Hox基因家族进化图谱与单殖吸虫高级阶元系统演化

单殖吸虫为一类主要寄生于水生脊椎动物体外的蠕虫，是扁形动物由自由生活向内寄生生活演化的中间过渡类群。单殖吸虫高级阶元系统演化研究对理解寄生方式的起源与进化具重要价值。目前，单殖吸虫在新皮类动物中的位置，以及多钩亚纲内各目间的系统关系尚有较大争议。我们前期的转录组数据证实单殖吸虫为非单系群。本项目将完成单殖吸虫8个目13个代表种的转录组测序，并结合RACE、PCR等技术系统性解析Hox基因在单殖吸虫代表属种中的种类组成、基因数量、序列结构，揭示Hox基因在单殖吸虫中的分化模式，并综合谱系基因组学和Hox基因分子系统学构建单殖吸虫目阶系统演化关系，进一步探讨单殖吸虫在新皮类动物中的分类地位。研究结果将为单殖吸虫高级阶元系统演化提供全新的研究例证，对理解Hox基因家族在扁形动物中的起源与演化具参考价值，同时为后续Hox基因在单殖吸虫形态多样性构建和寄生适应性中的功能机制研究奠定基础。

Monogeneans, ecto-parasitic worms on aquatic vertebrates, is an evolutionary intermediate group of flatworms that evolved from free-living to endo-parasitism. Assessing phylogenetic relationship among higher taxa in class Monogenea is vital to our understanding of the origin and evolution of parasitism. However, the taxonomy position of Monogenea in the Neodermata (a group of Monogenea, Cestoda and Trematoda), as well as the interrelationships among orders of subclass Polyonchoinea, has long been controversial. Our earlier transcriptome data confirmed that Monogenea is a non-monophyletic group. In this project, we will firstly complete the transcriptome sequencing of 13 representative species in 8 orders of Monogenea, then analyze the gene composition, gene number and sequence structure of the Hox gene family in the representative monogeneans through combining bioinformatics and RACE, PCR methods, and finally construct the phylogenetic relationship at the class-level or order-level based on phylogenomics and Hox gene molecular phylogeny. The results of this study will provide a strong new evidence on the higher taxa phylogeny and reveal the evolutionary map of the Hox gene in Monogenea,which is benefit for us to the follow-up studies on the molecular mechanism of Hox gene in morphological construction during the parasitic adaptation process.