Retransposition of the Drosophilia 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.