- 學位論文
台灣產毛茛科鐵線蓮屬(Clematis L.)植物分子親緣關係之探討
Molecular phylogenetic analysis of Clematis L.(Ranunculaceae) in Taiwan
摘要
毛茛科(Ranunculaceae)鐵線蓮屬植物(Clematis L.)是一泛世界性分佈的類群，約有300種。目前對於鐵線蓮屬之分類研究是將之劃分為7亞屬，而主要分類依據均為外部形態特徵，部分則是解剖學、花粉學的證據。台灣鐵線蓮屬之植物目前紀錄有21個分類群，其中包括16種2亞種3變種，分屬於Campanella、Clematis、Flammula、Tubulosa此4個亞屬。本研究針對葉綠體trnK/matK及nrITS 二基因區域進行PCR並定序，再以核苷酸序列排序，進行譜系分析，期以建立台灣鐵線蓮屬植物的演化樹，並了解其彼此間的親緣關係，並以之和傳統形態分類的結果做比較分析及探討。 除了分類尚不明確的毛果鐵線蓮外，將台灣20個鐵線蓮分類群均取得材料進行分析，並合併GenBank資料庫中32種日本鐵線蓮屬植物(其中有3種台灣亦有產)相同片段的DNA序列進行譜系分析，以毛茛科小白頭翁屬中鵝掌草(Anemone flaccida)作為比對的外群。利用PAUP*4.0b10等軟體進行高度簡約原理(maximum parsimony，MP)、鄰近連接法(neighbor joining，NJ)及貝葉氏導出式分析(Bayesian inference，BI)之譜系分析。結果雖然葉綠體trnK/matK及nrITS二資料矩陣間有顯著差異，但其重要分群組成仍相似。由各種譜系分析的結果歸納出Flammula亞屬位於譜系樹最基群的位置，而其他亞屬間的親緣關係未解，另外，由譜系樹來看，包含種類較多的亞屬Campenalla及Clematis均為側系群。由分子序列和以形態特徵所建構之譜系樹，所得到的親緣關係結果不盡相同，表示現行的鐵線蓮分類仍有再商榷的必要。至於呈現相當大的種內形態變異之串鼻龍(C. grata)中，在靠海邊及靠內陸的植群間，在檢視的二序列中存有些陵t異。因此可能需要更多且變異度更適合的分子序列進行分析，以期得到更完整可信的結果。
並列摘要
The genus Clematis L. (Ranunculaceae) is widely distributed all over the world with about 300 species. They were divided into seven subgenera mainly according to morphologies as well as anatomical and palynological evidence. There are 21 taxa of Clematis recognized in Taiwan, which belong to four subgenera, i.e. Campanella, Clematis, Flammula and Tubulosa. In this thesis I used the sequences of nuclear ribosomal ITS (nrITS) region and chloroplast trnK/matK to infer the phylogenetic relationships among Taiwanese Clematis. The sequences were analyzed separately and in combination, and compared with the phylogeny based on morphological characters. All of the 20 taxa of Clematis in Taiwan were obtained and the sequences were determined successfully, excluding the uncertain species C. uncinata var. okinawensis. The final data set also includes 32 taxa of Clematis in Japan (sequences from GneBank, with three taxa also found in Taiwan). Using Anemone flaccida as outgroup, three separate analysis were employed: maximum parsimony, neighbor joining and Bayesian inference. Partition homogeneity test for trnK/matK and nrITS indicated that these two data sets contain significantly different signals. Nonetheless, since the major grouping between these two data sets are similar, we performed a combined data analysis for inferring phylogeny to access total evidence in that manner. Based on the phylogeny, subgenus Flammula is the basal clade, while the relationships of all the other subgenera are unresolved. Subgenus Campenalla and Clematis are shown to be paraphyletic groups. The phylogenies based on DNA sequences and morphology show certain level of incongruence, suggesting a re-examination at intra-genic level for the genus Clematis. C. grata, the most divergent taxa in terms of its morphology, showed certain degree of populational differentiation based on trnK/matK and nrITS sequence analysis. The populations close to ocean show several nucleotide differences from the inland populations, however a thorough survey is needed to draw unambiguous conclusion.