山豆根是我国常用中药材，对山豆根基原植物及其易混伪品进行DNA分子鉴定研究具有重要意义。本文对5科9属38个物种84份山豆根基原植物及其混伪品样品的ITS2序列进行序列变异分析、K-2p遗传距离比较及NJ系统发育聚类树构建。结果表明所研究山豆根基原植物样品种内ITS2序列无变异，与其同属密切相关物种的ITS2序列变异位点为102个，平均K-2p遗传距离为0.072，与其他混伪品的ITS2序列变异位点为200个，平均K-2p遗传距离为0.594。山豆根基原植物在NJ系统发育聚类树上聚为一支，支持率为98。因此，ITS2作为DNA条形码序列能够有效的区分山豆根基原植物及其混伪品，为山豆根药材及其混伪品的鉴定提供基础。

In order to discriminate Sophorae tonkinensis Radix et Rhizoma original plant and its adulterants, we collected 84 ITS2 sequences of Sophorae tonkinensis Radix et Rhizoma original plant and its adulterants belonging to 38 species from 9 distinct genera of five families and compared the divergence of these sequences. Then, the genetic distances were computed using PAUP 4b10 in accordance with the Kimura 2-Parameter (K2p) model, and the phylogenetic tree was constructed using the neighbor-joining and Kimura 2-parameter methods. The results showed that ITS2 sequences from different Sophorae tonkinensis samples in this study are identical. ITS2 sequences between Sophorae tonkinensis and its closely related species have 102 variant sites and their mean K-2p distance is 0.072. ITS2 sequences between Sophorae tonkinensis and its other adulterant species have 200 variant sites and their mean K-2p distance is 0.594. Therefore, ITS2 can be used to correctly identify Sophorae tonkinensis Radix et Rhizoma original plant and its adulterants.

卫生部卫生行业科研专项（200802043）：药用植物DNA barcoding(条形码)鉴定研究，负责人：陈士林。