In 1995, the eyeless (ey) gene was dubbed the "master-regulator" of eye 
development in Drosophila. Not only is ey required for eye development, but its 
misexpression can convert many other tissues into eye, including legs, wings and 
antennae.(1) ey is remarkable for its ability to drive coordinate 
differentiation of the multiple cell types that have to differentiate in a very 
precise pattern to construct the fly eye, and for its power to override the 
previous differentiation programs of many other diverse tissues. Even more 
remarkable, the ey homolog Pax6 and homologs of other eye determination genes 
from Drosophila are also required for eye development in vertebrates,(2,3) 
prompting reassessment of the evolution of vision throughout the animal 
kingdom.(4,5) Now Kumar and Moses have published a study that throws a new light 
on ey function in Drosophila.(6) According to their work, ey becomes a master 
regulator of eye development much later than previously thought, and is 
regulated by signalling through the Notch and EGFR signaling pathways.