用核糖体SSU rDNA全序列对蝗总科(Acridoidea)进行了分子系统学研究.依据测定的8种蝗虫的SSU rDNA全序列(平均1 844 bp),并从GenBank中选取了6种内群种类和2种外群种类的SSU rDNA同源序列,进行序列分析.利用Clustal、MEGA和PHYLIP软件构建分子系统树(距离邻接法Neighbor-Joining,NJ;最小进化法Minimum Evolution).结果显示:(1)蝗总科是一个单系类群;(2)锥头蝗科(Chrotogonidae)和瘤锥蝗科(Pyrgomorphidae)亲缘关系较近,为蝗总科最原始的类群;(3)网翅蝗科(Arcypteridae)和槌角蝗科(Gomphoceridae)有较近的亲缘关系;(4)斑翅蝗科(Oedipodidae)为最进化的类群;(5)SSU rDNA序列保守性强,转换(transition)取代的速率大于或接近颠换(transversion)取代的速率;(6)在系统树中,总科首先分离,大多数同科不同属的类群以高置信度聚合在一起,说明SSU rDNA序列适合用于蝗总科的系统发育关系分析.%Small subunit nuclear ribosomal DNA (SSU rDNA or 18S rDNA) sequences were used to examine the phylogenetic relationships of families of Acridoidea. The SSU rDNA complete sequences (average length 1 844 bp) of the Acridoidea ( include 8 families) were determined, and the homologous sequences of 8 relative species (including 6 species of Acridoidea and 2 species of Tetrigoidea) were retrieved from GenBank. The molecular phylogenetic trees were constructed with software package Clustal X (1.81), MEGA and PHYLIP using Tetrigoidea as outgroup. Based the phylogenetic trees thus obtained, we made the following conclusions: (1) The Acridoidea was supported as a monophyletic group; (2) Pyrgomorphidae and Chrotogonidae were the most ancestral groups; (3) Gomphoceridae and Arcypteridae have closer phylogenetic relationships; (4) Oedipodidae was the most evolved group; (5) The relative frequencies of the four nucleotides were approximately equal ( A: C: G: T = 0. 240: 0. 239 :0.279:0.242), SSU rDNA sequences were conserved and the transition ratio was higher than or approaching to the transversion ratio; (6)Different superfamilies and families were separated, the members of the same family were mostly grouped together,thus, the SSU rDNA sequences can be used as candidate nucleotide sequence for studying the phylogenetic relationships of Acridoidea.
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