GENETIC AND ENVIRONMENTAL BASIS OF NATURAL TRANSPOSITION AND ITS POTENTIAL TO CREATE ADAPTIVE VARIATION

ongoing

Transposable elements (TEs) are powerful engines of genome evolution, as illustrated by their implication in the rewiring of regulatory networks and the creation of new cellular functions. Short-term consequences of TE mobilization can also be particularly dramatic given that TE insertions are a unique source of large effect mutations. However, there is a lack of knowledge about the contribution of ongoing transposition to within-species variation. This situation stems in large part from the repetitive nature of TEs, which complicates their analysis. Moreover, TE mobilization is typically rare and therefore new TE insertions tend to be missed in small-scale population studies. Hence, a major challenge in genomics is to determine the conditions leading to transposition in nature and the range of effects it generates. While most TE insertions are likely to be deleterious or neutral, it is widely proposed that because TE activity can be sensitive to the environment, transposition may in fact act as a major adaptive response of the genome to environmental changes. Here, using large experimental and wild populations of the plant A. thaliana, I propose to leverage innovative genomic, molecular genetics and eco-evolutionary approaches to determine the Genetic x Environmental (GxE) map of heritable transposition and its contribution to the creation of adaptive variation. Aim 1 is to identify the genetic and environmental factors that underpin TE mobilization by quantifying newly generated heritable insertions in thousands of genetically diverse individuals subjected to a range of environmental stressors. Aim 2 is to determine the fitness effects of these heritable TE insertions using multigenerational competition experiments and highly complex environments. This project will greatly increase our understanding of the nature of the genetic variation TEs contribute to and our ability to predict the impact of ongoing transposition, notably in the context of climate change.