolution in molecular biosciences. With this tool, it is now possible to visualize nearly any protein of interest in any cell or tissue of any species. Since the publication of the first edition, there have been tremendously significant technological advances, including development of new mutant variants. Proteins are now available in yellow and...