Transposable elements (TEs) are mobile genetic parasites that can exponentially increase their genomic abundance through self-propagation. Classic theoretical papers highlighted the importance of two potentially escalating forces that oppose TE spread: regulated transposition and purifying selection. Here, we review new insights into mechanisms of TE regulation and purifying selection, which reveal the remarkable foresight of these theoretical models. We further highlight emergent connections between transcriptional control enacted by small RNAs and the contribution of TE insertions to structural mutation and host-gene regulation. Finally, we call for increased comparative analysis of TE dynamics and fitness effects, as well as host control mechanisms, to reveal how interconnected forces shape the differential prevalence and distribution of TEs across the tree of life.

转座因子（TEs）是可移动的遗传寄生虫，可通过自我繁殖以指数方式增加其基因组丰度。经典的理论论文强调了对抗TE传播的两种潜在升级力量的重要性：调节的换位和纯化选择。在这里，我们回顾了对TE调控和纯化选择机制的新见解，揭示了这些理论模型的非凡远见。我们进一步强调了小RNA转录调控与TE插入对结构突变和宿主基因调控的贡献之间的新兴联系。最后，我们呼吁加强对TE动态和适应性效果以及宿主控制机制的比较分析，