Résumé
How genomes diverge and trigger the onset of organismal diversity remains a central question in biosciences. Comparative functional genomics have already provided many exciting insights on how genetic novelty and co-option, structural and gene regulatory innovation can lead to phenotypic diversification. Some of the most puzzling genomic innovations are triggered by Transposable Elements (TEs). Most host organisms adapted different mechanisms to temper the deleterious effects of TEs, silencing them through a variety of pathways, such as piwi-interacting RNAs (piRNAs) . Nevertheless, TEs still manage to recurrently colonize genomes over evolutionary time. While most TEs reach fixation within genomes through genetic drift, TEs can also promote the ability of populations to adapt to rapidly changing environments. Indeed, TE insertion can significantly alter phenotypes contrary to point mutations. While we start understanding the varying impact of TEs on genome evolution linked with phenotypic innovations, how and which TEs can promote phenotypic diversification need to be clarified. This can be only achieved if, and only if, the evolution of TEs, their host silencing pathways, and their interactions are investigated altogether. Blattodea insect order represents a great model system to investigate the role of TEs in the emergence of novel phenotypes, with their transposon-inflated genomes and biodiversity. Here, I described further evidence of the role of TEs during the eusocial transition through enhancing potential of gene regulation. In addition, TEs seems to be involved in the transition to viviparity in the only truly viviparous cockroach, Diploptera punctata. Furthermore, I will open perspectives to investigate the role of TEs and the host TE-silencing pathways in the emergence of novel phenotypes taking advantage of the great biodiversity of Blattodea.