 A dye such as green fluorescent protein, originally from a jellyfish, was typically attached to an antibody specific to a fruit fly protein, forming a precise indicator of where and when that protein appeared in the living embryo.Using such a technique, in 1994 Walter Gehring found that the "pax-6" gene, vital for forming the eyes of fruit flies, exactly matches an eye-forming gene in mice and humans.The same gene was quickly found in many other groups of animals, such as squid, a cephalopod mollusc.