We are interested in how genomes evolve and in the forces that shape them. In particular, we are curious about how selfish genetic elements, such as transposable elements (TEs), impact genomes. We study the dynamics of transposable elements in natural populations, experimental populations and through computer simulations. Recently, we have also become interested in the extent of horizontal transfer across species. We found that 12 different TEs were horizontally transferred in the fruit flies in the last 200 years. This finding raises many questions that we plan to pursue in future works, for example the consequences of these invasions and whether other species show similarly high rates of recent TE invasions.