目的：对药材桃仁及其近缘种进行ITS2 分子鉴定，以保证药材质量及用药安全。方法：利用DNA 条形码技术，对桃仁及其近缘种的ITS2 核基因片段进行扩增并双向测序，经CodonCode Aligner V4.1 拼接后，将所有的ITS2 序列用MEGA5. 0 软件进行相关数据分析，并构建NJ 树。结果：桃仁两基原物种ITS2 序列长度为212~213 bp，序列变异较小；两基原物种ITS2 序列与近缘种的种间平均K2P 遗传距离大于其种内平均K2P 遗传距离；由NJ 树可知，桃仁的两基原物种聚为一枝，并与其他近缘种明显分开。结论：ITS2 序列作为DNA 条形码可以有效地鉴定药材桃仁及其近缘种，为其他中药及其近缘种的鉴定提供一定的参考依据。

Objective: To identify Persicae Semen and its sibling species, and to secure the quality and clinical safety of this medicinal material. Methods: The internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA of Persicae Semen and its sibling species were amplified and bidirectionally sequenced by DNA barcoding. Sequence assembly and consensus sequence generation were performed by the CodonCode Aligner 4.1. The genetic distances were computed by MEGA 5.0 in accordance with the Kimura 2-parameter (K2P) model, and the phylogenetic tree constructed by the neighbor-joining (NJ) method. Results: The length of ITS2 sequences of the two origin plants of Persicae Semen was between 212 bp to 213 bp. Their intraspecific genetic distance was much lower than the interspecific genetic distance with their sibling species. The ITS2 sequence possessed the character of good stability and low intra-specific sequence variation. In the NJ tree, both Prunus persica and P. davidiana were clustered into one large branch, and clearly separated with their sibling species. Conclusion: ITS2 can be used to effectively distinguish Persicae Semen from its sibling species, which can provide a reference for the identification of other Chinese medicine and its sibling species.

财政部教育部中央高校基本科研业务费专项（2012-郁-107）：青年教师探索项目，负责人：刘霞。