用核糖体DNA的ITS序列探讨滇桐属的系统学位置  

A Reevaluation of the Taxonomic Position of the Genus Craigia Based on the nrDNA ITS Sequence

作　　者：袁长春[1] 施苏华[1] 钟扬[2] 龚洵[1] 

机构地区：[1]中山大学生命科学学院,广东广州510275 [2]复旦大学生命科学学院,上海200433

出　　处：《中山大学学报（自然科学版）》2002年第6期73-77,共5页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家杰出青年基金资助项目 (3982 5 10 4 ) ;国家自然科学基金资助项目 (30 0 70 0 5 3) ;广东省自然科学基金资助项目 (0 0 12 2 3)

摘　　要：采用PCR直接测序方法 ,对来自椴树科、梧桐科、木棉科 17属的 33个种和作为外类群的锦葵科 2属4个种的核糖体DNAITS区 (含 5 8S区 )序列进行了分析。结果表明 ,滇桐属 (Craigia)与椴树属为姐妹群关系 ,二者构成单系类群 ,因而将滇桐属置于椴树科中较为合理 ;刺果藤属和翅子树属有较近的亲缘关系 ,并与蚬木属和柄翅果属构成一个单系类群 ,二者可能与椴树科有更近的亲缘关系 ;榴莲属与椴树科的破布叶属构成单系类群 ;山芝麻属与椴树科、梧桐科和木棉科构成并系关系 ;因此 ,这些属的系统位置尚需进一步确定。综合分析的结果支持将椴树科、梧桐科和木棉科归并到锦葵科中的观点。There are various arguments on the taxonomic position of the genus Craigia Smith et Evans. In the present paper, 33 species representing 17 genera of the Tiliaceae, Sterculiaceae and Bombacaceae and 4 outgroup species from Mavlaceae were used to analyze the molecular phylogeny of the genus Craigia using sequence analysis of the internal transcribed spacers (ITS) and 5 8S rRNA gene of nuclear ribosomal DNA. Direct PCR sequencing method was used in the study. The most parsimonious trees were obtained by PAUP analysis with heuristic search. In the trees, the Craigia yunnanens is basal to a monophyletic group comprising Tilia pauciostata, T. hupeiensis, T. platyphyllos, T. tomentosa and T.heterophylla (bootstrap value=100). Therefore, it is reasonable to classify the genus Craigia into the Tiliaceae. There is a relatively close relationship between Pterospermum heterophyllum and Byttneria urticifolia, and the both become basal to the monophyletic group comprising Burretiodendron esquirolii and Excentrodentron hsienmu (bootstrap value=81). The same thing occured between the genus Durio(Bombacaceae) and Microcos paniculata (Tiliaceae). As to the status of the genus Helicteres is still undeterminated, there is a parallel relationship among it and Bombacaceae, Sterculiaceae and Tiliaceae. Since the three families Bombacaceae, Sterculiaceae and Tiliaceae are shown to be \{polyphyletic,\} further studies on their phylogenetic relationships are necessary.

关 键 词：核糖体DNA ITS序列 系统学位置 系统发育 姐妹群 滇桐属 梧桐科 PCR直接测序法 亲缘关系 

分 类 号：Q949.757.5[生物学—植物学]