RESUMO
ObjectiveTo identify the molecular biology of various species of Tibetan Codonopsis plants based on internal transcribed spacer（ITS）2 and psbA-trnH sequence barcode technology. MethodThe genomic DNA of 28 Tibetan Codonopsis plant samples from four species （Codonopsis canescens，C. foetens subsp. nervosa，C. pilosula， and C. thalictrifolia var. mollis） were extracted，and the ITS2 and psbA-trnH sequences were amplified and sequenced. The related sequences of 81 Tibetan Codonopsis plant samples belonging to 15 species were downloaded from GenBank， and MEGA 6.0 was used for sequence comparison and mutation site analysis. The GC content and genetic distance within and between species were calculated. Additionally， phylogenetic trees were constructed by maximum likelihood （ML） method， neighbor-joining （NJ） method，and unweighted pair-group method with arithmetic means （UPGMA） . ResultAccording to the mutation site，C. canescens， C. pilosula，C. pilosula subsp. tangshen， C. pilosula var. modesta，C. bhutanica，C. clematidea，C. lanceolata，C. subglobosa and C. foetens were distinguished. In the phylogenetic trees，the optimal clustering effects for ITS2 and psbA-trnH sequences were obtained using the ML method and the UPGMA method， respectively， and 12 species were effectively clustered. ConclusionITS2 and psbA-trnH sequences have a high identification rate for species of single origin，but there are still some limitations in identifying variants and original variants. This study provides basis for the identification of affinity relationship and clinical safety of Tibetan Codonopsis plants.