川芎及其近缘物种的ITS2序列分析与鉴别研究

目的：对常用中药川芎及其近缘物种进行分子鉴定，以确保该药材的质量及临床安全用药。方法：采用PCR技术，获得ITS2基因片段，进行双向测序，运用CodonCode Aligner拼接后，用MEGA5．0软件进行相关数据分析，构建NJ树。应用Schuhz等建立的ITS2数据库及其网站预测ITS2二级结构。结果：川芎与其近缘物种ITS2序列间存在明显差异，基于ITS2序列的NJ树及其ITS2二级结构均可以将川芎及其近缘物种区分开。结论：ITS2可有效地鉴别中药川芎及其近缘物种，在中药鉴定中应用前景广阔。

Authentication of Ligusticum sinense cv. Chuanxiong and Its Closely Related Species by Analysis of ITS2 Sequences

Objective：To identify Ligusticum sinense cv. Chuanxiong and its closely related species, and to secure the quality and clinical safety while using this medical material. Methods：The PCR technique was performed to get the ITS2 regions and purified PCR products were sequenced. Sequence assembly and consensus sequence generation were performed using the CodonCode Aligner. To perform a phylogenetic study ,the sequences of the DNA regions were aligned using Clustal W and the genetic distances were computed using MEGA 5.0 in accordance with the Kimura 2- Parameter（K2P） model, and the phylogenetic tree was constructed using the Neighbor-Joining and K2P methods. The ITS2 secondary structure was predicted using the ITS2 database and website founded by Schultz et al. Results：A marked difference was observed in the ITS2 sequences between L. sinense cv. Chuanxiong and its closely related species. NJ tree based on ITS2 sequences and secondary structure of ITS2 can distinguish L. sinense cv. Chuanxiong and its closely related species. Conclusion ： ITS2 can serve as a valuable marker for identifying L. sinense cv. Chuanxiong and its closely related species, and it has a broad application prospect in the identification of traditional Chinese medicines.