Molecular Studies of Cospeciation Enhanced by Exhaustive Sampling and GIS Technology

摘要本项目将继续深入探索共同生活了数百万年的两种生物，即咀嚼虱（一种寄生昆虫）和它们的哺乳动物宿主（口袋地鼠）。PI及其同事先前对这种宿主-寄生虫系统的研究为生物体如何长期共生提供了新的见解，并提高了我们对昆虫与哺乳动物分子变化率的认识。该项目将采用一种新的和不同的方法来研究宿主-寄生虫，通过使用gis（地理信息系统）技术来分析以前未探索过的规模的共种。共同发育（宿主和寄生虫的平行物种形成）的分析将使用来自核和线粒体基因的DNA序列。最近开发的方法将用于比较基因、基因组和物种之间的分子进化速率，以确定基因特异性、基因组特异性和谱系特异性差异。GIS技术将用于开发和测试本研究中每种口袋地鼠和每种虱子的预测分布模型（生态位模型）。最后，本项目将在全球虱子数据库（LouseBase）中建立路易斯安那州立大学（LSU）作为活动节点，将本研究过程中产生的所有虱子数据存入该数据库。PI对地鼠-鼠鼠系统的研究中产生的数据继续广泛用于开发分析宿主-寄生虫系统的分析方法和软件（例如，Huelsenbeck & Rannala, 1997； Huelsenbeck等）。, 1997;以及由RodericPage开发的COMPONENT和TREEMAP程序)。这项工作还被至少8本书籍和教科书收录，包括《寄生虫学》（Noble et al., 1989）、《寄生虫的功能生物学》（Esch & & Fernandez, 1993）和《进化》（Ridley, 1996）。因此，这项工作已经达到了大量的研究生和本科生。拟议的项目有一个明确的计划，让学生作为合作者参与研究。这包括路易斯安那州立大学的本科生、研究生和博士后，合作者及其在墨西哥的研究生，以及作为该项目的分包商的北爱荷华大学（UNI）的本科生。UNI的学生将接受基础的、但正在迅速消失的寄生虫分类和鉴定、昆虫显微镜以及使用数字显微镜成像系统进行标本记录和形态分析的培训。学生还将通过在路易斯安那州立大学分子实验室进行为期10天的暑期工作坊，全面了解拟议的研究项目。这些工作坊不仅会训练学生在分子技术方面的研究，还会让他们接触到更大的研究实验室的工作。这种接触和经验对于鼓励优秀学生从事非医学基础研究工作至关重要。

ABSTRACTThis project will continue an in-depth exploration of two organisms thathave lived together for many millions of years, namely chewing lice (a groupof parasitic insects) and their mammalian hosts (pocket gophers). Previousstudies of this host-parasite system by the PI and colleagues have providednew insights into how organisms live in long-term symbiosis and has advancedour knowledge of rates of molecular change in insects versus mammals. Thisproject will take a new and different approach to host-parasite studies byanalyzing cospeciation at a previously unexplored scale augmented by use ofGIS (Geographic Information Systems) technology. Analysis of cophylogeny(parallel speciation in the hosts and parasites) will use DNA sequences fromboth nuclear and mitochondrial genes. Recently developed methods will beused to compare rates of molecular evolution among genes, genomes, andspecies to identify gene-specific, genome-specific, and lineage-specificrate differences. GIS technology will be used to develop and test predictivedistribution models (3ecological niche models2) for each species of pocketgopher and each species of louse examined in this study. Finally, thisproject will establish Louisiana State University (LSU) as an active node inthe worldwide louse database (LouseBase), into which will be deposited alllouse data generated in the course of this research.Data generated in the PI's studies of the gopher-louse system continue to beused widely in development of analytical methods and software for analysisof host-parasite systems (e.g., Huelsenbeck & Rannala, 1997; Huelsenbeck etal., 1997; and the programs COMPONENT and TREEMAP developed by RodericPage). This work has also been featured in at least 8 books and textbooks,including Parasitology (Noble et al., 1989), A Functional Biology ofParasitism (Esch & Fernandez, 1993), and Evolution (Ridley, 1996). Thus,this work has reached a large number of graduate and undergraduate students.The proposed project has an explicit plan to involve students ascollaborators in the research. This includes undergraduates, graduates, andpostdocs at LSU, collaborators and their graduate students in Mexico, andundergraduate students at the University of Northern Iowa (UNI), which is asubcontractor on this project. Students at UNI will be trained in thefundamental, yet rapidly disappearing, skills of parasite taxonomy andidentification, insect microscopy, and use of the digital microscopy imagingsystem for specimen documentation and morphological analysis. Students willalso be exposed to the total breadth of the proposed research programthrough intensive, 10-day, summer workshops in the molecular lab at LSU.These workshops will not only train the students in the molecular techniquesinvolved with the proposed research, but will also expose them to theworkings of a larger research laboratory. This kind of exposure andexperience is essential to encourage quality students to pursue careers innon-medical basic research.