Identification of the original species of cubilose based on DNA barcode

Cubilose, a valuable traditional Chinese medicine, is mainly composed of the saliva by several species of Aerodramus or Collocalia in the Apodidae. Due to rarity, high economic value and huge market demand, its fake or adulteration is frequently found in the market. Therefore, it is urgent to establish a simple and accurate method for authenticating cubilose. DNA barcoding, which is an easy, quick and reliable method, is widely used to trace the origin of traditional Chinese medicine. For identifying the original species of cubilose, cytb gene of 18 cubilose samples including 15 officer cubilose and 3 feather cubilose were amplified and entered into the GenBank database using the BLAST search tool. The genetic distances among 18 cubilose samples were calculated based on the Kimura two parameter (K2P) model. To construct the reference database, 18 cytb sequences of Aerodramus or Collocalia were downloaded from GenBank. The neighbor-joining (NJ) and unweighted pair group method with arithmetic average (UPGMA) trees were constructed based on sequences from GenBank and our dataset. Blast analysis showed that all cubilose samples had the highest similarity with A. fuciphagus, and the sequence similarity reached over 99%. Genetic distance of 18 cubilose samples ranged from 0.000-0.010. Trees constructed by NJ and UPGMA gave similar topology: all cubilose samples clustered together with A. fuciphagus. These result demonstrated that the original species of all 18 cubilose samples were A. fuciphagus, and cytb gene is a good candidate for identifying cubilose.