Systematics Section / ASPT
Guibert, Cyril , Linder, H. Peter .
Phylogenetic relationships of central European Carex (Cyperaceae) based on nuclear and chloroplastic data.
WITH its 1776 described species, Carex is one of the biggest genera in the Angiosperms. Since the era of phylogenetics based on molecular data the classification concepts of Carex (s.l) have been revised. The major subgenera Eucarex and Vignea from central Europe have been demonstrated monophyletic. Phylogenetic research on Carex has been mainly based on rDNA, which provides many phylogenetic informative characters compared to chloroplastic regions. However, many phylogenetic hypotheses lacked resolution or support, and relationships between the sections could only be roughly estimated. The main objective of this work was to study the phylogenetic relationships of the 20 main central European sections and test the influence of the addition of three chloroplast regions (trnT-L and trnL-F and rpL16) on the phylogeny derived from the commonly used ITS marker. Heuristic parsimony analysis was performed on both regions separately. In subgenus Vignea the trees revealed incongruence between clades based on the rDNA and the plastid phylogenies. We analyse the two histories and discuss the main causes of incongruence (paralogy and hybridisation). We demonstrated that ITS paralogs from monophyletic group for each species that we cloned. Based on the high number of reported hybrids in Carex, we hypothesise that in the subgenus Vignea, incongruence between datasets is due to hybridisation in Vignea and that this blurs straightforward phylogenetic tree reconstruction. On the other hand, incongruence was not detected in subgenus Eucarex, parsimony analysis on combined rDNA and cpDNAdata increased tree resolution and branch supports. Many clade confirm the results of previous analyses. Some unexpected relationships are established (i.e section Atratae falls within Digitatae; Albae and Frigidae are early diverged groups of Eucarex). Interpretation of section relationship and evolution hypothesis are provided in view of the new data.
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1 - Universität Zürich, Institut für Systematische Botanik, Zollikerstrasse 107, Zürich, CH-8008, Schweiz
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 2:00 PM