Systematics Section / ASPT
Peirson, J. A. , Cantino, P. D. , Ballard, H. E. .
Phylogeny of Collinsonia and Tribe Elsholtzieae (Lamiaceae) Based on ITS Sequence Analysis.
Recent monographic work on the genus Collinsonia (Lamiaceae) has prompted this investigation of evolutionary relationships within Collinsonia and between it and the other five genera of the tribe Elsholtzieae: Elsholtzia, Keiskea, Mosla, Perilla and Perillula. Some authors have recognized another genus, Micheliella, which consists of the four-stamen species of Collinsonia. Recently, Collinsonia and Keiskea have been merged under Collinsonia. To examine the phylogenetic relationships within Collinsonia, and between Collinsonia and the other genera of the tribe Elsholtzieae, the complete Internal Transcribed Spacer (ITS) region of nuclear ribosomal DNA was sequenced for all taxa of Collinsonia and one representative each of Elsholtzia, Keiskea, Perilla and the outgroup Plectranthus. Parsimony and maximum likelihood analyses were performed. Phylogenetic relationships within Collinsonia were not resolved using ITS sequence data due to low levels of sequence divergence (0.7%) across the entire ITS region. However, support for Collinsonia as a clade was very high (100% bootstrap support). Keiskea and Perilla formed a well-supported clade (96% bootstrap support), as did Keiskea, Perilla and Collinsonia (92% bootstrap support). Esholtzia was shown to be sister to the other examined genera of the tribe Elsholtzieae. Parsimony and maximum likelihood analyses recovered identical intergeneric relationships. Keiskea was demonstrated to be sister to Perilla rather than to Collinsonia and thus should not be merged with Collinsonia. The recognition of the genus Micheliella was not supported by the molecular analysis. Future work includes additional taxon sampling within tribe Elsholtzieae and analysis of sequence data from other genomic regions to resolve relationships within Collinsonia.
1 - Ohio University, Department of Environmental and Plant Biology, Porter Hall, Richland Avenue, Athens, Ohio, 45701-2979, USA
2 - University of Michigan, Department of Ecology and Evolutionary Biology, Ann Arbor, Michigan, 48109-1048, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM