Shimomura collected and studied samples of liquid from these organs and found it contained a protein that glows green under ultraviolet light. This protein, initially dubbed aequorin, is what would later be called GFP.
In 1992 Columbia's Chalfie cloned GFP and used it to make the bacterium Escherichia coli glow fluorescent green.
Later the following year Chalfie repeated the technique in the transparent roundworm Caenorhabditis elegans, coloring six different cells in the worm's body with the glowing substance.
Alison Woollard, a scientist at the University of Oxford, said, "Using GFP on C. elegans, I have been able to study cells as they develop, working out how they know when to take on a particular role, such as becoming a skin cell or an intestinal cell."
GFP can also demonstrate how things go wrong in living cells.
In recent years the protein has played a crucial role in cancer research, helping scientists understand the ways that tumors form and grow. It has also been used to look at nerve cell damage caused by Alzheimer's disease.
UC-San Diego's Tsien later added a range of color options to researchers' palettes as part of his lab's work to understand the chemistry of GFP's fluorescence.
His team modified GFP and other bioluminescent proteins to produce new variants with fruity names such as mPlum, mCherry, mOrange, and mHoneydew.
Oxford's Woollard said, "The use of many colors enables us to look at many proteins simultaneously."
For example, recently researchers used a rainbow of fluorescent proteins to label different nerve cells in the brain of a mouse.
Sweeney, of the University of York, added: "When I worked in a lab in San Francisco, we called Dr. Tsien 'Dr. Genius.'
"We would await his publications eagerly for the next 'trick' or tool that was going to revolutionize the way we tackled problems."
Last year's chemistry Nobel went to German researcher Gerhard Ertl for his work on the chemistry of solid surfaces, which set the stage for advances such as hydrogen fuel cells and automobile catalytic converters.
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