Eric J. Tepe
Postdoctoral Research Associate
Department of Biology
phone: 801 585-0420
In my research into plant systematics I make use of both traditional and contemporary techniques to study evolutionary relationships among species, morphological evolution, and the diversification of plant groups in both space and time. In the Bohs lab at the University of Utah, I am working on the taxonomy and evolutionary relationships of the giant genus Solanum. With over 1000 species, the genus Solanum presents the opportunity to work on both large and small-scale questions within the same group of plants. Weese & Bohs 2007 recovered 12-15 well-supported major clades within Solanum. The informally named “Potato Clade” is one of these, and since it includes the potato (S. tuberosum), tomato (S. lycopersicum), and pepino (S. muricatum), it is one of the most economically important clades of plants in the world. The potato clade is exclusively New World in distribution, with most groups centered in the Andes of South America.
Relationships within the Potato Clade
Most of the 200-300 species in the potato clade belong to a group of species closely related to tomato and potato and, as a result, are the focus of intense research; however, the clade contains four other smaller groups that remain virtually unknown and relationships among all of these groups are poorly understood. The purpose of this study is to use DNA sequences from the nuclear and chloroplast genomes to resolve relationships among the groups that make up the potato clade and to identify morphological traits that make each of the groups easily identifiable in the field.
This study is in its preliminary stages, but the potato clade consists of five major groups: section Anarrhichomenum; section Basarthrum; section Herpystichum; and section Pteroidea; and a strongly supported clade composed of sections Petota (containing the potato), Lycopersicon (containing the tomato), Lycopersicioides, Juglandifolium, and Etuberosum.
Revision of Solanum section Herpystichum
Despite the intense research focused on potato and its close relatives, other parts of the "potato clade" are very poorly known. I am currently working on a revision of Solanum section Herpystichum, one of the most poorly known and undercollected of these groups. The section consists of viny plants that root at the nodes, some of which are emergent aquatics. This research has resulted in the discovery of a new species of Solanum from eastern Ecuador.