Horizontal transfer and evolution of transposable elements in vertebrates

• Published in: Nature communications 2020-03, Vol.11 (1), p.1362-1362, Article 1362
• Main Authors: Zhang, Hua-Hao, Peccoud, Jean, Xu, Min-Rui-Xuan, Zhang, Xiao-Gu, Gilbert, Clément
• Format: Article
• Language: English
• Subjects: 631/1647/48; 631/181/2474; 631/181/735; 631/208/726; Animals; Biodiversity; Biological evolution; Birds; Computational Biology; Deoxyribonucleic acid; DNA; DNA Transposable Elements; Eukaryota - genetics; Evolution; Evolution, Molecular; Gene Transfer, Horizontal; Genome; Genomes; Horizontal transfer; Humanities and Social Sciences; Life Sciences; Mammals - genetics; multidisciplinary; Mutation Rate; Populations and Evolution; Proteins; Retroelements; Ribonucleic acid; RNA; Science; Science (multidisciplinary); Transposition; Transposons; Vertebrates; Vertebrates - genetics
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-15149-4

Horizontal transfer of transposable elements (HTT) is an important process shaping eukaryote genomes, yet very few studies have quantified this phenomenon on a large scale or have evaluated the selective constraints acting on transposable elements (TEs) during vertical and horizontal transmission. Here we screen 307 vertebrate genomes and infer a minimum of 975 independent HTT events between lineages that diverged more than 120 million years ago. HTT distribution greatly differs from null expectations, with 93.7% of these transfers involving ray-finned fishes and less than 3% involving mammals and birds. HTT incurs purifying selection (conserved protein evolution) on all TEs, confirming that producing functional transposition proteins is required for a TE to invade new genomes. In the absence of HTT, DNA transposons appear to evolve neutrally within genomes, unlike most retrotransposons, which evolve under purifying selection. This selection regime indicates that proteins of most retrotransposon families tend to process their own encoding RNA ( cis -preference), which helps retrotransposons to persist within host lineages over long time periods. Horizontal transfer (HT) and evolution of transposable elements (TEs) has rarely been quantified on a large scale. Here, the authors screen 307 vertebrate genomes and infer 975 HT events (93% in ray-finned fishes); all TEs involved in HT evolve within genomes under purifying selection, as do most retrotransposons.