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Discrimination of highly degraded, aged Asian and African elephant ivory using denaturing gradient gel electrophoresis (DGGE)

Abstract

Background

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.

Aim

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.

Method and results

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.

Conclusion and recommendation

The research output will be beneficial to analyze ivory casework samples in wildlife forensic laboratories.

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Availability of data and material (data transparency)

Data are available upon request. Main data are photographs of DGGE gels and agarose gels.

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Acknowledgments

We appreciate the DNP Wildlife Forensic Science Unit, Department of National Parks, Wildlife and Plant Conservation, Thailand for vouchers and unknown samples.

Funding

This work was supported by the Faculty of Science Research Fund, Prince of Songkla University (contract no. 1-2561-02-010), given to NS.

Author information

Affiliations

Authors

Contributions

NS: investigation, methodology, visualization, writing original draft; PT: formal analysis, supervision, writing original draft, writing review, and editing; AL: writing original draft, writing review, and editing; TK: conceptualization, funding acquisition, investigation, methodology, project administration, supervision, writing original draft, writing review, and editing

Corresponding author

Correspondence to Thitika Kitpipit.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All ivory samples were provided the DNP Wildlife Forensic Science Unit, Department of National Parks, Wildlife and Plant Conservation from seizures and thus no consent is applicable. Museum samples were collected by the DNP Wildlife Forensic Science Unit and given to us with permission from the museums. Blood samples were leftovers from health check-ups of elephants donated by veterinarians.

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Not applicable.

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Suwanchatree, N., Thanakiatkrai, P., Linacre, A. et al. Discrimination of highly degraded, aged Asian and African elephant ivory using denaturing gradient gel electrophoresis (DGGE). Int J Legal Med 135, 107–115 (2021). https://doi.org/10.1007/s00414-020-02414-w

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Keywords

  • DGGE
  • Ivory
  • Legal status identification