Phylogeny of the Ranunculaceae based on preliminary atpB, rbcL and 18S nuclear ribosomal DNA sequence data
The chloroplast genes atpB and rbcL and nuclear ribosomal 18S DNA were sequenced for 23 genera of the Ranunculaceae and two outgroup taxa (Hydrastis and Glaucidium). The three sequence data sets were combined and the resulting preliminary phylogenetic tre
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Phylogeny of the Ranunculaceae based on preliminary atpB, rbcL and 188 nuclear ribosomal DNA sequence data SARA B. HOOT Received December 19, 1994
Key words: Ranunculaceae,-atpB, rbcL, nuelear ribosomaI18S DNA, phylogeny. Abstract: The chloroplast genes atpB and rbcL and nuelear ribosomaI 18S DNA were sequenced for 23 genera of the Ranunculaceae and two outgroup taxa (Hydrastis and Glaucidium). The three sequence data sets were combined and the resulting preliminary phylogenetic tree us ed to assess relationships within the Ranunculaceae. The phylogeny strongly supports the monophyly of the family, with 26 substitutions, a bootstrap value of 98% and a decayindex of> 7. Within the family, the T-type chromosome group is basal and paraphyletic with respeet to the larger R-type chromosome group. Within the T-type chromosome group, Coptis and X anthorhiza from a monophyletic group and are basaI to all other Ranunculaceae. Other alliances previously proposed by taxonomists are confirmed: AnemonellajThalictrumj lsopyrumjAquilegiajSemiaquilegia; AnemonejClematis, Trautvetteriaj M yosurusjRanunculus; AconitumjDelphinium; and AnemonopsisjCimicijugaljActaea. Other groupings that could not have been predicted on the basis oftraditionaI data inelude a elade consisting of Adonis and Trollius and the inelusion of Eranthis in a elade with Anemonopsis, Cimicijuga, and Actaea. Nigella is weakly allied with a elade consisting of Aconitum and Delphinium. The molecular sequence data are largely congruent with results based on cytology, phytochemistry, and micromorphology. Flower and fruit characters are homoplastic in relation to the eladogram based on sequence data. The pattem of relationships based on sequence data supports the view that staminodiajpetaIs and achenes have evolved independently sever al times within the Ranunculaceae.
Homoplasy in the Ranunculaceae has always been a limiting faetor in the formation of a reliable evolutionary hypothesis and taxonomie treatment of the family. Not onlyare there the problems intrinsie to such a large and varied family, but also the probable oeeurrenee ofwidespread paralleI and convergent evolution. This is clearly exemplified in the present symposium volume, where widely differing phylogenetie hypotheses ean be proposed aeeording to individual data sets: e.g., embryology (ENGEL 1995), morphology (LoeoNTE & al. 1995, this volume), and moleeular data (JOHANSSON 1995, KOSUGE & al. 1995, both in this volume). The karyologieal research of LANGLET (1932) and GREGORY (1941) was instrumental to a major reassessment of evolutionary relationships in the Ranunculaceae. U. Jensen et al. (eds.), Systematics and Evolution of the Ranunculiflorae © Springer-Verlag Wien 1995
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This work resulted in the recognition of two major groups according to chromosome type: the large Ranunculus-type (R-type) and the small Thalictrum-type (T-type) groups. Subsequent work based on serology (JENSEN 1968, 1971), phytochemistry (HEGNAUER 1966, 1973, 1990; RUIJGROK 1966), amino acid sequences (GRUND &
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