Systematics Section / ASPT
Selliah, Sugirthini , Brouillet, Luc .
Molecular phylogeny of the North American eurybioid asters, Oreostemma, Herrickia, Eurybia, and Triniteurybia (Asteraceae, Astereae) using a low copy nuclear gene, CNGC4, a.
The aster genera Oreostemma, Herrickia, Eurybia, and Triniteurybia, collectively called the eurybioid grade, belong to the North American clade of tribe Astereae, at the base of the Machaerantherinae. The taxonomic relationships of the eurybioid grade, based on morphology, has been uncertain. A phylogenetic study based on nuclear ribosomal DNA (ITS and 3’ETS) data was unable to fully resolve phylogenetic relationships within this lineage and showed slight incongruence between the regions. In order to obtain a better understanding of the evolutionary history of the eurybioid grade, more variable markers were needed. Because few rapidly-evolving, low copy nuclear genes have been developed for Asteraceae, we optimised a marker originally charaterized in the Leguminosae, part of the cyclic nucleotide gated channel gene (CNGC4). The region between exons 5 and 7 (on the Arabidopsis sequence) was cloned and sequenced; the exons were easily aligned, but the introns proved very variable and parts had to be excluded. Though less variable than ribosomal or nuclear regions, three chloroplastic regions (combined in analyses) were used to provide data from an independent dataset: trnL-F, trnC-ycf6, and trnS-G. Parsimony and Bayesian analyses were performed on each dataset separately. Results are generally congruent with the ITS-ETS analyses, but resolution was improved in the CNGC4 analysis, despite incomplete lineage sorting. The following relationships appear to be confirmed: Symphyotrichinae (Oreostemma (Herrickia (Eurybia (Triniteurybia (Machaerantherinae))))). The eurybioid grade, a group with x = 9 that inhabits mainly humid to mesic habitats in temperate western and eastern North America, appears to be sister to the more xeric-adapted, southwestern, x= 5 Machaerantherinae.
Log in to add this item to your schedule
1 - Plant Biology Research Institute (IRBV), Biology, 4101 rue Sherbrooke, E, Montreal, Quebec, H1X 2B2, Canada
2 - Plant Biology Research Institute (IRBV), Biology, 4101 rue Sherbrooke, E, Montreal, Quebec,, H1X 2B2, Canada
nuclear and chloroplast DNA analysis.
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM