DNA barcoding in concentrated Chinese medicine granules using adaptor ligation-mediated polymerase chain reaction

The use of DNA barcodes for species identification is a common laboratory practice. However, PCR amplification of full-length DNA barcode in processed material is difficult because of severe DNA fragmentation. In this study, an adaptor ligation-mediated PCR protocol was derived to amplify sets of target DNA fragments isolated from two CCMG products. The specially designed adaptor with asymmetric strands and terminal modification avoids amplification of non-target DNA sequences. DNA extracted from Angelica sinensis and Panax notoginseng CCMG were ligated with the adaptors and amplified by an adaptor primer and a single universal barcode primer to obtain partial ITS2 sequence. Results showed that various length of DNA fragments within the ITS2 region were amplified and could be used to identify the concerned species. The adaptor ligation-mediated PCR is therefore a promising universal method for species identification in highly processed herbal products.