Retrotransposition of the Drosophila LINE I element can induce deletion in the target DNA: a simple model also accounting for the variability of the normally observed target site duplications.

Retrotransposition of the Drosophila melanogaster LINE I element normally generates target site duplications of variable length, as classically observed for most LINE elements. Using an I element "marked" with an indicator gene for in vivo detection of transposition that we previously developed, we show that deletion in the target DNA can also take place, as a direct consequence of I element transposition. We propose a simple model accounting for the generation of both target site duplications of variable length and target DNA deletions, which relies upon template switching of the LINE-encoded reverse transcriptase between single-strand DNA at the target site and the LINE template.