CELL FATE DETERMINATION IN DROSOPHILA

A major issue in development is to understand how local heterogeneitie s are interpreted to determine specific cell fates. The sense organs o f Drosophila provide an accessible system for addressing this issue. M ost sense organs comprise four types of cells, and their differentiati on is the outcome of a complex developmental programme comprising seve ral steps. Recent results illuminate, for several of these steps, the nature of the local heterogeneities and the mechanism used to interpre t them in terms of cell fate decisions.