Phylogeny and evolution of Monoplacophora and basal Mollusca reconstructed by morphological and molecular data sets

来自化石的新证据，以及微观解剖学和分子遗传学的结果，对教科书上关于主要软体动物群体的起源和关系的知识提出了挑战。被称为“活化石”的单placophora （Tryblidia）可能是了解早期软体动物进化的关键。然而，它们是动物领域中拥有最少序列数据的最后一类动物，因此是系统学家最想要的研究对象之一。提取的优质DNA和三个物种（Micropilina sp., Neopilinidae sp., Laevipilina antarctica）的第一序列可供申请人使用，进一步的物种将被搜索。本项目将利用1)保守的标准序列标记（完整的18S和28S rDNA以及组蛋白3基因），2)线粒体基因组学（特别是基因排列），3)hox基因调查，以及4)将作为新标记探索的有助于壳形成的基因来分析单placophorans和其他基础软体动物群体的选定成员。相比之下，鲜为人知的基础软体动物的结构将被检查，并将建立一个非常大的形态学数据集，并分析系统发育。探讨热议的基础软体动物系统发育将有助于更好地理解软体动物、软体动物外壳和其他器官如序列重复结构的起源和进化。

New evidences from fossils, as well as microanatomical and molecular genetic results, have challenged textbook knowledge regarding the origin and relationships of major molluscan groups. The Monoplacophora (Tryblidia), which are famous as “living fossils”, could be the key to understanding the early molluscan evolution. However, they represent one of the last classes in the animal realm with minimum sequence data available, and thus are amongst the most wanted study objects by systematists. Extracted quality DNA and first sequences of three species (Micropilina sp., Neopilinidae sp., Laevipilina antarctica) are available to the applicant, and further species will be searched for. The here proposed project shall analyse monoplacophorans and other selected members of basal molluscan groups using 1) conservative standard sequence markers (complete 18S and 28S rDNA and Histone 3 gene), 2) mitochondrial genomics (especially gene arrangements), 3) a survey of hox genes, and 4) genes contributing to shell formation that will be explored as novel markers. Comparatively, structures of poorly known basal molluscs will be examined, and a very large set of morphological data will be established and analyzed phylogenetically. Exploring the hotly debated basal molluscan phylogeny will contribute to a better understanding of the origin and evolution of Mollusca, the molluscan shell, and other organs such as serially repeated structures.