Thanawala SU, Rister J, Goldberg GW, Zuskov A, Olesnicky EC, Flowers JM, Jukam D, Purugganan MD, Gavis ER, Desplan C, Johnston RJ Jr.

Dev Cell. 2013 Apr 15;25(1):93-105. doi:10.1016/j.devcel.2013.02.016

Regional modulation of a stochastically expressed factor determines photoreceptor subtypes in the Drosophila retina.

On/off expression of Spineless, but levels matter (lower levels allow IroC to interfere.)