Transposable elements mobilization:  What does not kill you, makes you stronger

Leandro Quadrana Institut de Biologie de l’Ecole Normale Supérieure (IBENS). Paris – France Abstract Transposable elements (TEs) are ubiquitous parasitic DNA sequences that self-propagate throughout almost all genomes. Despite their great importance as generators of evolutionary novelty, the range and phenotypic consequences of heritable mutations produced upon their mobilization remain largely unknown. In this seminar I will present our efforts to characterize transposition activity and landscapes using genomics data from hundreds of A. thaliana natural inbred lines. Our results demonstrate that TE mobilization is a recurrent source of rare alleles with large effects. Moreover, using an experimental population of A. thaliana epigenetic recombinant inbred lines (epiRILs) we found that chromatin is a major determinant of the spectrum and phenotypic consequences of transposition. Last, I will present recent data indicating that polymorphic TE insertions constitute an untapped source of large phenotypic changes in crops, which cannot be accounted for by using classical single nucleotide polymorphisms data. Thus, TE mobilization is an important, yet largely underappreciated, source of heritable phenotypic variation with consequences for adaptation as well as crop improvement.