Universidade Estadual Paulista (Unesp), Instituto de Biociências Letras e Ciências Exatas (Ibilce), Câmpus São José do Rio Preto, SP, Brazil.
Univ Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France.
Genome Biol Evol. 2018 Oct 1;10(10):2671-2685. doi: 10.1093/gbe/evy184.
The frequency of horizontal transfers of transposable elements (HTTs) varies among the types of elements according to the transposition mode and the geographical and temporal overlap of the species involved in the transfer. The drosophilid species of the genus Zaprionus and those of the melanogaster, obscura, repleta, and virilis groups of the genus Drosophila investigated in this study shared space and time at some point in their evolutionary history. This is particularly true of the subgenus Zaprionus and the melanogaster subgroup, which overlapped both geographically and temporally in Tropical Africa during their period of origin and diversification. Here, we tested the hypothesis that this overlap may have facilitated the transfer of retrotransposons without long terminal repeats (non-LTRs) between these species. We estimated the HTT frequency of the non-LTRs BS and Helena at the genome-wide scale by using a phylogenetic framework and a vertical and horizontal inheritance consistence analysis (VHICA). An excessively low synonymous divergence among distantly related species and incongruities between the transposable element and species phylogenies allowed us to propose at least four relatively recent HTT events of Helena and BS involving ancestors of the subgroup melanogaster and ancestors of the subgenus Zaprionus during their concomitant diversification in Tropical Africa, along with older possible events between species of the subgenera Drosophila and Sophophora. This study provides the first evidence for HTT of non-LTRs retrotransposons between Drosophila and Zaprionus, including an in-depth reconstruction of the time frame and geography of these events.
转座元件（HTT）的水平转移频率因转座模式和参与转移的物种的地理和时间重叠而在不同类型的元件之间有所不同。本研究中调查的果蝇属 Zaprionus 种和果蝇属 melanogaster、obscura、repleta 和 virilis 组的种在其进化历史的某个时刻共享空间和时间。特别是在起源和多样化时期，Zaprionus 亚属和 melanogaster 亚组在热带非洲在地理和时间上重叠。在这里，我们测试了这样一种假设，即这种重叠可能促进了这些物种之间没有长末端重复（非 LTR）的逆转座子的转移。我们通过使用系统发育框架和垂直和水平遗传一致性分析（VHICA），在全基因组范围内估计了非 LTRs BS 和 Helena 的 HTT 频率。远缘物种之间过高的同义分歧以及转座元件和物种系统发育之间的不一致性，使我们能够提出至少四个涉及 melanogaster 亚组的祖先和 Zaprionus 亚属的祖先在热带非洲同时多样化的 Helena 和 BS 的相对较新的 HTT 事件，以及在 Drosophila 和 Sophophora 亚属的物种之间可能更早的事件。这项研究首次提供了果蝇属和 Zaprionus 属之间非 LTR 逆转座子 HTT 的证据，包括对这些事件的时间范围和地理范围的深入重建。
