Molecular Studies of Cophylogeny: Microbes, Insects, and Mammals

DEB-0075381Mark S.哈夫纳博士Mark S.哈夫纳是路易斯安那州州立大学的动物学家，沿着同一所大学的微生物学家弗雷德里克·雷尼博士和内奥米·沃德-雷尼博士获得了一笔赠款，用于研究三种共生生物的共同进化史：一种叫做囊地鼠的小型啮齿动物，一种生活在囊地鼠皮毛中的虱子，以及一种生活在虱子内部的细菌的选定谱系。 哈夫纳和他的其他同事先前的研究已经确定，囊地鼠和他们的虱子已经生活在一起数百万年了，导致囊地鼠和虱子的家谱几乎相同。 在场合作小组现在建议使用分子方法，包括检查DNA和RNA，以确定生活在虱子内的细菌是否也与其宿主有着悠久的联系历史。这个为期2年的项目的主要目标是表征虱子内的细菌群落，并区分或多或少永久性地生活在虱子内的细菌谱系与那些仅仅是通过虱子消化道的短暂细菌谱系。 这项研究将需要仔细检查和比较内虱和外虱（地鼠相关和自由生活）的细菌群落;因此，这项研究的一个重要副产品将是表征与整个口袋地鼠洞穴系统相关的微生物群落。 实验方法将包括三个方面的证据：虱子内微生物群落的显微镜可视化，细菌谱系的培养和DNA测序，以及细菌多样性的独立于培养的分子分析。最终，细菌与其宿主之间长期关联的记录将允许比较这两个远亲群体的遗传变化率。

DEB-0075381Mark S. HafnerDr. Mark S. Hafner, a zoologist at Louisiana State University, along with microbiologists Drs. Frederick Rainey and Naomi Ward-Rainey at the same institution have been awarded a grant to investigate the shared evolutionary history of three symbiotic organisms: small rodents called pocket gophers, the lice that live in the fur of the pocket gophers, and selected lineages of bacteria that live inside the lice. Previous research by Hafner his other colleagues has established that the pocket gophers and their lice have been living together for millions of years, resulting in nearly identical phylogenies (family trees) for the gophers and lice. The presence collaborative team now proposes to use molecular methods, including examination of DNA and RNA, to determine if the bacteria that live inside the lice also have shared a long history of association with their hosts. The major goal of this 2-year project is to characterize the bacterial community living inside the lice, and distinguish between lineages of bacteria that live more-or-less permanently inside the lice versus those that are mere transients passing through the louse's digestive tract. This research will require careful examination and comparison of both intra-louse and extra-louse (gopher-associated and free-living) bacterial communities; hence, an important byproduct of this research will be characterization of the microbial communities associated with the entire pocket gopher burrow system. The experimental approach will incorporate three lines of evidence: microscopic visualization of microbial communities inside the lice, culturing and DNA sequencing of bacterial lineages, and culture-independent molecular analyses of bacterial diversity. Ultimately, documentation of a long-term association between the bacteria and their hosts will allow for comparison of rates of genetic change in these two distantly related groups.