Date of Award
Ecologists and evolutionary biologists have long recognized that species diversity is unequally distributed among angiosperm lineages. For example, various plant clades found in the Andes have been proposed as examples of rapid radiations, and the Andes are recognized as one of the Earth’s biodiversity “hotspots”. Species within Valerianaceae, found in the South American Andes, appear to be an example of such a rapid radiation. Although much attention has been paid to the phylogeny of the South American species of Valerianaceae, there is still a great deal of uncertainty regarding species relationships. Several subgroups within the Andean Valerians have, either not been included, or poorly sampled in previous phylogenetic analyses. One example of such a group is section Porteria. Knowing the phylogenetic placement of this group would go a long way in our understanding of Andean biogeography, as well as morphological and floral evolution in Valerianaceae. In this study, I increase the sample size of section Porteria beyond what has been previously done. A number of genomic regions were amplified and sequenced for 6 species belonging to the section. Sequences were then aligned to previously published sequence data for homologous regions for other species in Valerianaceae. A “supermatrix” of 146 species was then analyzed using maximum parsimony. Resulting trees recovered a monophyletic section Porteria, however statistical support was weak for this conclusion. Although “supertrees” resulting from the analysis of “supermatrices” may be powerful tools for testing hypotheses concerning the evolution of species, there is still much work to be done on Valerianaceae.
LeBourgeois, Taylor, "Understanding the Historical Diversification of Valerianacea" (2016). Senior Honors Theses. 78.