DISSERTATION RESEARCH: The Effect of Mutation Rate on Mitochondrial Genome Evolution in the Angiosperm Genus Silene

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

A central challenge in the field of molecular evolution is to elucidate the mechanisms that have produced the enormous diversity in genome organization, structure and function that exists across the tree of life. The proposed research will examine the role of mutation rates in differentially shaping genome evolution by comparing the mitochondrial DNA sequence, structure and function for two closely related species of flowering plants (Silene latifolia and Silene noctiflora) that differ more than 100-fold in mitochondrial mutation rates. For each species, the entire mitochondrial genome will be sequenced along with a sample of genes from the chloroplast genome (which does not exhibit any differences in mutation rate between the species), and patterns of RNA editing and intron splicing will be identified by sequencing cDNA. Given the many commonalities between the mitochondrial genomes of flowering plants and the nuclear genomes of multicellular organisms (such as the proliferation of non-coding DNA), the implications of this work will extend to the evolution and function of the nuclear genome. Elucidating the dynamics of mitochondrial mutations is potentially important for understanding a wide variety of mitochondrial pathologies in humans and the mechanistic basis of cytoplasmic male sterility in plants, a phenomenon that is of great importance in agricultural systems. Annotated mitochondrial genome sequences will be of broader value to the Silene research community in diverse fields of study including breeding system evolution, metapopulation genetics, organelle transmission, systematics and molecular evolution. Also, the research will provide a valuable opportunity to train University of Virginia undergraduates in the modern techniques of molecular genetics and bioinformatics.