Although much attention has focused on the genetic control of development in the central nervous system of Drosophila, development of the neuromusular system is largely unexplored. The proposed research seeks to identify the precursor cells that differentiate during metamorphosis to form the thoracic muscles mediating the escape response. The large size of metamorphosing flies, relative to embryos, makes their developing muscles ideal for physiological testing, anatomical analyses, and surgical intervention. The investigators will follow during metamorphosis the differentiation of normal muscle precursors, determine which developmental steps are perturbed in mutant flies lacking escape- response muscles, and identify the function(s) controlled by the wild-type alleles of the mutant genes. To further characterize the action(s) of genetic mutations that prevent formation of muscles or cause them to degenerate prematurely, the investigators will test whether transplanted muscle precursors reverse mutant defects. Results from these experiments should help to determine whether defects in muscles or in neurons innervating muscles cause muscle deficiencies. This information should enable the investigators in future to identify the gene products that are required to complete the complex process of muscle formation.
