ABSTRACT
ObjectiveThe internal transcribed spacer （ITS） 2 region of ribosomal gene， a DNA barcode， was employed to identify 12 medicinal Aconitum species and the genetic relationship among the species was analyzed. MethodA total of 30 samples of the 12 species were collected. The DNA was extracted with spin column plant genomic DNA kit and the universal primers of ITS2 sequence were used for polymerase chain reaction （PCR） amplification， followed by electrophoresis detection and bi-directional sequencing. The yielded sequences were aligned and spliced by CodonCode Aligner 17.0 and sequence variation was analyzed by MEGA 7.0. The secondary structure was predicted by ITS2 Database and the neighbor-joining （NJ） method was applied to generate the phylogenetic tree. ResultThe ITS2 sequences of the 12 species were 220-221 bp， with the average guanine and cytosine （GC） content of 64.09%， 140 variable sites， 137 informative sites， and 81 conservative sites. The intraspecific genetic distance （K2P） was smaller than the interspecific genetic distance. According to the secondary structures of ITS2 sequences and NJ cluster analysis， A. scaposum， A. sinomontanum， and A. barbatum had close genetic relationship， while the rest nine showed close kinship， particularly A. soongaricum and A. yinschanicum. ConclusionITS2 sequence is of great value for the molecular identification and genetic relationship determination of Aconitum， which provides a new method for the study of ethnomedicine.