A preliminary investigation on the phylogeny of Saussurea (Asteraceae : Cardueae) based on chloroplast DNA trn L-F sequences

	A preliminary investigation on the phylogeny of Saussurea (Asteraceae : Cardueae) based on chloroplast DNA trn L-F sequences
	Wang Yu-Jin ; Liu Jian-Quan
刊名	ACTA PHYTOTAXONOMICA SINICA
	2004-03-01
英文摘要	Saussurea DC., a highly diversified genus with about 400 species in the Asteraceae, has been an extremely difficult group in both taxonomical and phylogenetic studies. The monophyletic origin, infrageneric classification and systematic positions of some species with unique gross morphology remain unclear for this genus. The main aim of this study was to examine infrageneric relationships of Saussurea as inferred from molecular evidence against the existing supraspecific classification on the basis of the morphological characteristics. In addition, we intended to use phylogenetic analyses of DNA sequence data to investigate systematic position and relationship of each species in sect. Pseudoeriocoryne (subgen. Eriocoryne) and test the monophyly of this section, which is likely to be established based on the morphological characters with convergent evolution. We sequenced chloroplast DNA tmL-F for all four species of sect. Pseudoeriocoryne and other 33 species, which represent the recognized five subgenera in Saussurea, and conducted a phylogenetic analysis together with 14 related genera in the Cardueae Cass. The variation of trnL-F sequences is very low among the sampled species in spite of their extremely diverse morphology. Five subgenera in Saussurea delimitated based on morphological characters were unrecognized on all most parsimonious trees. Sect. Pseudoeriocoryne is a polyphyletic group, and the four species in this section were found to be distantly related to each another, and showed no close relationship with the other species in subgen. Eriocoryne. The morphological characters to circumscribe this section had separately evolved four times. An 18-bp insertion was identified for S. polycolea var. acutisquama in sect. Pseudoamphilaena of the subgen. Amphdaena and other four species, S. hieracioides, S. superba, S. tatsienensis and S. katochaete from the subgen. Saussurea. This long and unique insertion was only recognized for these five species in the total Cardueae, and it must have evolved before the morphological diversification of this species complex. However, this insertion was not found in S. polycolea and another population of S. katochaete. Therefore, the insertion found in S. polycolea var. acutisquama and S. katochaete might have resulted from haplotype introgression or retaining because of hybridization. This study demonstrates for the first time that species even within a genus had also undergone convergent evolution in their morphology under the same ecological selection pressure of the Qinghai-Tibet and habitats. This implication is especially important for those researches, which study relationships of the species distributed there and name taxonomical entities based exclusively on the gross morphology. In addition, our preliminary results indicate that Saussurea provides a typical case for studying rapid speciation, reticulate and convergent evolution under the arid habitats.
内容类型	期刊论文
源URL	[http://ir.nwipb.ac.cn/handle/363003/6843]
专题	西北高原生物研究所_中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Wang Yu-Jin,Liu Jian-Quan. A preliminary investigation on the phylogeny of Saussurea (Asteraceae : Cardueae) based on chloroplast DNA trn L-F sequences[J]. ACTA PHYTOTAXONOMICA SINICA,2004.
APA	Wang Yu-Jin,&Liu Jian-Quan.(2004).A preliminary investigation on the phylogeny of Saussurea (Asteraceae : Cardueae) based on chloroplast DNA trn L-F sequences.ACTA PHYTOTAXONOMICA SINICA.
MLA	Wang Yu-Jin,et al."A preliminary investigation on the phylogeny of Saussurea (Asteraceae : Cardueae) based on chloroplast DNA trn L-F sequences".ACTA PHYTOTAXONOMICA SINICA (2004).