奇蝽次目昆虫线粒体基因组学及分类地位的研究

奇蝽次目为半翅目异翅亚目7个次目之一，目前仅知2科400余种。其外部形态与典型的异翅类昆虫相比有不少特化之处，如头分为前后二叶、前翅为膜质而非典型的半鞘翅等，被认为是异翅亚目的基部类群。因此，该次目是研究异翅亚目乃至广义半翅目进化及系统发育的关键类群。异翅亚目高级阶元分类至今仍存在不同观点，奇蝽次目的分类地位则是争论的焦点之一；但这些观点主要基于比较形态学或是少量基因片段的分子系统学的研究，在线粒体基因组水平上的研究尚显不足，对奇蝽次目这一重要类群线粒体基因组的研究几近空白，目前仅有1种奇蝽科线粒体基因组被测序和分析。申请者拟测定该次目代表种的线粒体基因组序列，分析异翅亚目线粒体基因组结构特点，构建其高级阶元的系统发育关系，并推测该类群的起源时间。最后，综合系统发育与线粒体基因组学的结果以及相关生物学习性，探讨奇蝽次目的分类地位及其线粒体基因组加速进化的原因，特别是基因重排的机理。

Enicocephalomorpha, or unique-headed bug, is one of the seven infraorders of Heteroptera, with approximately 400 described species in two families. Members of this lineage are largely different from typical heteropteran insects, with some specialized morphological characters, e.g., a bilobed head and completely membranous wings; and are considered as the basal position of Heteroptera. Consequently, Enicocephalomorpha is a key group to study the evolution and phylogeny of Heteroptera, even the Hemiptera. Despite considerable efforts to reconstruct the phylogeny of Heteroptera, the classification and higher-level systematics of this suborder is clearly an issue of ongoing debate. This controversy concerns in particular the taxonomic status of Enicocephalomorpha. Previous phylogenetic studies of Heteroptera are mainly based on morphological characters or few gene sequences. The relative studies by using mitochondrial genomic data are limited, especially the Enicocephalomorpha with only one complete mitochondrial genome available to date. We try to sequence the mitochondrial genomes of representatives of Enicocephalomorpha, analyze the structural features of heteropteran mitochondrial genomes, reconstruct the higher level phylogeny of Heteroptera and date the origin and radiation. Finally, combined with the results of phylogenetic and mitogenomic analyses and the relative biological characteristics, we will discuss the taxonomic status of Enicocephalomorpha and the cause of accelerated evolution in their mitochondrial genomes, especially the mechanism of gene rearrangement.