中文摘要：

Transposable 元素(TE ) 是能在染色体以内移动的 DNA 序列。TE 极大地通过许多机制塑造了主人有机体的染色体， transcriptomes，和 proteomes。然而， TE 通常破坏基因并且使动摇宿主染色体，它实质地减少宿主有机体的健康。理解 genomic 分发和 TE 的进化动力学将极大地加深我们调停 TE 的生物过程的理解。大多数 TE 插入在果蝇 melanogaster 是高度多态的，提供我们在人口水平调查 TE 的进化的一个好系统。理论、试验性的研究的十年很好建立了调换选择人口遗传模型，它假设在 TE 复制和净化的选择之间的平衡在染色体决定 TE 的拷贝数字。在最后十年， P-element-induced 懦弱睾丸(PIWI ) 交往的 RNA (piRNAs ) 被表明是在果蝇的 TE 活动的主人抑压者。piRNAs 的发现革命化了我们 TE 压抑的理解，因为它表明主人有机体发展了适应机制对 TE 侵略保卫。巨大的进步被取得了理解由哪个 piRNAs 镇压的分子的机制活跃 TE，尽管在这个过程的许多细节尚待进一步被探索。在 piRNAs 和 TE 之间的相互作用很好解释在果蝇为红外和下午系统位于混合 dysgenesis 下面的分子的机制，它难倒进化生物学家十年了。piRNA 压抑小径提供我们学习在寄生虫和主机有机体之间的 co 进化的进程的一个无匹的系统。

英文摘要：

Transposable elements （TEs） are DNA sequences that can move within the genome. TEs have greatly shaped the genomes, transcriptomes, and proteomes of the host organisms through a variety of mechanisms. However, TEs generally disrupt genes and destabilize the host genomes, which substantially reduce fitness of the host organisms. Understanding the genomic distribution and evolutionary dynamics of TEs will greatly deepen our understanding of the TE-mediated bio- logical processes. Most TE insertions are highly polymorphic in Drosophila melanogaster, providing us a good system to investigate the evolution of TEs at the population level. Decades of theoretical and experimental studies have well established ＂transposition-selection＂ population genetics model, which assumes that the equilibrium between TE replication and purifying selection determines the copy number of TEs in the genome. In the last decade, P-element-induced wimpy testis （PIW1）- interacting RNAs （piRNAs） were demonstrated to be master repressors of TE activities in Droso- phila, The discovery of piRNAs revolutionized our understanding of TE repression, because it reveals that the host organisms have evolved an adaptive mechanism to defend against TE invasion. Tremendous progress has been made to understand the molecular mechanisms by which piRNAs repress active TEs, although many details in this process remain to be further explored. The inter- action between piRNAs and TEs well explains the molecular mechanisms underlying hybrid dysge- nesis for the IoR and P-M systems in Drosophila, which have puzzled evolutionary biologists for decades. The piRNA repression pathway provides us an unparalleled system to study the co-evolutionary process between parasites and host organisms.