Pashley D P, McPheron B A, Zimmer E A
Entomology Department, Louisiana State University, Baton Rouge 70803.
Mol Phylogenet Evol. 1993 Jun;2(2):132-42. doi: 10.1006/mpev.1993.1013.
Phylogenetic relationships of 19 species representing nine holometabolous insect orders and three outgroup orders were examined using sequence data from two-thirds of the 18S nuclear ribosomal RNA molecule. Of 1330 aligned nucleotide sites in 19 taxa, 460 were variable and used for phylogenetic analysis. Parsimony analyses resolved relationships in a few groups but left the most controversial questions regarding relationships among major lineages unresolved. All analyses supported a clade with Lepidoptera and Trichoptera as sister taxa most closely related to Diptera. Mecoptera and Siphonaptera were most often linked basally to this group, supporting the existence of the Mecopterida superorder. Phylogenetic affinities of this superorder and remaining lineages, Coleoptera, Hymenoptera, and neuropterids, were ambiguous. In contrast, distance analysis produced a tree supporting one of three morphologically based hypotheses. Neuroptera and Hymenoptera were placed as sister taxa ancestral to Mecopterida, with Coleoptera basal to all orders. The inability of the 18S molecule to resolve ancient divergence events may be due to the rapid divergence of holometabolous orders, resulting in few synapomorphies.
利用18S核糖体RNA分子三分之二的序列数据，研究了代表9个全变态昆虫目和3个外群目的19个物种的系统发育关系。在19个分类单元的1330个比对核苷酸位点中，有460个是可变的，并用于系统发育分析。简约分析解决了一些类群中的关系，但关于主要谱系之间关系的最具争议性的问题仍未解决。所有分析都支持一个分支，其中鳞翅目和毛翅目作为姐妹类群，与双翅目关系最为密切。长翅目和蚤目最常从基部与该类群相连，支持了长翅总目的存在。这个总目与其余谱系（鞘翅目、膜翅目和脉翅类）的系统发育亲缘关系尚不明确。相比之下，距离分析产生了一棵树，支持了基于形态学的三个假设之一。脉翅目和膜翅目被置于长翅总目祖先的姐妹类群位置，鞘翅目在所有目之前。18S分子无法解决古老的分化事件，可能是由于全变态目的快速分化，导致很少有共衍征。
