title: Large-scale DNA editing of retrotransposons accelerates mammalian genome evolution.
abstract: Retrotransposons had an important role in genome evolution, including the formation of new genes and promoters and the rewiring of gene networks. However, it is unclear how such a repertoire of functions emerged from a relatively limited number of source sequences. Here we show that DNA editing, an antiviral mechanism, accelerated the evolution of mammalian genomes by large-scale modification of their retrotransposon sequences. We find numerous pairs of retrotransposons containing long clusters of G-to-A mutations that cannot be attributed to random mutagenesis. These clusters, which we find across different mammalian genomes and retrotransposon families, are the hallmark of APOBEC3 activity, a potent antiretroviral protein family with cytidine deamination function. As DNA editing simultaneously generates a large number of mutations, each affected element begins its evolutionary trajectory from a unique starting point, thereby increasing the probability of developing a novel function. Our findings thus suggest a potential mechanism for retrotransposon domestication.
authors: The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
authors: Shai
authors: S
authors: Carmi
authors: George M
authors: GM
authors: Church
authors: Erez Y
authors: EY
authors: Levanon
mesh_terms: D000465:Algorithms; D000818:Animals; D004247:DNA / Q000235:genetics*; D019143:Evolution, Molecular; D016678:Genome / Q000235:genetics*; D006801:Humans; D008322:Mammals / Q000235:genetics*; D009154:Mutation; D018626:Retroelements / Q000235:genetics*
chemical_list: D018626:Retroelements; D004247:DNA