How does selfing affect the dynamics of selfish transposable elements?

Selfing has a deep impact on TE dynamics: the higher the selfing rate, the lower the probability of invasion. Already known non-equilibrium dynamics (complete loss, domestication, cyclical invasion of TEs) can all be described whatever the mating system. However, their pattern and their respective frequencies greatly depend on the selfing rate. For instance, in cyclical dynamics resulting from interactions between autonomous and non-autonomous copies, cycles are faster when the selfing rate increases. Interestingly, an abrupt change in the mating system from sexuality to complete asexuality leads to the loss of all the elements over a few hundred generations. In general, for intermediate selfing rates, the transposition activity remains maintained.Our theoretical results evidence that a clear and systematic contrast in TE content according to the mating system is expected, with a smooth transition for intermediate selfing rates. Several parameters impact the TE copy number, and all dynamics described in allogamous populations can be also observed in partly autogamous species. This study thus provides new insights to understand the complex signal from empirical comparison of closely related species with different mating systems.Transposable elements (TEs) are now considered as major components of genomes. These DNA sequences are able to invade, to multiply, and to spread across species despite their deleterious impact (on average) on their host. The capacity to generate structural and functional variability illustrates their impact on genome evolution [1-3]. If their ubiquity and their features can be only explained by selfishness [4,5], they are also able to enhance genome evolvability and to promote molecular exaptation. Their influence on genome evolution is supported by an increasing number of observations [6,7], including gene regulation via epigenetics landmarks [8-10], or the emergence of the V(D)J immune system in mammals [11].The complex co-evolutionary dyna