以核內的內轉錄區間序列探討台灣馬兜鈴屬之親緣關係

Phylogenetic Relationships of Plants Belonging to the Genus Aristolochia (Aristolochiaceae) of Taiwan Based on Nuclear Internal Transcribed Spacer Sequences

馬兜鈴屬（Aristolochia）隸屬於馬兜鈴科，是重要的傳統中藥。已知台灣地區分布6種馬兜鈴屬植物包括瓜葉馬兜鈴（Aristolochia cucurbitifolia）、異葉馬兜鈴（A. heterophylla）、大葉馬兜鈴（A. kaempferi）、港口馬兜鈴（A. zollingeriana）、蜂窩馬兜鈴（A. foveolata）和台灣馬兜鈴（A. shimadai）。近10年來，植物系統分類學者利用形態特徵、化學組成和核型來建構本屬內種間之分類地位，然而其結果存在一些爭議。本研究以細胞核內轉錄區間（internal transcribed spacer, ITS）序列作為分子遺傳標誌，分析6種馬兜鈴植物ITS序列之間的遺傳差異並重建種間之親緣關係。結果顯示本屬植物之內轉錄區間序列總長度介於661 bp（港口馬兜鈴）-690 bp（台灣馬兜鈴），全段序列G＋C鹼基組成約63.7%。港口馬兜鈴與異葉馬兜鈴間的遺傳距離最高，為0.609；大葉馬兜鈴與台灣馬兜鈴間最近緣，遺傳距離為0.007。以聚類分析法建構之親緣樹狀圖，台灣的馬兜鈴可區分為兩大群，第一群包括港口馬兜鈴和蜂窩馬兜鈴，其餘4種則形成另一系群。 Plants of the genus Aristolochia (Aristolochiaceae) are important Chinese traditional herb-medicines. There are six species that have been described from Taiwan: Aristolochia cucurbitifolia, A. heterophylla, A. kaempferi, A. zollingeriana, A. foveolata and A. shimadai. Their taxonomic status and systematic relationships have been analyzed in the last decade by means of their karyotypes, morphological characters and chemical constituents, but controversies still remained. We analyzed sequence differences in the internal transcribed spacers (ITS) of the six species, and reconstructed their phylogenetic relationships. The ITS sequences varied in lengths between 661 bp for A. zollingeriana and 690 bp for A. shimadai, while their G+C contents occupied approximately 63.7%. Genetic distances ranged 0.007 between A. kaempferi and A. shimadai, and 0.609 between A. zollingeriana and A. heterophylla. The phylogenetic tree reconstructed with the neighbor-joining method revealed that Taiwan s Aristolochia is divided into two groups: A. zollingeriana and A. foveolata as a group (clade) and A. cucurbitifolia, A. heterophylla, A. kaempferi and A. shimadai as another group (clade).