Data from: Non-allelic gene conversion enables rapid evolutionary change at multiple regulatory sites encoded by transposable elements

Transposable elements (TEs) allow rewiring of regulatory networks, and the recent amplification of the ISX element dispersed 77 functional but suboptimal binding sites for the dosage compensation complex to a newly formed X chromosome in Drosophila. Here we identify two linked refining mutations within ISX that interact epistatically to increase binding affinity to the dosage compensation complex. Selection has increased the frequency of this derived haplotype in the population, which is fixed at 30% of ISX insertions and polymorphic among another 41%. Sharing of this haplotype indicates that high levels of gene conversion among ISX elements allow them to ‘crowd-source’ refining mutations, and a refining mutation that occurs at any single ISX element can spread in two dimensions: horizontally across insertion sites by non-allelic gene conversion, and vertically through the population by natural selection. These results describe a novel route by which fully functional regulatory elements can arise rapidly from TEs and implicate non-allelic gene conversion as having an important role in accelerating the evolutionary fine-tuning of regulatory networks.转座子（Transposable elements, TEs）可介导调控网络的重连，近期ISX元件的扩增将77个具备功能但结合效率欠佳的剂量补偿复合体（dosage compensation complex）结合位点分散至果蝇中新形成的X染色体上。本研究鉴定出ISX元件内两个连锁的精细化突变，二者通过上位性互作提升了与剂量补偿复合体的结合亲和力。自然选择使该衍生单倍型在种群中的频率升高，目前该单倍型在30%的ISX插入位点中已固定，另外41%的插入位点呈现多态性。该单倍型的共享现象表明，ISX元件间高水平的非等位基因转换允许它们“众包”精细化突变；任意单个ISX元件上产生的精细化突变可通过两个维度扩散：一是通过非等位基因转换在插入位点间横向传播，二是通过自然选择在种群中纵向扩散。本研究揭示了一条全新的演化路径，即功能性调控元件可由转座子快速产生，并阐明了非等位基因转换在加速调控网络的进化微调中发挥的重要作用。