Transforming the architecture of compound eyes.

It's not often that you can glimpse the 'blind watchmaker' at work, says Kevin Moses in News and Views. The work he's referring to is the transition from the compound eyes found in ancestral flies and in some modern-day insects such as bees and beetles, where the light-sensing cells or rhabdomeres are fused together and function as a unit, to the type found in fruitfly and housefly eyes, where rhabdomeres act independently so that each facet of the lens perceives seven points of light instead of one. Zelhof et al. have identified three genes involved in rhabdomere assembly. The loss of one gene, called spacemaker, converts Drosophila's open system to a closed or fused-rhabdomere system.