Removal of beneficial insertion effects prevent the long-term persistence of transposable elements within simulated asexual populations

Background: Transposable elements are significant components of most organism’s genomes, yet the reasons why their abundances vary significantly among species is poorly understood. A recent study has suggested that even in the absence of traditional molecular evolutionary explanations, transposon proliferation may occur through a process known as ‘transposon engineering’. However, their model used a fixed beneficial transposon insertion frequency of 20%, which we believe to be unrealistically high. Results: Reducing this beneficial insertion frequency, while keeping all other parameters identical, prevented transposon proliferation. Conclusions: We conclude that the author’s original findings are better explained through the action of positive selection rather than ‘transposon engineering’, with beneficial insertion effects remaining important during transposon proliferation events.