Systematics Section / ASPT
Kron, Kathleen A. , Powell, E. Ann , Bush, Catherine .
Resolving relationships within Ericoideae (Ericaceae) using chloroplast and nuclear DNA sequences..
Species within the clade Ericoideae exhibit a wide range of morphological diversity including leaves that may be deciduous or evergreen, flowers with polypetalous to sympetalous corollas, and fruits that may be capsules or drupes. Previous molecular and morphological studies of evolutionary relationships within Ericoideae have identified five clades (Bejarieae, Rhodoreae, Phyllodoceae, Ericeae, and Empetreae), most of which are strongly supported by bootstrap analysis. However, relationships among these five clades have not yet been resolved. We obtained nucleotide sequences from 49 species representing all major groups within Ericoideae. DNA sequences from the chloroplast genes matK and ndhF were obtained in addition to sequences from nrITS and the region between exon 9 and exon 11 of the nuclear gene granule bound starch synthase (waxy). Individual parsimony analyses of each of these four regions were performed using PAUP 4.0. Resolution was poor in these analyses with low bootstrap scores for those clades that were resolved. Chloroplast sequences were analyzed together, as were nuclear sequences. These separate analyses resulted in more resolution (e.g., some of major groups of Ericoideae found in previous studies were recovered in the chloroplast and in the nuclear analyses). Because there were no conflicting relationships with more than 50% bootstrap support between the two compartments (chloroplast vs. nuclear) all of the data were combined and analyzed simultaneously. Strict consensus of the two most parsimonious trees found indicates that Ericeae are sister to remaining Ericoideae included in the analysis. Phyllodoceae are strongly supported as monophyletic and are sister to Bejaria. Empetreae are sister to Rhodoreae and within Rhodoreae, Menziesia is placed within Rhododendron. These relationships indicate that deciduous leaves and polypetalous corollas are likely derived features within Ericoideae.
1 - Wake Forest University, Department of Biology, P.O. Box 7325, Winston-Salem, North Carolina, 27109-7325, U.S.A.
Presentation Type: Paper
Location: Cottonwood B (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 2:30 PM