基于线粒体基因组数据的扁甲系总科间系统发育关系分析

Phylogenetic relationships among superfamilies of Cucujiformia (Coleoptera: Polyphaga) inferred from mitogenomic data

扁甲系是鞘翅目多食亚目中最大的一个类群,具有重要的经济意义.尽管扁甲系昆虫的单系性得到广泛支持,但7个总科间的系统进化关系仍存在不确定性.为此,本研究测定了锈赤扁谷盗和锯谷盗的线粒体基因组,并联合已测的67个扁甲系昆虫线粒体基因组,构建了扁甲系昆虫总科间的系统发育关系,并采用似然值检验对不同的树拓扑结构进行了评价.结果表明,锈赤扁谷盗全线粒体基因组的大小为15497 bp,编码13个蛋白质编码基因、22个转运RNA基因和2个核糖体RNA基因.锯谷盗接近全长的线粒体基因长为13588 bp,编码34个基因,缺少trnI, trnQ和trnM等3个转运RNA基因.锈赤扁谷盗和锯谷盗线粒体基因的基因含量、基因排序、碱基组成、密码子使用等特征,与大多数已测鞘翅目昆虫的线粒体基因组高度相似.基于3个线粒体基因数据集及3种树构建方法的系统发育分析结果表明,瓢虫总科、叶甲总科、象甲总科、拟步甲总科和郭公虫总科等5个类群均为单系性,而扁甲总科始终为并系.树拓扑结构检验结果表明,扁甲系总科间的系统发育关系为((郭公虫总科+瓢虫总科)+(拟步甲总科+(扁甲总科(叶甲总科+象甲总科)))).尽管线粒体数据集的构成及系统发育分析方法对树拓扑结构具有重要影响,但线粒体基因组数据在扁甲系昆虫系统与进化研究方面具有重要应用价值.

Cucujiformia is the largest group in the Polyphaga of the Coleoptera, most of which are of economic importance. Although the monophyly of Cucujiformia has been widely supported, the phylogenetic relationships among seven superfamilies within Cucujiformia remain unresolved. In this study, mitochondrial genomes(mitogenomes) of Cryptolestes ferrugineus and Oryzaephilus surinamensis were sequenced. Combined with other 67 sequenced coleopteran mitogenomes, we reconstructed phylogenetic relationships among superfamilies of Cucujiformia and evaluated tree topologies by likelihood value tests. The results showed that the complete mitogenome of C. ferrugineus was 15497 bp long and encoded 13 protein-coding genes, 22 transfer RNA genes(tRNAs)and two ribosomal genes. The near complete mitogenome of O. surinamensis was 13588 bp long and encoded 34 mitochondrial genes, lacking three tRNAs(trnI, trnQ and trnM). General features of the two newly sequenced mitogenomes(gene content, gene arrangement, base composition and codon usage) were highly similar to that of previously sequenced beetles. Phylogenetic analyses based on three mitogenomic data and three analytical methods supported the monophyly of each of five superfamilies(Coccinelloidea, Chrysomeloidea, Curculionoidea, Tenebrionoidea and Cleroidea). The monophyly of Cucujoidea was never recovered in all the nine phylogenetic analyses. Tree topology tests statistically supported the superfamily-level relationships in Cucujiformia:((Cleroidea+Coccinelloidea)+(Tenebrionoidea+(Cucujoidea(Chrysomeloidea+Curculionoidea)))). Although both mitogenomic datasets and analytical methods have an important impact on tree topologies, mitogenomic data have important implications in evolutionary and phylogenetic studies of Cucujiformia.