Heritability of epigenetic marks in insects

Epigenetic marks are chemical modifications of DNA and histones that occur in all living organisms, mainly through methylation. We are interested in investigating the potential of stable epigenetic marks that might contribute to lasting and heritable phenotypes in insects. We hypothesize that this could constitute an adaptive mechanism when similar climatic features that have induced them will return. We report some experimental evidence for the molecular basis of insect adaptation to the fluctuating environment and for the gene regulatory process that underline phenotypic plasticity. Although significant advances have been obtained with plants, little is known about insects. The objective of our work was to use the aphid model to determine the components of epigenetic regulation due to the fact this species present a bimodal mode of reproduction: clonality in spring and summer, sexuality in autumn. Our aim is to determine whether epigenetic marks, in particular genome methylation, induced by an extreme climate phase might be heritable across clonality (spring and summer) and also whether this heritability might pass the sexual barrier (fall and winter) to be transmitted in the newly emerged clonal generations the next spring, in order to achieve adaptation. Although fascinating, this model has limited genetic tools to answer the questions. Thus, we aimed to couple aphid biology with Drosophila genetic tools in order to elucidate the underlying mechanisms at stake in insects. Ref: Continued Neurogenesis in Adult Drosophila as a Mechanism for Recruiting Environmental Cue-Dependent Variants. Selim Ben Rokia-Mille, Sylvette Tinette, Gilbert Engler, Laury Arthaud, Sophie Tares, Alain Robichon Plos One 2008 (6):e2395 Profiling the repertoire of phenotypes influenced by environmental cues that occur during asexual reproduction. Aviv Dombrovsky, Laury Arthaud, Terence N. Ledger, Sophie Tares and Alain Robichon. Genome Research 2009 Vol 11 2052-63 Trade-off between toxicity and signal detection orchestrated by frequency and density dependent genes Laury Arthaud, Selim Ben Rokia-Mille, Hussein Raad, Aviv Dombrovsky, Nicolas Prevost, Maria Capovilla and Alain Robichon Plos One 2011 6(5) e19805