This year’s Nobel Prize in Chemistry has been awarded to Osamu Shimomura, Martin Chalfie and Roger Tsien for the discovery and development of Green Fluorescent Protein as a research tool. GFP has revolutionized many aspects of biological research, allowing for real-time imaging of living specimens, rather than the difficult task of trying to piece together a process from a series of dead, fixed and stained specimens. Quoting from DNA Science:

“In the early 1960’s, Osamu Shimomura and Frank Johnson at Princeton University collected specimens of jellyfish in studies to understand their “bioluminescence.” One of the compounds they discovered was named green fluorescent protein (GFP) because it glowed bright green under UV light. Many years later, in 1992, Douglas Prasher at the Woods Hole Oceanographic Institute cloned a cDNA for GFP. In 1994, Prasher and Martin Chalfie at Columbia University were the first to realize the potential for use of GFP as a reporter molecule.”

Tsien comes into the story later, and has been instrumental in understanding how GFP works, and in extending the color palate beyond green into a wide variety of wavelengths, allowing for multi-spectral analysis of many labeled objects at the same time.

CSH Protocols has many articles detailing the use of GFP (with more continually on the way). You can see a list of available protocols here.