Forensic Science Program, Department of Applied Science, Faculty of Science, Prince of Songkla University, 15 Karnjanavanich Road, Kho Hong, Hat Yai, Songkhla, 90110, Thailand.
College of Science and Engineering, Flinders University, Adelaide, SA, 5042, Australia.
Int J Legal Med. 2021 Jan;135(1):107-115. doi: 10.1007/s00414-020-02414-w. Epub 2020 Sep 25.
Elephant populations have greatly reduced mainly due to illegal poaching for their ivory. The trade in elephant products is protected by national laws and CITES agreements to prevent them from further decline. For instance, in Thailand, it is illegal to trade ivory from African elephants; however, the law allows possession of ivory from Asian elephants if permission has been obtained from the authorities. As such, means of enforcement of legislation are needed to classify the legal status of seized ivory products. Many DNA-based techniques have been previously reported for this purpose, although all have a limit of detection not suitable for extremely degraded samples.
We report an assay based on nested PCR followed by DGGE to confirm the legal or illegal status of seized ivory samples where it is assumed that the DNA will be highly degraded.
The assay was tested on aged ivory from which the assay was tested for reproducibility, specificity, and, importantly, sensitivity. Blind testing showed 100% identification accuracy. Correct assignment in all 304 samples tested was achieved including confirmation of the legal status of 227 highly degraded, aged ivories, thus underlining the high sensitivity of the assay.
The research output will be beneficial to analyze ivory casework samples in wildlife forensic laboratories.
由于非法偷猎象牙，大象数量大幅减少。为了防止大象进一步减少，国家法律和《濒危野生动植物种国际贸易公约》保护大象产品的贸易。例如，在泰国，交易来自非洲象的象牙是违法的；然而，如果从当局获得许可，法律允许拥有来自亚洲象的象牙。因此，需要执法手段来对查获的象牙制品的法律地位进行分类。为此，已经有许多基于 DNA 的技术被报道，尽管所有技术的检测限都不适合极降解的样本。
我们报告了一种基于巢式 PCR 后 DGGE 的检测方法，以确认查获的象牙样本的合法或非法地位，因为这些象牙样本的 DNA 高度降解。
该方法在陈旧象牙上进行了测试，以检验其重现性、特异性，重要的是，敏感性。盲测显示 100%的识别准确率。在 304 个测试样本中，所有样本都得到了正确的鉴定，包括对 227 个高度降解的陈旧象牙的合法地位的确认，从而突出了该检测方法的高灵敏度。
研究结果将有助于在野生动物法庭实验室分析象牙案件样本。
