Reconstructing the invasion route of DNA transposons using extant population samples

Abstract

Reconstructing invasion routes of transposable elements (TEs), so far, required capturing an ongoing invasion with population samples from different geographic regions and time points. Here, we propose a more accessible approach. Abundantly occurring internal deletions of DNA transposons allow to trace the direction as well as the path of an invasion, even hundreds of generations after the spread of a TE. We validated this hypothesis with computer simulations and by accurately reproducing the route of the P-element invasion in Drosophila melanogaster. Finally, we used our method to shed light on the controversial hobo invasion in D. melanogaster. Our approach solely requires sequenced samples from extant populations and sequences of TEs of interest. Hence, DNA transposons in a wide range of model and non-model organisms may be analyzed. Our approach will further our understanding of TE dynamics, migration patterns, and the ecology of species.