利用DNA条形码技术鉴定一批鳄鱼产品

Identification of Crocodile Production Through DNA Barcode

DNA条形码技术现已广泛应用于物种鉴定及分类研究。采用该技术对海关查获的一批走私鳄鱼产品进行鉴定,从该批鳄鱼产品中抽取3类样品(鳄鱼肉干、鳄鱼鞭及鳄鱼皮干)各1份,提取样品中的线粒体DNA,并使用通用引物扩增各样品的COⅠ基因部分序列,将扩增到的序列与GenBank中下载的5种鳄鱼的18条同源序列进行比对分析,并利用MEGA4.0计算物种间的遗传距离,发现3种未知样品与暹罗鳄(Crocodylus siamensis)的序列相似性最高,达到99.6%-100%,遗传距离最小,为0.000-0.003。以孟加拉巨蜥(Varanus bengalensis)作为外群,采用P-distance等模型,构建NJ树,结果 3类样品均与暹罗鳄聚为一枝。上述结果分析表明,3类未知样品均来自暹罗鳄,该结果也为海关人员执法提供了依据。

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 ofCrocodylus siamensis.The genetic distance that was computed by MEGA4.0 between thoses samples andCrocodylus siamensiswas 0.000-0.003,which was the minimum.The phylogenetic tree were constructed by P-distance model and Neighbor-joining method,andVaranus bengalensiswas set as the outgroup.The result indicated that all of the three samples come fromCrocodylus siamensis.Consequently,it convincingly demonstrated that the samples were Crocodylus siamensis products,which provides a powerful evidence for the execution of the customs.