Systematics Section / ASPT
O'Leary, T. Ryan , Archibald, Jenny K. , Mort, Mark E. .
A methodological study of the utility of ISSR data for phylogeny reconstruction in populations of the South African species Crassula vaginata (Crassulaceae).
Hypervariable markers (e.g., AFLP, ISSR, etc) have become a popular tool for lower level phylogenetic studies when traditional morphological and sequence based methods fail. Multiple methods of analysis have been proposed on theoretical grounds, but few studies have compared the results of these methods. Crassula vaginata (Crassulaceae) is a succulent, herbaceous plant species that is widespread in the mid-elevation grasslands of southern Africa. The level of molecular divergence in the DNA regions typically employed for lower level studies (e.g., cpDNA spacers and nrDNA ITS) between populations is low and so this species provides an ideal opportunity for testing the use of hypervariable markers for phylogeny reconstruction. Fourteen populations from three regions of South Africa and Lesotho were sampled. Inter-Simple Sequence Repeat (ISSR) data were generating using automated techniques and these data were analyzed using a variety of methods, including one distance-based method and three parsimony methods. Among the three parsimony methods, Fitch parsimony provided resolution that most closely reflected both population and regional cohesion among individuals, and was also the most consistent with estimate inferred from distance methods. Dollo parsimony analysis resulted in clustering of individuals into populations, but exhibited greater mixing of populations from different regions than the Fitch or distance methods. Camin-Sokal parsimony analysis resulted in the least population cohesion and failed to resolve the ingroup as monophyletic, indicating that it is a less desireable approach to analyzing hypervariable markers. We conclude that the distance and Fitch parsimony methods are the most appropriate for phylogenetic inference of ISSR data in C. vaginata.
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1 - University of Kansas, Ecology and Evolutionary Biology, c/o Mark Mort, 1200 Sunnyside Ave, Lawrence, Kansas, 66045, USA
2 - University of Kansas, Department of Ecology and Evolutionary Biology and the Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045, USA
3 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Continental C/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:00 AM