1. ¹UFSM—Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
2. ²UNESP—Universidade Estadual Paulista, São José do Rio Preto, SP, Brazil
3. ³CNRS Laboratoire Evolution, Génomes et Spéciation, CNRS, Gif/Yvette, France
4. ⁴Univ Paris-Sud, Orsay, France

Correspondence: Professor P Capy, CNRS Laboratoire Evolution, Génomes et Spéciation, CNRS, Gif/Yvette, France. E-mail: pierre.capy@legs.cnrs-gif.fr

Received 4 April 2007; Revised 10 December 2007; Accepted 11 December 2007; Published online 23 April 2008.

Abstract

Horizontal transfer (HT), defined as the transfer of genetic material between species, is considered to be an essential step in the 'life cycle' of transposable elements. We present a broad overview of suspected cases of HT of transposable elements in Drosophila. Hundred-one putative events of HT have been proposed in Drosophila for 21 different elements (5.0% refer to non-long terminal repeat (LTR) retrotransposons, 42.6% to LTR retrotransposons and 52.4% to DNA transposons). We discuss the methods used to infer HT, their limits and the putative vectors of transposable elements. We outline all the alternative hypotheses and ask how we can be almost certain that phylogenetic inconsistencies are due to HT.