基于核糖体DNA联合序列的天牛总科高阶元分子系统学研究

Molecular phylogenetic study of the higher taxa of the superfamily Cerambycoidea( Insecta: Coleoptera) based on the combined analysis of ribosomal DNA sequences

【目的】利用核糖体DNA联合序列探讨天牛总科高阶元分子系统发育。【方法】本研究采用分子标记技术,分析测定了63种天牛核糖体28S rDNA D2和D3区以及18S rDNA V4和V7区的DNA序列,并采用邻接法、最大似然法和贝叶斯推论法分别构建了天牛总科2科6亚科63种的分子进化系统。【结果】序列联合比对分析,最终得到1 404 bp的联合数据组,其中可变位点446个(32.0%),保守位点958(68.0%),转换/颠换的平均值(R值)为1.73。28S rDNA和18S rDNA以及联合序列的饱和度分析显示碱基突变未达到饱和,说明这些序列适合于分子进化树的构建。利用不同系统发育重建方法得到进化树具有相似拓扑结构,结果支持沟胫天牛亚科、花天牛亚科和天牛亚科为单系群,这与形态学分类结果相似;狭胸天牛独立成为亚科得到了支持。【结论】利用28S rDNA D2和D3区以及18S rDNA V4和V7区联合序列成功构建出了天牛总科高阶元的系统发育树。研究表明联合序列分析是探讨天牛高阶元分类的有效的方法。

【Aim】 To explore the molecular phylogeny of higher taxa of the superfamily Cerambycoidea by using the combined analysis of ribosomal DNA sequences. 【Methods】 Ribosomal 28S rDNA （D2 and D3 region） and 18S rDNA （V4 and V7 region） sequences from total 63 species representing six subfamilies and two families of Cerambycoidea were chosen as the molecular markers and further sequenced. Phylogenetic trees for the two families and six subfamilies of Cerambycoidea were constructed using Neighbor-Jointing （NJ）, Maximum-Likelihood （ML） and Bayesian-Inference （BI） methods. 【Results】 Sequence analysis results indicated that 1 404 sites after alignment consisted of 446 variable sites （32.0%） and 958 conserved sites （68.0%）. The transition versus transversion ratio （R value） was 1.73. Saturation plot indicated that combined analysis had better linear relation than the single gene analysis, suggesting that the base mutations have not reached saturation. Phylogenetic trees based on NJ, ML and BI methods showed similar topology, suggesting that Lamiinae, Cerambycinae and Lepturinae were all monophyletic group, which was consistent with the results of the traditional morphology. Our results supported the subfamilial placement of Philinae. 【Conclusion】 We successfully reconstructed the phylogenetic trees of higher taxa of Cerambycoidea based on 28S rDNA （D2 and D3 region） and 18S rDNA （V4 and V7 region） sequences. This study confirms that the combined analysis of sequences is an effective method for studying the higher taxonomy of longicorn beetles.