目的 通过测定和分析15种悬钩子属Rubus L. 药用植物的rDNA ITS序列，为分子鉴定和遗传多样性研究奠定基础。方法 以叶片基因组DNA和通用引物为材料，用PCR法克隆rDNA ITS全长，并利用生物信息学软件对序列进行分析。结果 15种悬钩子属植物ITS1、ITS2和5.8 S的序列长度分别为255～258、208～211和164 bp；ITS1和ITS2序列有变异位点138个，其中信息位点41个，序列存在较多的颠换、转换和缺失现象；5.8 S序列较为保守，仅含4个变异位点，没有发现信息位点；15种悬钩子属植物的遗传距离为0.139 0～0.008 1，灰毛泡和锈毛莓的遗传距离最小。结论 获得了15种悬钩子属药用植物的rDNA ITS序列，为分子鉴定和遗传多样性研究奠定了基础。

Objective Cloning of Actin gene from Paeonia lactiflora and expression analysis of Actin gene with RT-PCR technique. Methods Based on cDNA sequences of Actin genes isolated from the related species reported in GenBank, one pair of PCR primers was designed. PCR products of Actin gene were successfully amplified with RT-PCR technique using cDNA synthesized from the total RNA extracted from the roots of P. lactiflora ‘Taohuafeixue’ as template, and then they were cloned to pMD18-T vector with TA cloning method. The positive clones which were characterized with colony PCR, plasmid PCR, and enzyme digestion method were sequenced. Based on the sequencing results, one pair of PCR primers was designed, and the expression profile of Actin gene in the roots, stems, flowers, and leaves in P. lactiflora were semi-quantified with RT-PCR technique. Results The sequencing results showed that the length of Actin gene of P. lactiflora was 1 134 bp, encoding 377 amino acids, whose GenBank accession number was JX310002. Sequence analysis showed that Actin of P. lactiflora contained three kinds of characteristic signal sequences, whose homologous similarity in amino acid level with other plants was up to 99%. Based on homology modeling analysis, it revealed that there were four domains in its 3D structure. Bioinformatic software predicted that the molecular weight of Actin of herbaceous peony was 4.17 × 10⁴, and the isoelectric point (pI) was 5.31. It was a hydrophilic and stable protein which was located in cytoplasm, without the transmembrane domain or signal peptide. Semi-quantitative RT-PCR analysis showed that the gene expression levels of Actin gene in the roots, stems, flowers, and leaves of P. lactiflora were almost constant. Conclusion It is the first report on the cloning of Actin gene from P. lactiflora and the semi-quantitative analysis indicates that Actin gene can be used as the internal standard gene for the expression analysis of functional genes in P. lactiflora. This project plays a base for the effective application of Actin gene in P. lactiflora.