利用12S rRNA基因标记鉴定鱼翅真伪

为检测鱼翅样本真伪及鲨鱼种属,通过提取送检鱼翅、鱼翅羹样本DNA,扩增其线粒体DNA上的用于动物种属鉴定的12S rRNA基因片段,并进行DNA测序和序列分析,测序结果在GenBank上进行BLAST搜索,与数据库中相关物种序列进行同源性分析。结果表明,在送检的23份样本中,18份鱼翅羹样本、2份粉丝状鱼翅、1份翅状鱼翅中均未成功提取到DNA,未扩增出目的基因片段,而从2份鱼翅样本中成功地提取到了基因组总DNA,并成功扩增出了12S rRNA基因片段,这2份样本的12S rRNA基因片段的碱基序列分别与黑边鳍真鲨(Carcharhinus limbatus)、斜锯牙鲨(Rhizoprionodon terraenovae)的同源性达到99%。对鉴定出含有鲨鱼成分的2份样本进行高温泡发处理,高温泡发实验表明,1份样本(22号)有明胶析出。研究证实,12SrRNA基因序列测定技术能准确、快速鉴定待检样本中是否含有鲨鱼成分,结合高温泡发时是否有明胶析出可综合判定鱼翅真伪。

Identification of Shark Fin Using 12S rRNA Gene Marker

To detect authenticity and species of 23 suspected shark fin samples. DNAs from either shark fin or shark fin derived soup were extracted, and then 12S rRNA gene of mitochondrial DNA that was special for animal species identification was amplified. PCR product was sequenced and homology comparison was deployed by BLAST search in GenBank database with related species sequences. The results showed that, among a total of 23 suspected shark fin samples, 18 soup-sourced, two vermicelli-like, and a fin-like one were failed to extract DNA or amplify target fragments, while the remaining two samples were successful to extract genome DNA and amplify the corresponding 12S rRNA gene fragments. Sequence analysis indicated nucleotide sequences of the 12S rRNA gene fragment from the two samples matched 99% identity to Carcharhinus limbatus and Rhizoprionodon terraenovae, respectively. For those samples containing shark components, high temperature soaking treatment was carried out. High temperature soaking treatment showed gelatin was precipitated in a sample (22#).These results indicated 12S rRNA gene sequence determination could accurately and quickly identify whether the samples contained shark ingredients. If combined with the high temperature soaking treatment to observe whether there was a gelatin precipitation, we can comprehensively judge the authenticity of shark''s fin.