The dynamics of patterning in the Drosophila wing imaginal discs change under different environmental and internal cues. Marisa Oliveira¹, Alexander Shingleton², Christen Mirth¹. 1) Instituto Gulbenkian de Ciência, Oeiras, Oeiras, Portugal; 2) Dept. of Zoology, Michigan State University.

   Organisms require precisely coordinated developmental patterning programs to ensure the correct formation of structures and to produce a mature adult. To achieve this, the changes in gene expression that occur in tissues as they pattern need to be integrated with the systemic hormone levels that trigger developmental transitions. This integration must be robust across environmental conditions and between genetic backgrounds. This study addresses developmental coordination by examining how patterning dynamics in the wing imaginal disc of the fruit fly, Drosophila melanogaster, adjusts to environmental and systemic perturbations to ultimately produce functional adult tissues. We first described how developmental patterning programs progress over time. This was done by describing the development of the Drosophila third larval instar based on the gene expression pattern profile of the wing imaginal disc. These careful descriptions of the patterning events were used to compose a staging map for this period of development. We then used this map as a way to infer the intrinsic developmental clock of the tissue and organism. Secondly, we altered developmental timing, using temperature and genetic manipulations, to generate both fast and slow developing larvae. We then compared wing disc patterning between treatments. Surprisingly, not all gene expression profiles coordinate with developmental time in fast developing larvae. For slow developers, the developmental dynamics of patterning extend linearly with the developmental time. Finally, the beginning of wandering does not correlate with the patterning profiles, indicating that the hormonal cues regulating this developmental event do not coordinate patterning in the disc at this time. However, pupariation works as a checkpoint to which patterning profiles are aligned.