Origin and evolution of the major lineages of Bryozoa: Nuclear rDNA based high-level phylogeny of Stenolaemata, Gymnolaemata and Phylactolaemata

苔藓虫是一个知之甚少的动物群体，尽管它们有大量的古生物记录和所有主要谱系的现代存在。由于缺乏行之有效的方法，分子系统发育学几乎没有开始阐明门。最近，我们建立并初步测试了一种扩增海洋苔藓虫18S rDNA 1500 bp片段和28S rDNA 900 bp片段的方法。目的是利用18S和28S rDNA序列，结合古生物资料，阐明海洋苔藓虫（Cyclostomata、Ctenostomata和Cheilostomata）所有主要类群的起源和演化。此外，淡水苔藓虫（Phylactolaemata）将包括在分析中。分子钟假说将被应用于粗略估计苔藓虫的分化时间，并测试几个假设，这是理解苔藓虫进化的基础。

Bryozoa are a poorly understood animal group despite their huge palaeontologic record and the modern presence of all main lineages. Molecular phylogenetics has scarcely begun to elucidate the phylum due to the absence of well-working methods. Recently, we have established and preliminary tested a method allowing the amplification of 1500 bp fragments of 18S rDNA and 900 bp of 28S rDNA of marine bryozoans. The aim is to elucidate the origin and evolution of all tree main groups of marine Bryozoa (Cyclostomata, Ctenostomata and Cheilostomata) using 18S and 28S rDNA sequences in combination with paleontologic data. Additionally, freshwater Bryozoa (Phylactolaemata) will be included in the analyses. Molecular clock hypothesis will be applied to roughly estimate times of divergence in Bryozoa and to test several hypotheses, basic for understanding bryozoan evolution.