Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR 5558, Villeurbanne, France.
Laboratoire d'Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Université de Poitiers, CNRS, UMR 7267, Poitiers, France.
PLoS Genet. 2019 Feb 1;15(2):e1007965. doi: 10.1371/journal.pgen.1007965. eCollection 2019 Feb.
More than any other genome components, Transposable Elements (TEs) have the capacity to move across species barriers through Horizontal Transfer (HT), with substantial evolutionary consequences. Previous large-scale surveys, based on full-genomes comparisons, have revealed the transposition mode as an important predictor of HT rates variation across TE superfamilies. However, host biology could represent another major explanatory factor, one that needs to be investigated through extensive taxonomic sampling. Here we test this hypothesis using a field collection of 460 arthropod species from Tahiti and surrounding islands. Through targeted massive parallel sequencing, we uncover patterns of HT in three widely-distributed TE superfamilies with contrasted modes of transposition. In line with earlier findings, the DNA transposons under study (TC1-Mariner) were found to transfer horizontally at the highest frequency, closely followed by the LTR superfamily (Copia), in contrast with the non-LTR superfamily (Jockey), that mostly diversifies through vertical inheritance and persists longer within genomes. Strikingly, across all superfamilies, we observe a marked excess of HTs in Lepidoptera, an insect order that also commonly hosts baculoviruses, known for their ability to transport host TEs. These results turn the spotlight on baculoviruses as major potential vectors of TEs in arthropods, and further emphasize the importance of non-vertical TE inheritance in genome evolution.
与其他基因组元件相比，转座元件 (TEs) 具有通过水平转移 (HT) 跨越物种屏障的能力，这带来了重大的进化后果。以前基于全基因组比较的大规模调查表明，转座模式是 TE 超家族 HT 率变化的一个重要预测因子。然而，宿主生物学可能代表另一个主要的解释因素，需要通过广泛的分类学采样来研究。在这里，我们使用来自塔希提岛和周边岛屿的 460 种节肢动物的实地采集来检验这一假设。通过有针对性的大规模平行测序，我们揭示了三种广泛分布的 TE 超家族中 HT 的模式，这些超家族的转座模式截然不同。与早期的发现一致，所研究的 DNA 转座子 (TC1-Mariner) 被发现以最高的频率水平转移，紧随其后的是 LTR 超家族 (Copia)，而与非 LTR 超家族 (Jockey) 形成对比，后者主要通过垂直遗传多样化，并在基因组中持续存在更长时间。引人注目的是，在所有超家族中，我们观察到鳞翅目昆虫的 HT 明显过多，鳞翅目昆虫是一个昆虫目，通常也是杆状病毒的宿主，杆状病毒以其运输宿主 TE 的能力而闻名。这些结果将焦点放在杆状病毒作为节肢动物 TE 的主要潜在载体上，并进一步强调了非垂直 TE 遗传在基因组进化中的重要性。
