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

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Hybridization, introgression (movement of genes from one species into anothervia hybridization), and polyploidization (chromosome doubling) are importantphenomena in plant speciation and evolution. A well-resolved genealogical tree,depicting the species relationships, is fundamental to understand these phenomena, butcan be extremely challenging to construct. This research has two aims. The first is todevelop strategies for resolving such genealogical trees. The second is to use thesemethods to untangle the evolutionary history of the Verbena complex, a groupcharacterized by the prevalence of hybridization, introgression, and polyploidization. Bythe comparing sequences of four independent DNA regions from the chloroplast andnuclear genomes, genealogical trees will be constructed to infer relationships. Inaddition, hundreds of transposable elements (SINEs and MITEs), genetic elements thatcan move from one location to another on chromosomes, will be identified and used totrace the evolutionary history of the organisms that host them.Anticipated outcomes include a well-resolved evolutionary tree of the Verbenacomplex, which will be incorporated into an updated taxonomic treatment incollaboration with botanists at the Instituto Darwinion, Argentina. Using transposableelements to trace evolutionary histories is a novel application to plant evolutionarystudies and may have great impact on such studies. Results from this research will bepresented at annual scientific meetings and submitted to peer-reviewed journals forpublication.