基于28S rRNA基因序列的常见有瓣蝇类的系统发育

用中国产双翅目有瓣蝇类6科15种和GenBank中登录的5科6种有瓣蝇类昆虫的28SrDNA序列片段组合成7科21种,进行同源性比较。应用Mega3.0软件,探讨了28S rRNA基因在有瓣蝇类的分子进化机制;以黑腹果蝇Drosophilia melanogaster为外群,NJ和MP法构建了上述类群的分子系统树。研究结果表明:在获得的698bp的序列中,有126个变异位点,101个简约信息位点;A T含量平均为68.8%,存在较强的A T含量偏向性。分子系统树中,所有内群聚为一支,支持有瓣蝇类为一单系。内群分别聚为2大支:丽蝇科和麻蝇科关系较近于寄蝇科,组成较进化的狂蝇总科;蝇科与花蝇科聚合的类群为蝇总科,上述结果与现代形态分类系统相同。但粪蝇科和厕蝇科脱离蝇总科,与狂蝇总科聚为一支,与现代形态分类系统不一致。

Phylogenetic Relationships of Common Calyptratae Flies(Insecta:Diptera) Based on Sequences of 28 S rRNA Gene

The sequences for partial 28S rRNA gene were determined for 15 species from 6 Calyptrate families in China, and the homologous of partial 28S rRNA sequences for 6 species of 5 Calyptrate families from the GenBank, their combination results in a tree representing 7 Calyptrate families. With the help of Mega3.0 software, the molecular phylogenetic trees under maximum parsimony (MP) and neighbour-joining (NJ) methods were reconstructed using Drosophilia melanogaster as outgroup. The results showed that there were 126 variable sites and 101 parsimony-informative sites in the nucleotides of the data, and the average A T content of 28S rRNA gene in Calyptrae was 68.8% which showed a strong A T bias. Molecular phylogenetic trees indicated that the monophyly of Calyptratae was well supported, Calyptrae were divided into two main clades in this study, Sarcophagidae were related to Calliphoridae rather than to Tachinidae. They were composed of a higher superfamily Oestroidea; Muscidae and Anthomyiidae were grouped into a group of superfamily Muscoidea. All above results matched the classical morphological taxonomy reasonably well. But Scathophagidae and Fanniidae displayed a tendency to cluster within Oestroidea. This result was significant incongruence with classical morphological taxonomy.