Molecular Studies of Cospeciation Enhanced by Exhaustive Sampling and GIS Technology

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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.