Thesis defense Anaïs Larue

Jury members :

Cameron GHALAMBOR Rapporteur

Professeur, Norwegian University of Science and Technology (NTNU)

Christoph GRUNAU Rapporteur

Professeur, Université de Perpignan Via Domitia

Pascale LESAGE Rapportrice

Directrice de Recherche, Institut national de la santé et de la recherche médicale (INSERM)

 Patricia GIBERT Examinatrice

Directrice de Recherche, Centre National de la recherche scientifique (CNRS)

Abdelaziz HEDDI Examinateur

Professeur, Institut National des Sciences Appliquées (INSA)

François SABOT Examinateur

Directeur de Recherche, Institut de Recherche pour le Développement (IRD)

Rita REBOLLO Directrice de thèse

Chercheuse, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE)

Cristina VIEIRA Co-encadrante de thèse

Professeure, Université Claude Bernard Lyon 1 (UCBL1)

Séverine CHAMBEYRON Invitée

Directrice de Recherche, Centre national de la recherche scientifique (CNRS)

 Abstract :

Phenotypic plasticity refers to the ability of an organism with a given genotype to produce a range of phenotypes in response to environmental changes. In an adaptive context, this plasticity can enhance an organism's ability to face environmental fluctuations. Transposable elements (TEs) are ubiquitous repetitive DNA sequences that are capable of moving within genomes. Although often overlooked in the context of phenotypic plasticity, may play a significant role through their ability to modulate gene expression in an environmentally-dependent manner. The epigenetic control machinery that regulates TEs, as well as their intrinsic regulatory components, can be tuned to the environmental fluctuations. These fluctuations may lead to differential TE expression or mobilization, potentially influencing gene expression and inducing epigenomic, genomic, and transcriptomic plasticity. Such plasticity at the molecular level could ultimately lead to inter-individual diversity and phenotypic plasticity. In order to investigate this hypothesis in controlled conditions, we used genetically engineered Drosophila melanogaster flies that have different TE content but share a common genetic background. Phenotypic screening revealed significant differences between populations. Further investigation of the plastic response under different environment conditions revealed variations in plastic responses and an increase in trait variance for the TE-burdened populations. These findings suggest that TEs contribute to the heterogeneity in environmental response and therefore can be an additional underlying mechanism to phenotypic plasticity.