Lively 9317924 The purpose of this study is to evaluate some of the critical assumptions of the recently developed parasite hypothesis for the maintenance of genetic diversity and cross fertilization in natural populations. The most critical assumption of the parasite hypothesis is that there is selection imposed by parasites against host genotypes that become locally common. If this idea is correct, then there will be a disadvantage to clonal reproduction that is proportional to the frequency of any clonally produced type. Such selection requires that there is a genetic basis to infection by parasites, and that parasites rapidly "track" locally common host genotypes. An ideal system for testing these ideas is the snail-parasite interaction that Dr. Lively has been working on since 1985. The snail and its parasite ( a trematode worm) can be easily reared in the laboratory. The goal of the study is to determine whether the parasite rapidly evolves to infect different clonal types, and whether it can prevent clones from competitively displacing cross-fertilizing forms. The results will be of interest to evolutionary and conservation biologists interested in the maintenance of genetic diversity, as well as epidemiologists working on similar parasites that cause human disease(e.g. Schistosomiasis).
