Mitochondrial DNA Profiling to Combat the Illegal Trade in Tortoiseshell Products

Erin L Lacasella,Amy Frey,Michael P Jensen,Christine A Madden Hof,Peter H Dutton,Ian P Bell

doi:10.3389/fmars.2020.595853

Abstract

Hawksbill turtles (Eretmochelys imbricata) are exploited for their beautiful shell known as tortoiseshell or bekko, making them extremely vulnerable in the illegal global trade of tortoiseshell products. In this study, we developed an effective, standardized method using a commercially available kit to extract DNA and obtain informative mitochondrial DNA (mtDNA) control region sequences (~800 bp) from hawksbill turtle products in order to trace the sample back to a likely stock origin. We also sequenced additional skin samples from nesting beaches of Milman Island, Australia and Arnavon Island, Solomon Islands to add to the baseline data for hawksbill turtles in the Indo-Pacific. Our results indicate that nine of the 13 tortoiseshell products obtained from Papua New Guinea and Solomon Islands were from turtles with haplotypes found primarily at the Solomon Islands rookery and did not match those from nesting populations in Australia or SE Asia, with the exception of one haplotype also found in 3% of turtles at Milman Island. We also found that 23% of the market samples have haplotypes only documented in foraging populations, which illustrates the urgent need for more extensive sampling of rookeries to fill gaps in the reference baseline database. Nevertheless, our study results demonstrate an effective methodology for obtaining DNA of sufficient quantity and quality from hawksbill turtle products.

Highlights

The illegal trade in endangered wildlife is having devastating impacts on many of the world’s species and is broadly considered a global threat to biodiversity (Veríssimo and Wan, 2019)
We aim to (1) Extract genomic DNA and sequence the mitochondrial DNA (mtDNA) control region from both skin and carapace samples from the same individual to serve as a positive control for accurately assigning mtDNA haplotypes from shell samples, (2) Use tortoiseshell product to refine the DNA extraction and sequencing method from processed shell products and (3) Sequence additional skin samples from nesting beaches of Milman Island, Australia and Arnavon Islands, Solomon Islands to add to the baseline data for hawksbill turtles in the Indo-Pacific
The results of our study demonstrate an effective methodology for obtaining informative mtDNA control region sequences (∼800 base pairs) from hawksbill turtle products

Summary

Introduction

The illegal trade in endangered wildlife is having devastating impacts on many of the world’s species and is broadly considered a global threat to biodiversity (Veríssimo and Wan, 2019). Rapid globalization, increased connectivity, complex trade networks, and a continued cultural and social demand for wildlife products will continue to drive populations toward extinction (Miller et al, 2019; Hitchens and Blakeslee, 2020). The illegal wildlife trade is highly profitable and estimated to have an annual value of 20 billion US dollars (Nahill et al, 2020). Genetic approaches have provided a useful tool in wildlife forensic investigations. The use of DNA sampling provides a time-efficient and cost-effective way to determine the species and in some cases geographical origin of wildlife products.

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Conclusion