鸟虱关键类群的线粒体基因组及系统发育研究

There are approximately 5000 species of parasitic lice in four suborders and 24 families in the order Phthiraptera. Lice are permanent, obligate ectoparasites of birds and mammals, feeding on the leather, debris or the blood. Nearly 4000 species of lice parasitize birds. The spread and infestation of bird lice have already impacted the poultry industry and the conservation of endangered birds. Extensive gene rearrangements, even genome fragmentation, have been found in these species and Phthiraptera become a key group to study the evolution of mitochondrial genomes. However, the relative studies by using mitochondrial genomic data in bird lice are limited, with only seven mitochondrial genomes available to date. In this project, we propose to explore the diversity of mitochondrial genomic organization of key groups in bird lice and reconstruct the higher level phylogeny of Phthiraptera with next-generation sequencing technology. Combined with methods from the comparative genomics and bioinformatics, we will analyze the evolutionary pattern of structure features in bird lice mitochondrial genomes. The results will help to better understand the diversity of mitochondrial genomes in bird lice, and also provide theoretical significance for understanding the evolution of insect mitochondrial genomes.

虱目目前已知4亚目24科5000余种，全部营寄生生活，取食寄主的毛发、皮屑或血液；其中约4000多种寄生虱寄生于鸟类，被称为鸟虱。鸟虱的侵染和扩散严重影响着家禽养殖业和濒危野生鸟类的保护。虱目昆虫的线粒体基因组存在基因重排甚至基因组裂化的现象，是研究线粒体基因组结构进化的关键类群。但是目前针对鸟虱线粒体基因组的研究还比较有限，仅有7种鸟虱的线粒体基因组被测序和分析。本项目拟利用高通量测序的方法对鸟虱关键类群的线粒体基因组进行测序，分析鸟虱线粒体基因组的基因重排方式和结构特点，构建虱目高级阶元的系统发育关系。在这些基础上，通过比较基因组学和生物信息学方法，探讨鸟虱线粒体基因组结构的进化机制。研究结果将有助于了解鸟虱线粒体基因组的多样性，对理解虱目昆虫线粒体基因组的进化有重要的理论意义。

虱目目前已知5000余种，全部营寄生生活，取食寄主的毛发、皮屑或血液；其中约4000多种寄生虱寄生于鸟类，被称为鸟虱。鸟虱的侵染和扩散严重影响着家禽养殖业和濒危野生鸟类的保护。虱目昆虫的线粒体基因组存在基因重排甚至基因组裂化的现象，是研究线粒体基因组结构进化的关键类群。本项目利用高通量测序技术完成了25种鸟虱线粒体基因组的测定和分析，首次发现鸟虱中存在线粒体基因组的裂化现象，且裂化程度差异较大。利用线粒体基因组数据重建了虱目高级阶元间的系统发育关系，进一步支持丝角亚目为并系群。鸟虱线粒体基因组发生了剧烈的基因重排，重排模式在亚目和科级层面无明显规律，但在部分属内相对保守。倒置的基因簇ND4L-ND4很可能是短角鸟虱科物种的共有衍征，同时此基因簇在整个钝角亚目内都较为保守。这些结果进一步揭示了虱目昆虫线粒体基因组结构的多样性，为深入理解昆虫线粒体基因组结构进化以及解决虱目高级阶元的系统发育关系奠定了基础。