Submitted to the Department of Biology in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy

Proper development of cell types and tissues requires the integration of extracellular signals to provide context specific information that ensures appropriate differentiation. The Drosophila eye is an excellent model for the study of this signal integration, as its development is orchestrated by the interactions of common signal transduction pathways in conjunction with organ specific gene expression. Signaling through the NOTCH, DECAPENTAPLEGIC/ TRANSFORMING GROWTH FACTOR-P, WINGLESS, HEDGEHOG, and EPIDERMAL GROWTH FACTOR RECEPTOR pathways sets the stage for appropriate deployment of the Retinal Determination (RD) gene network members to direct formation of the eye and other