The crystalline ommatidia of the fly eye may have more in common with the
aqueous orb of the vertebrate than ever expected. Earlier work has shown
that signals that initiate insect and vertebrate eye development share
similarities. Neumann and Nuesslein-Volhard (p. 2137) now show that the
pattern-forming wave that sweeps across the Drosophila retina also has a
correlate in the zebrafish eye, in that similar molecular signals are
involved. Neurogenesis in the vertebrate eye, however, seems to depend on a
group of related signals, rather than just the one signal found in the
Drosophila eye.