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

摘要DEB-0237175 A基金已授予沃尔特R。Hoeh博士在肯特州立大学研究淡水贻贝（双壳类）族Lampsilini的分子系统学和线粒体DNA（mtDNA）遗传。 线粒体DNA的双单亲遗传已在海洋和淡水贻贝中发现。 这一系统在海洋贻贝中得到了广泛的研究，但在物种丰富的淡水动物群中的研究相对较少。 双单亲遗传系统的研究表明，mtDNA的性别转换事件是常见的海洋贻贝，然而，最近的工作表明，这些性别转换事件是不存在的淡水贻贝。 这种情况可能与淡水蚌雄传mtDNA中COII基因的600个核苷酸的延伸有关。 使用DNA测序技术，该项目将研究的COII延伸的Lampsilini，一组淡水贻贝，特别感兴趣的，因为它包含了一些最有趣的形态适应双壳类，以及二次减少的COII延伸在这个部落内的一个物种的进化。 该项目的具体目标包括：（1）构建对lampsiline遗传学的可靠估计，（2）调查COII延伸减少的进化模式，以及（3）检查男性和女性传播的mtDNA的分子进化。 这些目标将有助于测试lampsiline进化关系，确定COII延伸的不稳定性，确定COII延伸阻止性别转换的程度，并增加我们对分子进化变化背后的力量的理解。 这些具体目标的完成具有广泛的意义，包括：淡水贻贝，在世界上最危险的动物群之一的保护;双单亲和标准的母系mtDNA遗传的进化;形态性二型性的Lampsilini的进化;和分子进化的机制。 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.