转录组测序筛选核DNA序列标记重建"螽斯"系统进化史

"螽斯"包括原螽、螽斯、驼螽、沙螽等类群,相当于螽次亚目。这些类群间系统进化关系不清，可选用的核DNA序列标记有限。本项目利用Illumina HiSeq 2000测定5种"螽斯"雄性成体转录组，预期每种获得4Gb数据。通过与实验室之前测定的优雅蝈螽转录组、公共数据库相关数据比较，识别种间直系同源基因。计算长度超过500bp核基因种间序列分歧，选出进化速率适宜的核DNA序列标记。设计引物进行PCR验证，选择100个以上扩增效果良好的核DNA序列标记，并对由"螽斯"各类群选出的50个左右代表种扩增测序。采用超矩阵和超树分析策略，构建稳健可靠的"螽斯"高级阶元系统进化关系。采用比较转录组学方法实现核DNA序列标记高通量筛选，并在更多代表种中对这些核DNA序列标记进行扩增测序。研究结果不仅可重建"螽斯"系统进化史，追溯其声通讯起源与进化，而且为直翅目其他类群系统进化研究提供大量核DNA序列标记。

Katydids correspond to the infraorder Tettigoniidea (Vickery 1979), consisting of Hagloidea, Tettigonioidea, Stenopelmatoidea, Rhaphidophoroidea, etc. The phylogenetic relationships among these taxonomic groups are still not clear. Only few nuclear DNA markers can be used for their phylogenetic relationship studies. The Illumian HiSeq 2000 will be applied for transcriptome sequencing male adults of 5 katydid species and the deep sequencing will produce about 4 Gb transcriptomic data per sample. The orthologous genes will be identifed by comparing with 7 longhorn grasshopper species transcriptome data, including previous sequenced Gampsocleis gratiosa (katydid), Gryllus bimaculatus (cricket) transcriptome data and Lucosta migratoria genome data in public database, and the sequence divergence of the nuclear loci with more than 500 bp in size will be evaluated. New primer pairs will be designed for PCR amplification testing of those nuclear loci which are suitable for deeper-level phylogenetic reconstruction across the major groups of katydids and outgroup cricket. To fully resolve katydids deeper-level phylogenetic relationships, 100 effective amplification nuclear DNA markers will be amplified and sequenced in about 50 species from major groups of katydids. This project is the first time based on comparative transcriptomics approach for high-throughput identify new nuclear DNA markers which suitable for katydid deeper-level phylogenetic study. The results can not only solve the katydid deeper-level phylogenetic relationships and infer the origin and evolution of katydid acoustic communication, but also provide a large number of new nuclear DNA markers for Orthoptera phylogenetic relationship studies.