Systematics Section / ASPT
Starr, Julian R. , Teoh, View , Roalson, Eric , Muasya, A. Muthama , Simpson, David A. .
Towards a phylogenetic classification of sedges (Cyperaceae): chloroplast (rbcL, matK, ndhF) and nuclear (ADC) data.
THE Cyperaceae are a truly remarkable group characterized by their exceptional diversity (ca. 5000 spp.), varied ecology (tundra to rainforests), unusual cytology (agmatoploidy) and diverse biogeographical patterns (Gondwanaland, Arcto-Tertiary). Ecologically and economically, sedges have a global impact on humanity in both direct (food, construction materials) and indirect (weeds, habitats) terms, and yet relationships within Cyperaceae are poorly known. Chloroplast rbcL sequences have been used since 1993 in six different studies to examine the ordinal, subordinal and subfamilial relationships of Cyperaceae. These phylogenies have suggested many exciting new hypotheses of relationship, but resolution and support has often been poor. With the long-term goal of developing a robust phylogenetic hypothesis to reclassify Cyperaceae, we have developed new chloroplast (matK, ndhF) and nuclear (arginine decarboxylase or ADC) markers. When these regions are combined with rbcL (ILD test, P=0.64) they produce over 1,084 informative characters, or 7.6 times those provided by rbcL alone. Combined analyses of rbcL+matK (2G analysis; 62 taxa) and rbcL+matK+ndhF+ADC (4G analysis; 27 taxa) produced highly resolved and supported trees: 70% and 78% of internal nodes in the strict consensus of 2G and 4G analyses possessed bootstrap values >90%. Notable results not seen or poorly supported in previous analyses include: (1) strong evidence (99% BS, 4G) that Schoenoplectus is separate from Fuireneae and sister to a strongly supported Cypereae (100% BS); (2) Abildgaardieae is monophyletic (94-100% BS; 2G+4G) and sister to Eleocharideae (94% BS); (3) strong evidence for a Dulichieae/Scirpeae I/Cariceae clade (94% BS; 2G) with Scirpus s.s. and Eriophorum sister to Cariceae (90% BS; 2G), and (4) a fully resolved and robustly supported backbone that marks the major clades in Cyperaceae. Analyses suggest that increased taxonomic sampling and the addition of another marker (preferably nuclear) would produce a robust phylogeny for reclassifying the family.
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1 - University of Mississippi, Department of Biology, 214 Shoemaker Hall, University, Mississippi, 38677, USA
2 - Washington State University, School of Biological Sciences, Po Box 644236, Pullman, Washington, 99164-4236, USA
3 - University of Cape Town, Department of Botany, Private Bag, Rondebosch, Western Cape, 7701, South Africa
4 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, United Kingdom
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 11:00 AM