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，尽管他们巨大的古生物学记录和所有主要谱系的现代存在。由于缺乏良好的工作方法，分子生物遗传学几乎没有开始阐明该门。最近，我们建立了一种扩增海洋苔藓动物18SrDNA的1500 bp片段和28SrDNA的900 bp片段的方法，并进行了初步试验。利用18S和28S rDNA序列，结合古生物学资料，对环口门、栉口门和唇口门3个主要类群的起源和演化进行了研究。此外，淡水苔藓虫（Phylactolaemata）也将纳入分析。分子钟假说将被用来粗略估计苔藓动物的分化时间，并检验几个假说，为了解苔藓动物的进化奠定基础。

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.