Abstract
One of the striking findings in developmental genetics over the past two decades is the realization that a very small number of conserved signalling pathways directs most, if not all, aspects of development of multicellular organisms, by transmitting extracellular signals to the cell nucleus, to modify gene expression programs. How can such a small number of distinct pathways regulate an amazingly diverse array of developmental switches? The secret seems to lie in the capacity of the pathways to interact with each other and generate a varied array of outputs. Exemplifying this is a study by Nagaraj and Banerjee in this issue of The EMBO Journal, describing a novel function of the EGFR signalling target Phyllopod in the regulation of Notch and Wingless signalling in the Drosophila eye.
