Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, Mississippi, United States of America.
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
PLoS Genet. 2018 Jan 29;14(1):e1007183. doi: 10.1371/journal.pgen.1007183. eCollection 2018 Jan.
House dust mites are common pests with an unusual evolutionary history, being descendants of a parasitic ancestor. Transition to parasitism is frequently accompanied by genome rearrangements, possibly to accommodate the genetic change needed to access new ecology. Transposable element (TE) activity is a source of genomic instability that can trigger large-scale genomic alterations. Eukaryotes have multiple transposon control mechanisms, one of which is RNA interference (RNAi). Investigation of the dust mite genome failed to identify a major RNAi pathway: the Piwi-associated RNA (piRNA) pathway, which has been replaced by a novel small-interfering RNA (siRNA)-like pathway. Co-opting of piRNA function by dust mite siRNAs is extensive, including establishment of TE control master loci that produce siRNAs. Interestingly, other members of the Acari have piRNAs indicating loss of this mechanism in dust mites is a recent event. Flux of RNAi-mediated control of TEs highlights the unusual arc of dust mite evolution.
尘螨是一种常见的害虫，具有不寻常的进化历史，是寄生祖先的后代。向寄生的转变通常伴随着基因组重排，可能是为了适应获得新生态所需的遗传变化。转座元件（TE）的活性是基因组不稳定的一个来源，它可以引发大规模的基因组改变。真核生物有多种转座子控制机制，其中一种是 RNA 干扰（RNAi）。对尘螨基因组的研究未能确定一个主要的 RNAi 途径：Piwi 相关 RNA（piRNA）途径，该途径已被一种新的类似小干扰 RNA（siRNA）的途径所取代。尘螨的 siRNA 广泛地篡夺了 piRNA 的功能，包括建立产生 siRNA 的 TE 控制主位点。有趣的是，节肢动物的其他成员也有 piRNA，这表明尘螨中这种机制的丧失是最近发生的事件。RNAi 介导的 TEs 控制的通量突出了尘螨进化的不寻常轨迹。
