The R8 Race: Patterning neurogenesis during Drosophila development

From Q-bio

We present a quantitative model of the formation of the R8 photoreceptor lattice in Drosophila development. In our model, R8 induction proceeds through the flipping of cell-autonomous switches, with existing R8's providing a template for the placement of new photoreceptors. This novel patterning mechanism has the dramatic consequence that, depending on initial conditions, both the normal triangular lattice and stripes of R8 cells can appear in genetically identical tissue. These predictions are confirmed experimentally by manipulation of the Notch and scabrous genes. Our model suggests an alternative to the textbook version of neural fate specification through lateral inhibition.