Phylogenetic relatedness rather than aquatic habitat fosters horizontal transfer of transposable elements in animals
Résumé
Horizontal transfer of transposable elements (HTT) is an important driver of genome evolution, yet the factors conditioning this phenomenon remain poorly characterized. Here, we screened 247 animal genomes from four phyla (annelids, arthropods, mollusks, chordates), spanning 19 independent transitions between aquatic and terrestrial lifestyles, to evaluate the suspected positive effects of aquatic habitat and of phylogenetic relatedness on HTT. Among the 5,952 independent HTT events recovered, the vast majority (>85%) involve DNA transposons, of which Mariner-like and hAT-like elements have the highest rates of horizontal transfer, and of intragenomic amplification. Using a novel approach that circumvents putative biases linked to phylogenetic inertia and taxon sampling, we found that HTT rates positively correlate with similarity in habitat type but were not significantly higher in aquatic than in terrestrial animals. However, modelling the number of HTT events as a function of divergence time in a Bayesian framework revealed a clear positive effect of phylogenetic relatedness on HTT rates in most of the animal species studied (162 out of 247). The effect is very pronounced: a typical species is expected to show 10 times more transfers with a species it diverged from 125 million years (My) ago than with a species it diverged from 375 My ago. Overall, our study underscores the pervasiveness of HTT throughout animals and the impact of evolutionary relatedness on its dynamics.
Origine | Fichiers produits par l'(les) auteur(s) |
---|