Nucleotide Signature and SNP Double Peak Methods Detect Adulterants and Substitution in Panax Products

Abstract

There is a big international market for medicinal Panax medicines and their products, such as Panax ginseng, Panax quinquefolium, Panax notoginseng and so on. Panax species share similar morphological characteristics, however possess obvious difference in pharmacological effects and price. Thus, the adulterants are of widespread in ginseng market. Commonly used identification methods, morphological identification and chemistry analysis for example, are sometimes neither efficient nor accurate dealing with ginseng adulterations. DNA barcoding and mini-barcoding technique give us new insights into identification of ginseng materials and products. DNA barcoding technique could succeed in distinguishing species by obvious differentials between interspecific distances and intraspecific distances, however fail in distinguishing closely related species among which the difference between interspecific distances and intraspecific distances is ambiguous. According to the alignment of all available DNA barcoding sequences of Panax species, the species-specific SNPs are excavated and then nucleotide signature method and double-peak detection method are established based on the species-specific SNPs. Nucleotide signature of Panax ginseng, Panax quinquefolium and Panax notoginseng has been exploited. The nucleotide signature combined with double-peak detection method or NJ tree analysis could accurately identify closely related Panax species and deal with the DNA degradation occurred in ginseng products with high efficiency.