DNA sleuths target ivory poachers

Ivory, which is essentially a form of tooth structure, has only tiny amounts of DNA contained within it, yet Professor Linacre says the new test procedure can work with only a tiny amount of connected DNA to return results of perfect accuracy.

Elephant populations have been greatly reduced, mainly due to illegal poaching for their ivory. While the trade in elephant products is protected by national laws and CITES agreements to prevent further population declines, ivory poaching and illegal trade in ivory persists. 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. It has been difficult to determine the necessary differences by tests alone.

"This means the enforcement of legislation needs to classify the legal status of seized ivory products," explains Professor Linacre. "Many DNA-based techniques have been previously reported for this purpose, although these have a limit of detection not suitable for extremely degraded samples. Now, this new technique has made a great leap forward."

Historically, the tiny amounts of DNA contained in tusks has made tracking the origins of ivory goods very difficult -- and why much of the poached ivory is shipped to Asia and swiftly broken down into tiny pieces, primarily for jewellery and trinkets that can be easily resold and does not allow easy or accurate DNA tracing.

However, the new process can confirm the legal or illegal status of seized ivory samples, even where it is assumed that the DNA will be highly degraded.

The results of the testing -- "Discrimination of highly degraded, aged Asian and African elephant ivory using denaturing gradient gel electrophoresis (DGGE)," by Nitchakamon Suwanchatree, Phuvadol Thanakiatkrai, Adrian Linacre and Thitika Kitpipit -- have been published in the International Journal of Legal Medicine.

In these tests, DNA from aged ivory was tested for reproducibility, specificity, and, importantly, sensitivity. Blind testing of 304 samples resulted in 100% identification accuracy. It also resulted in correct assignment in the legal status of 227 highly degraded, aged ivories within the test cohort, thus underlining the high sensitivity of the process.

The result of these successful tests will have international implications for the illegal trafficking and poaching of ivory, says Professor Linacre.

"This research output -- which is part of our continuing analysis of forensic DNA technology to accurately analyse smaller amount of DNA -- will be beneficial to help analyse ivory casework samples in wildlife forensic laboratories, and ultimately help to identify ivory poaching hotspots."