艾叶及其常见混伪品的分子鉴定

目的：对艾叶及其几种常见混伪品进行分子鉴定。方法：通过聚合酶链式反应（PCR）法直接测序，对艾及其8种混伪品进行核糖体DNA内转录间隔区片段2（ITS2）扩增并双向测序，所得序列经CodonCodeAligner拼接后，用系统发育软件MEGA4．0进行相关数据分析，同时利用邻接（NJ）法构建系统聚类树。结果：艾叶基原植物艾ITS2序列长度为225bp，种内平均Kimura．双参数（K2P）遗传距离（0．000）小于其与混伪品的种间平均K2P遗传距离（0．022）；由所构建的系统聚类树图可以看出，艾具有单系性，同时又与其他混伪品明显分开。结论：ITS2序列作为DNA条形码可以方便快捷地鉴别中药材艾叶及其混伪品，可为其质量评价及临床安全用药提供重要的分子鉴别依据。

Molecular Identification ofArtemisia argyi and Its Adulterants

OBJECTIVE： To identify the molecule of Artemisia argyi and its adulterants. METHODS： The second internal tran- scribed spacer （ITS2） of ribosomal DNA were amplified and sequenced by direct sequencing of PCR products. Sequence assembly and consensus sequence generation were performed by using the CodonCode Aligner. Phylogenetic study was performed by using MEGA 4.0 software, meanwhile the phylogenetic tree was constructed by using the neighbor-joining （NJ） methods. RESULTS： The length of ITS2 sequence ofA. argyi was 225 bp. Its mean intraspecific genetic distance （K2P distance, 0.000） was lower than that （0.022） of adulterants. In the cluster dendrogram,A, argyi showed monophyletic, and meanwhile, distinguished from their adul- terants. CONCLUSIONS： ITS2 sequence can be used as DNA barcode to identify A. argyi and its adulterants effectively, and then provide important molecular evidence for quality evaluation and the safety of drug use in the clinic.