Molecular Studies of Cospeciation Enhanced by Exhaustive Sampling and GIS Technology

这个项目将继续深入探索生活在一起数百万年的两种生物，即口虱(一组寄生昆虫)和它们的哺乳动物宿主(口袋地鼠)。PI和他的同事之前对这种宿主-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，并促进了我们对昆虫与哺乳动物分子变化率的了解。这个项目将采用一种新的和不同的方法来研究宿主-寄生虫，通过利用地理信息系统(地理信息系统)技术在以前从未探索的规模上分析共种作用。对共生发育的分析(宿主和寄生虫中的平行物种形成)将使用核基因和线粒体基因的DNA序列。最近开发的方法将被用来比较基因、基因组和物种之间的分子进化速度，以确定基因特定的、基因组特定的和谱系特定的差异。本研究将利用地理信息系统技术建立和检验每一种袋鼠和每一种虱子的预测分布模型(3个生态位模型2)。最后，该项目将建立路易斯安那州立大学(LSU)作为全球虱子数据库(LouseBase)中的活跃节点，其中将存储在研究过程中产生的所有虱子数据。PI对地鼠虱子系统的研究中产生的数据继续广泛用于开发用于分析宿主-寄生虫系统的分析方法和软件(例如，Huelsenbeck&Amp；Rannala，1997；Huelsenbeck等人，1997；以及RodericPage开发的程序Component和TreeMap)。这项工作还出现在至少8本书和教科书中，包括寄生虫学(Noble等人，1989)、寄生功能生物学(Esch&Amp；Fernandez，1993)和进化论(Ridley，1996)。因此，这项工作已经接触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，墨西哥的合作者和他们的研究生，以及北爱荷华大学(UNI)的本科生，该大学是该项目的分包商。UNI的学生将接受有关寄生虫分类和鉴定、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基本技能的培训，但这些技能正在迅速消失。学生们还将通过路易斯安那州立大学分子实验室为期10天的密集暑期研讨会，接触到拟议研究计划的全部内容。这些研讨会不仅将培训学生与拟议研究相关的分子技术，还将使他们接触到更大的研究实验室的工作原理。这种接触和经验对于鼓励高质量的学生从事非医学基础研究是必不可少的。

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.