Developmental Colloquium Seminar
Epigenetic and Symbiotic Responses to Unforeseen Toxicity - Mechanisms and Transgenerational Implications
Developing organisms have evolved a wide range of mechanisms for responding to ‘familiar’ (i.e. recurrent) environmental inputs. How they cope with rare or unforeseen types of stress is largely unknown and the evolutionary implications of such gene-environment interactions are unclear.
We investigate these questions using a synthetic drug/anti-drug system for confronting the development of the fly, D. melanogaster, with artificial distributions of toxic stress that are not expected to occur during fly development. Survival of the flies in this system depends of their ability to modify their development.
We found that this stress modifies the otherwise robust patterns of development, resulting in changes in gene expression as well as in the rate of larval development and adult morphology (in some of the cases). We show that part of this response is enabled by stress induced suppression of Polycomb group genes (PcG), which leads to de-repression of developmental regulators and their expression in new domains, hence the change in developmental patterns. Some of the induced developmental changes were non-genetically inherited by subsequent generations of non-exposed offspring suggesting that the stress also modifies the germline of the flies. In support of this hypothesis, we provide evidence indicating that the inheritance is maintained by a combined action of germline and microbial-mediated mechanisms of transgenerational transfer.
These results reveal a process of non-genetic response with trans-generational implications. It is enabled by environmental suppression of Polycomb and persists for multiple generations by epigenetic and symbiotic mechanisms.
Open to faculty and students of the university community