Molecular Systematics of the Lampsilini (Bivalvia: Unionoida): Evolution of Ancient Sex-Specific Extension of the cytochrome c oxidase II Gene

摘要美国肯特州立大学Walter R. Hoeh博士获得deb - 0237175A基金资助，研究淡水贻贝（双壳类）部落Lampsilini的分子系统和线粒体DNA （mtDNA）遗传。在海洋和淡水贻贝中发现了双单代遗传mtDNA。这一系统已在海洋贻贝中进行了广泛的研究，但在物种丰富的淡水动物群中进行的研究相对较少。双单代遗传系统的研究表明，mtDNA性别转换事件在贻贝中很常见；然而，最近的研究表明，淡水贻贝中没有这些性别转换事件。这种情况可能与淡水贻贝雄性传播mtDNA中COII基因的600个核苷酸延伸有关。利用DNA测序技术，该项目将研究lamsilini中COII延伸的进化，lamsilini是一组淡水贻贝，特别令人感兴趣，因为它包含了双壳类中一些最有趣的形态适应，以及该部落中一个物种COII延伸的二次减少。该项目的具体目标包括：(1)构建可靠的lampsiline系统发育估计；(2)研究COII延伸减少的进化模式；(3)研究男性和女性传播的mtdna的分子进化。这些目标将有助于测试灯酰胺进化关系，确定COII扩展的不稳定性，确定COII扩展在多大程度上阻止性别转换，并增加我们对分子进化变化背后力量的理解。这些具体目标的完成具有广泛的影响，包括：保护淡水贻贝，这是世界上最濒危的动物之一；双单亲和标准母体mtDNA遗传的进化；蓝茅属植物两性形态二态性的进化以及分子进化的机制。此外，拟议的研究将为年轻的进化论者/系统论者提供培训。

AbstractDEB - 0237175A grant has been awarded to Dr. Walter R. Hoeh at Kent State University to study the molecular systematics and mitochondrial DNA (mtDNA) inheritance in the freshwater mussel (bivalve) tribe Lampsilini. Doubly-uniparental inheritance of mtDNA has been found in marine and freshwater mussels. This system has been studied extensively in marine mussels but relatively little work has been done on the species-rich freshwater fauna. Studies of the doubly-uniparental inheritance system indicate that mtDNA gender-switching events are common in marine mussels; however, recent work suggests that these gender-switching events are absent in freshwater mussels. This situation may be related to a 600 nucleotide extension of the COII gene in freshwater mussel male-transmitted mtDNA. Using DNA sequencing techniques, this project will examine the evolution of the COII extension in the Lampsilini, a group of freshwater mussels that are of particular interest because it contains some of the most interesting morphological adaptations within bivalves as well as a secondary reduction of the COII extension in a species within this tribe. This project's specific objectives include: (1) construct robust estimates of lampsiline phylogeny, (2) investigate the evolutionary pattern of reduction of the COII extension, and (3) examine the molecular evolution of the male- and female-transmitted mtDNAs. These objectives will facilitate tests of lampsiline evolutionary relationships, determine the lability of the COII extension, determine the extent to which the COII extension prevents gender-switching, and increase our understanding of the forces underlying molecular evolutionary change. The completion of these specific objectives has broad implications, including: conservation of freshwater mussels, one of the most imperiled faunas in the world; the evolution of doubly-uniparental and standard maternal mtDNA inheritance; evolution of morphological sexual dimorphism in the Lampsilini; and mechanisms underlying molecular evolution. In addition, the proposed research will provide training for a young evolutionist/systematist.