@ARTICLE{TreeBASE2Ref17622, author = {Julian R. Starr and Genevi?ve Gravel and Anne Bruneau and A. Muthama Muasya}, title = {Phylogenetic Implications of a Unique 5.8S nrDNA Insertion in Cyperaceae. Monocots III/Grasses IV}, year = {2007}, keywords = {}, doi = {}, url = {}, pmid = {}, journal = {Aliso}, volume = {23}, number = {}, pages = {84--98}, abstract = {The purpose of this study was to assess the phylogenetic utility of a large insertion (3 bp) in the 5.8S gene of nuclear ribosomal DNA (rDNA) in the Cyperaceae and selected Juncaceae. This was done by reconstructing the character evolution of the insertion on a phylogeny derived from rbcL sequences. Results suggest that the insertion was gained once at the base of the Cyperaceae followed by multiple losses in its most derived taxa. Despite several homoplastic loses (CI = 0.20), the pattern of insertion loss (RI = 0.88) and base pair variation within the insertion were useful for defining sedge clades at various taxonomic levels. For example, whereas an indel loss appeared to characterise a major terminal clade within the Cyperaceae, both insertion losses and sequence variation were consistent with infrageneric clades previously discovered in an ITS phylogeny of the genus Eleocharis. The presence/absence of the insertion also supported previous conclusions based on morphological and molecular data that the tribe Scirpeae and the genus Scirpus s.l. are polyphyletic. In the context of our current understanding of Cyperaceae relationships, evolutionary patterns related to this insertion provide additional support for groups defined in prior phylogenetic analyses. Differences between maximum likelihood and parsimony analyses indicated that the paraphyly of Juncaceae and Cyperaceae, as detected in previous molecular analyses, is based upon a chimeric rbcL sequence for the controversial genus Oxychloe (Juncaceae). When the Cyperaceae portion of the molecule is removed, Juncaceae and Cyperaceae are monophyletic, with Oxychloe positioned within a Southern Hemisphere clade of single-flowered genera in the Juncaceae. Keywords: Cyperaceae, 5.8S insertion, ITS region, Juncaceae, Oxychloe, rDNA.} }

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