Expediting the sampling, decalcification, and forensic DNA analysis of large elephant ivory seizures to aid investigations and prosecutions

Abstract

A B S T R A C TThe illegal ivory trade continues to drive elephant poaching. Large ivory seizures in Africa and Asia are still commonplace. Wildlife forensics is recognised as a key enforcement tool to combat this trade. However, the time and resources required to effectively test large ivory seizures is often prohibitive. This limits or delays testing, which may impede investigations and/or prosecutions. Typically, DNA analysis of an ivory seizure involves pairing and sorting the tusks, sampling the tusks, powdering the sample, decalcification, then DNA extraction. Here, we optimize the most time-consuming components of this process: sampling and decalcification. Firstly, using simulations, we demonstrate that tusks do not need to be paired to ensure an adequate number of unique elephants are sampled in a large seizure. Secondly, we determined that directly powdering the ivory using a Dremel drill with a high-speed cutter bit, instead of cutting the ivory with a circular saw and subsequently powdering the sample in liquid nitrogen with a freezer mill, produces comparable results. Finally, we optimized a rapid 2 -h decalcification protocol that produces comparable results to a standard 3-day protocol. We tested/ optimised the protocols on 33 raw and worked ivory samples, and demonstrated their utility on a case study, successfully identifying 94% of samples taken from 123 tusks. Using these new rapid protocols, the entire sampling and DNA extraction process takes less than one day and requires less-expensive equipment. We expect that the implementation of these rapid protocols will promote more consistent and timely testing of ivory seizures suitable for enforcement action.

Tracking the origin of worked elephant ivory of a medieval chess piece from Belgium through analysis of ancient DNA

“…A few communications by wildlife forensic investigators (e.g., the US Fish & Wildlife Service Forensics Laboratory) used DNA extracted from recent ivory carvings or idols to identify elephant species (Gupta et al, 2011). Recently, Ewart et al (2020) optimized DNA extraction protocols on both raw and worked elephant ivory and demonstrated that powdering the ivory directly with a drill, as well as short decalcification times (2 h), produces results comparable with sample powdering in liquid nitrogen and a longer decalcification time (3 days). In addition, sampling the cementum and using a total demineralisation DNA extraction method contribute to minimizing the amount of elephant ivory that is necessary in order to recover DNA (Winters et al, 2018).…”

A novel approach to combatting proboscidean ivory trafficking using a multiplex High-Resolution Melt (M-HRM) assay

“…The high success rate (97%) of this M-HRM assay can most likely be explained by (1) the use of a sanding technique for obtaining ivory powder, (2) small amplicon sizes, and (3) the use of an annealing temperature gradient. Sanding ivory into a fine powder, like cutting [14] or drilling ivory, then pulverizing the ivory in liquid nitrogen [6], increases the surface area available to react with EDTA during the overnight demineralization step [21]. EDTA decalcifies the ivory by chelating the metal ions, such as calcium (Ca 2+ ).…”

Three birds with one stone? Sex ratios of seized critically endangered helmeted hornbill casques reveal illegal hunting of males, females and juveniles

“…We collected genetic samples from 166 casques. We used a Dremel drill to collect 1.8–2.0 mg of powdered material per casque (Ewart et al ., 2020). Dried facial/gular skin was sampled where available using a sterile scalpel to cut approximately 1.5 × 1.5 × 3 mm (Mundy, Unitt, & Woodruff, 1997).…”