Abstract
Mutations disrupting several different types of behavior in Drosophila are currently under intensive investigation (reviewed by Benzer, 1973; Grossfield, 1975; Pak, 1975; Pak and Pinto, 1976). The purpose is to unravel basic features of the development and function of the many parts of the nervous system, through studies of perturbations in nervous system embryology and physiology. To use the fly’s visual system merely as an example, one could attempt to analyze this system, through the isolation of mutations showing defects in visually triggered behavior (and many such mutants, to be discussed later, have been found). Given all the background information on the development and anatomy of the photoreceptor cells and neurons in the optic lobes (e.g., Meinertzhagen, 1973), one could ask if a behavior mutant involving the visual system has disrupted cell differentiation or the formation of nerve connections in the developing system. Since much is known about the physiology of vision in Drosophila (e.g., Pak, 1975), one could ask if this kind of mutant is defective in a process such as membrane permeability changes, caused by light-induced changes in photopigment conformation. The eventual aim is to learn how the action of particular genes programs into the animal such unknown mechanisms as those having to do with the formation of nerve connections and those involved in phototransduction.