基于5.8S rDNA序列论三白草科的系统发育

The Phylogeny of Saururaceae Based on 5.8S rDNA Sequences

三白草科 (Saururaceae)是古草本的一个核心类群 ,它的研究对被子植物起源和早期演化具有重要意义。本文采用最大简约法 (maximumparsimonymethod)和邻接法 (neighbor -join ingmethod)等不同的分析方法 ,对三白草科及其外类群齐头绒 (ZippeliabegoniaefoliaBlume)的 5 8SrDNA序列进行分析 ,得到一致的结论 :Anemopsis最早从三白草科中分离出来 ,Sauru ruschinensis和S .cernuus是一对姐妹群 ,由于 5 8SrDNA序列的变异位点和信息位点相对比较少 ,Gymnothecachinensis—G .involucrata—Houttuynia—Saururus之间难以通过 5 8SrDNA序列的比较进行分辩。

Saururaceae is a core component of paleoherbs, and is very important for studying the origin and development of early angiosperms. By using different analysis method, such as the maximum parsimony method and the neighbor-joining method, we analyzed the 5 8S rDNA sequences of Saururaceae and the outgroup Zippelia begoniaefolia Blume. The conclusions are the similar, that is, Anemopsis departs from Saururaceae at first, Saururus chinensis is the sister to S. cernuus . However, it is difficult to differt the Gymno theca chinensis - G. involucrata - Houttuynia - Saururus clade by using 5 8S rDNA sequences.