关键词: DNA条形码技术, CO, I 基因, 暹罗鳄, 物种鉴定, NJ树

Abstract: DNA barcode has been extensively used in species identification and taxonomical research. In this paper, a batch of smuggled crocodile products was identified using DNA barcode. Three types of the crocodile products（dried crocodile meat, crocodile penis and dried crocodile skin）were selected as the samples for species identification. Mitochondrial DNA was extracted and cytochrome oxidase subunit I gene fragments of each sample was amplified using the universal primers. Alignment analysis with the data of eighteen homologous sequences of five different crocodile species in GenBank revealed that the three unknown samples had the highest sequences similarity, which was 99.6%－100%, with the sequences of Crocodylus siamensis. The genetic distance that was computed by MEGA4.0 between thoses samples and Crocodylus siamensis was 0.000-0.003, which was the minimum. The phylogenetic tree were constructed by P-distance model and Neighbor-joining method, and Varanus bengalensis was set as the outgroup. The result indicated that all of the three samples come from Crocodylus siamensis. Consequently, it convincingly demonstrated that the samples were Crocodylus siamensis products, which provides a powerful evidence for the execution of the customs.