Horizontal transfer in Drosophila has been inferred for several families of transposable elements. Specifically, the retroelement roo has been suggested to have been horizontally transferred between the species D. melanogaster, D. simulans, D. sechellia and D. yakuba. The inferences were based on the observation that divergence between transposable elements in different species was lower than the divergence found in typical nuclear genes and in the incongruence of phylogenies of the species and their TEs. Here, we address the question of the possible horizontal transfer of roo between species of the Drosophila genus by studying the presence absence of a duplication of 99 bp in the 5’UTR of the transposon, as well as comparing the sequences of the paralogous and orthologous duplicated repeats within and between species. First, the repeats were only found in five species of the melanogaster subgroup. Second, the date of occurrence of the duplication event originating the repeats was posterior to the split of the subgroup. The duplication date suggests an origin previous to the split of D. simulans and D. sechellia and close to the divergence of D. melanogaster from the D. simulans complex. These data point to horizontal transfer to the afrotropical species D. yakuba and D. erecta from one of the cosmopolitan species D. melanogaster or D. simulans. We propose that the parasitoid wasp Leptopilina could have been the vector of horizontal transfer after the observation that a sequence of 845 bp with high homology to a fragment of roo was isolated from this wasp.

已经推断出几个可转座元件家族在果蝇中的水平转移。具体而言，retroelement roo已被建议已在物种D. melanogaster、D. simulans、D. sechellia和D. yakuba之间水平转移。这些推论是基于观察到不同物种中转座因子之间的差异低于典型核基因中发现的差异以及物种及其 TE 系统发育的不一致。在这里，我们解决了果蝇物种之间roo可能水平转移的问题通过研究转座子 5'UTR 中是否存在 99 bp 重复，以及比较物种内部和物种之间的旁系同源和直系同源重复重复序列的序列，来确定该属。首先，重复仅在黑腹亚群的五个物种中发现。其次，引起重复的重复事件的发生日期在亚组分裂之后。重复日期表明起源于D. simulans和D. sechellia的分裂之前，并且接近D. melanogaster与D. simulans复合体的分歧。这些数据表明向非洲热带物种D. yakuba和D.万寿菊从世界性的物种之一果蝇或D.，模仿。我们建议寄生蜂Leptopilina在观察到从该黄蜂中分离出与roo片段具有高度同源性的 845 bp 序列后可能是水平转移的载体。