DISSERTATION RESEARCH: Untangling the Evolutionary History of the Verbena Complex (Verbenaceae): Hybridization, Introgression, and Polyploidization

University Of Washington, Seattle WA

Investigators

Abstract

Hybridization, introgression (movement of genes from one species into another via hybridization), and polyploidization (chromosome doubling) are important phenomena in plant speciation and evolution. A well-resolved genealogical tree, depicting the species relationships, is fundamental to understand these phenomena, but can be extremely challenging to construct. This research has two aims. The first is to develop strategies for resolving such genealogical trees. The second is to use these methods to untangle the evolutionary history of the Verbena complex, a group characterized by the prevalence of hybridization, introgression, and polyploidization. By the comparing sequences of four independent DNA regions from the chloroplast and nuclear genomes, genealogical trees will be constructed to infer relationships. In addition, hundreds of transposable elements (SINEs and MITEs), genetic elements that can move from one location to another on chromosomes, will be identified and used to trace the evolutionary history of the organisms that host them. Anticipated outcomes include a well-resolved evolutionary tree of the Verbena complex, which will be incorporated into an updated taxonomic treatment in collaboration with botanists at the Instituto Darwinion, Argentina. Using transposable elements to trace evolutionary histories is a novel application to plant evolutionary studies and may have great impact on such studies. Results from this research will be presented at annual scientific meetings and submitted to peer-reviewed journals for publication.