Data from: Evolution and Phylogeny of the Diptera: A Molecular Phylogenetic Analysis Using 28S rDNA Sequences

Portions of the large ribosomal subunit RNA gene (28S rDNA) encompassing the D1 and the D7 region were obtained from 16 dipteran species and families to reconstruct early phylogenetic events in the order Diptera. For outgroup comparison, the corresponding sequences were used from representative taxa of the Siphonaptera, Mecoptera, and Lepidoptera. A subset of 488 unambiguously alignable sites was analyzed with respect to important sequence evolution parameters. We found (1) sequence variability is significantly higher in double-stranded sites than in single-stranded sites, (2) transitions are close to saturation in most pairwise sequence comparisons, (3) significant substitution rate heterogeneity exists across sites, and (4) significant substitution rate heterogeneity exists among lineages. Tree reconstruction was carried out with the neighbor joining, maximum parsimony, and maximum likelihood methods. Four major subgroups are consistently and robustly supported: the Brachycera, the Culicomorpha, the Tipulomorpha sensu stricto, and the hitherto controversial Bibionomorpha sensu lato, which includes the families Sciaridae, Mycetophilidae, Cecidomyiidae, Bibionidae, Scatopsidae, and Anisopodidae. The phylogenetic relationships within or among these subclades and the positions of the families Psychodidae and Trichoceridae were not robustly resolved. These results support the view that the mouthparts of extant dipteran larvae evolved from a derived ground state characterized by subdivided and obliquely moving mandibles. Furthermore, sequence divergence and the paleontological record consistently indicate that a period of rapid cladogenesis gave rise to the major dipteran subgroups.

本研究从16个双翅目（Diptera）物种及科级类群中获取了覆盖大亚基核糖体RNA基因（28S rDNA）D1与D7区域的片段，用于重建双翅目目的早期系统发育演化事件。为开展外类群（outgroup）比对分析，我们选取了蚤目（Siphonaptera）、长翅目（Mecoptera）和鳞翅目（Lepidoptera）代表类群的对应序列。最终筛选出488个可明确比对的位点子集，针对关键序列进化参数展开分析。研究结果如下：（1）双链位点的序列变异度显著高于单链位点；（2）多数两两序列比对中，转换（transitions）已接近饱和状态；（3）不同位点间存在显著的替换速率异质性；（4）不同谱系间同样存在显著的替换速率异质性。系统发育树重建采用邻接法（neighbor joining）、最大简约法（maximum parsimony）与最大似然法（maximum likelihood）三种方法。分析结果一致且稳健地支持4个主要演化支：短角亚目（Brachycera）、库蚊总科类群（Culicomorpha）、狭义大蚊总科（Tipulomorpha sensu stricto），以及迄今尚存争议的广义毛蚊总类（Bibionomorpha sensu lato），该类群涵盖眼蕈蚊科（Sciaridae）、菌蚊科（Mycetophilidae）、瘿蚊科（Cecidomyiidae）、毛蚊科（Bibionidae）、扁角菌蚊科（Scatopsidae）与长角沼蝇科（Anisopodidae）。上述亚支内部或亚支间的系统发育关系，以及蛾蠓科（Psychodidae）和毛蠓科（Trichoceridae）的系统发育位置，尚未得到稳健解析。本研究结果支持"现生双翅目幼虫的口器起源于以分节且斜向运动的上颚为特征的衍生祖征"这一观点。此外，序列分化数据与古生物学记录均一致表明，一次快速的分支演化事件催生了双翅目的主要演化支系。