DISSERTATION RESEARCH: An Investigation of the Role of Interaction between Muller's Ratchet and the Red Queen in the Maintenance of Sex in a Freshwater Snail

Indiana University, Bloomington IN

Investigators

Abstract

Abstract DISSERTATION RESEARCH: An Investigation of the Role of Interaction between Muller's Ratchet and the Red Queen in the Maintenance of Sex in a Freshwater Snail Lively DEB-0308382 Despite the two-fold reproductive advantage of asexual over sexual reproduction, most eukaryotic taxa are sexual. Although there are several mechanisms that can theoretically maintain sex, all require assumptions that limit their applicability. Recent theory has shown that interaction between mutation accumulation and parasite pressure can maintain sex under less restrictive conditions than under either mechanism acting alone. More specifically, the bottlenecking of asexual lineages caused by virulent parasitism will increase the strength of genetic drift and thus the rates of deleterious mutation accumulation and lineage extinction in heavily parasitized lineages relative to less parasitized lineages. The proposed study will examine these predictions by using mitochondrial DNA sequence information to estimate the age of and mutational distribution within asexual lineages from mixed sexual/asexual populations of a freshwater snail that are afflicted by varying frequencies of infection by a castrating trematode. The results of this project, the first known to address whether interaction between mechanisms can maintain sex in nature, will be a valuable contribution to the debate surrounding the mechanisms underlying the maintenance of sex. The results would be of wide interest to evolutionary and conservation biologists.