Developmental abnormalities in Drosophila induced by heat shock

We have for some years been making use of phenocopies in Drosophila, as induced by heat shock, as tools for studies of the molecular events in morphogenesis [18, 21, 22]. In this paper, we have brought together some accumulated information on the conditions for phenocopy production, on a temporal sequence of sensitivity to induction, and on the nature of many of the morphogenetic abnormalities that can be induced. In general, the induction of phenocopies by heat shock requires conditions drastic enough to turn off transcriptional activities but not extreme enough to prevent recovery. This situation is most easily achieved in pupal stages where heat resistance is high, but even in this range, resistance varies with the stage of development. The phenocopies described resemble, for the most part, mutants that affect structures derived from epithelial differentiation or muscle development.