Scientists extract DNA from hawksbill turtle products to help save species
Posted on 17 August 2019
A novel method that in the future could be a major weapon against small and large-scale operations still targeting hawksbills for the illegal trade.
Scientists have developed a test to extract DNA from hawksbill turtle products including tortoiseshell jewellery. It’s a breakthrough that could help save the species, hunted for their beautiful shells, and now listed as critically endangered on the International Union for the Conservation of Nature (IUCN) Red List.
A study this year found humans harvested 9 million hawksbill turtles over the past 150 years, more than six times previous estimates. A 2008 IUCN assessment estimated there may be only 6,760 breeding females left in the Indian and Pacific Oceans. This number is likely to now be significantly lower.
The DNA extraction project involved the World Wide Fund for Nature-Australia in a collaboration with scientists at the NOAA Fisheries’ Southwest Fisheries Science Center (SWFSC) in California, USA.
Hawksbill turtles from different regions are genetically distinct. If authorities can test seizures of illegal tortoiseshell products, they can pinpoint which populations are being targeted by poachers and direct policing efforts to those areas. A novel method that in the future could be a major weapon against small and large-scale operations still targeting hawksbills for the illegal trade.
In developing the test, WWF research consultant Dr Michael Jensen, working with NOAA scientists, faced obstacles.
Shell often contains degraded DNA compared to fresh tissue. The heat and chemical treatments used to create tortoiseshell products could further damage DNA. But the team was able to modify a commercially available DNA extraction kit to effectively work on hawksbill shell products.
“It was a relief to confirm that we could get high-quality sequences from the shell products. By adapting an available kit that uses standard lab equipment, we’ve created a practical solution. Soon others will be able to easily repeat our proven method and extract DNA from tortoiseshell jewellery, whole shell or pieces of shell,” Dr Jensen said.
Thirteen tortoiseshell jewellery items, sourced from local markets in Papua New Guinea and the Solomon Islands were tested in NOAA’s genetic lab in La Jolla, California, USA.
“We extracted and sequenced mitochondrial (mt)DNA, inherited from mothers. When females lay eggs they always return to the beach where they hatched, so their DNA tells us their nesting origin,” Dr Jensen said.
DNA was successfully extracted from 12 of the 13 items. Of those 12, eight were associated with either PNG or the Solomons. The other four had no known nesting origin. This is because most hawksbill populations in the Asia Pacific region have not yet had their DNA signatures characterised.
The next step in the project is to build a more comprehensive genetic database of all hawksbill rookeries. Some genetic information has been published by scientists and other organisations over the years but there are many gaps to fill.
The DNA test and subsequent database will not only fight the illegal trade. Combined with tagging and satellite tracking, DNA will help identify all hawksbill populations, how they are connected, where they go, and which rookeries are most at risk from poaching.
WWF-Australia is working with local scientists and communities to develop ShellBank - a baseline dataset being established across Asia-Pacific for hawksbill rookeries.
Building a comprehensive genetic database has been a long-standing goal for NOAA scientists in order to accurately carry out population assessments and evaluate threats for these migratory species.
“This work is only possible through extensive partnerships with scientists, government, non-profit organizations and village communities living at the remote nesting sites around the Pacific,” said Dr Peter Dutton who has led NOAA’s Marine Turtle Genetics Program for over two decades.
“Having a reference collection of DNA and standardized analytical tools will allow us to build databases that serve as baselines to assess the impacts of additional threats, such as fisheries by catch,” said Dr Dutton.
This kind of information is currently unavailable and will provide vital information for wildlife managers and law enforcement to act on.
WWF announced the DNA breakthrough at the 18 th meeting of the Conference of the Parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES CoP18) in Geneva, Switzerland. Christine Madden Hof, Marine Species Project Manager WWF-Australia, raised concerns the CITES meeting will delay urgently needed action to protect hawksbills.
“It appears recommendations to crack down on the illegal marine turtle trade will be delayed until CoP19 which is not until 2022,” Ms Madden Hof said. “Hawksbills are disappearing. I urge CITES countries to act, right here and right now, before it’s too late. WWF is also calling on nations to help build the genetic database and to use it to fight the illegal hawksbill trade,” she said.
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