Green fluorescent proteins have been floating in the ocean for more than 160 million years, but it took a curious scientist, fascinated by pinpricks of green light, to begin unlocking their potential. Now these jellyfish proteins have become one of the most important tools available to researchers in modern medicine and biology. By using them to illuminate other proteins that were previously invisible even under a microscope, scientists are now able to observe facets of disease that would have otherwise gone undetected. Green fluorescent proteins are used in over three million experiments a...