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Captured with forensics

samedi 21 novembre 2009

DNA results from Ashland lab lead to arrests of ivory smugglers in Thailand Evidence in an international ivory smuggling case wound its way through the labyrinthine halls of a federal wildlife forensics lab in Ashland over the past year and led authorities to two men in Thailand this week.

Police in Bangkok arrested two Thai men and charged them with smuggling African ivory into Thailand to supply shops that sell jewelry and trinkets, including to customers in the United States, The Associated Press reported.

The United Nations Convention on International Trade in Endangered Species banned all international ivory trade in 1989. However, the ban didn’t address domestic trade.

Groups that work to stop illegal wildlife trade say smugglers increasingly have turned up in Thailand, where they sidestep the ban by mixing African ivory with tusks from domestic sources and then claim it all comes from Thai elephants. The tactic is effective because without DNA testing, it’s difficult to tell the difference between African and Asian ivory, the AP reported.

That’s where the U.S. Fish and Wildlife Service Forensics Lab in Ashland comes in.

Wildlife forensic scientist Bob Hoesch has researched techniques to recover DNA from ivory, then pinpoint the species it came from.

He developed his method about five years ago. Since then, the Ashland lab has processed a growing amount of ivory.

"We get a lot of ivory," Hoesch said.

When whole tusks come in, morphologists — biologists who specialize in the forms and structures of animals — examine them to determine whether they came from an existing species or an extinct one, he explained.

The ivory that undercover officers bought in the Thai case included both large pieces of tusk and carved figures and trinkets, Hoesch said.

The morphologist’s report indicated it was from an elephant, but it was up to Hoesch to figure out the details.

Ivory, the hardest substance in the body, is a tooth.

"The tooth is made of cells that produce enamel," Hoesch said. "Then those cells die and remain scattered inside — like raisins in a muffin."

The scattered, long-dead cells contain the DNA that Hoesch is looking for, but "the amount and quality of DNA is low," he said.

He carves off a small piece — about two grams — of ivory and pulverizes it to a powder. In a lab dedicated to finding and isolating trace evidence, such as a single drop of blood on an article of clothing or a few scattered cells locked in ivory, Hoesch extracts the DNA from the cells.

He then examines the strands of genetic material to find the key portions that, essentially, make an elephant an elephant.

Of the millions of tiny building blocks that make up a strand of DNA, "much is the same in every living thing," Hoesch explained. "Other parts are different in every individual."

What he’s looking for is the stretch that remains constant across every member of a species, but is unique to just that species.

When he finds that segment, he can quickly make billions of copies of it in the lab. With plenty of this key bit of DNA to examine, Hoesch then compares it to a vast library of known genetic material to determine what species the original tusk came from.

His work showed that the samples undercover officers bought in Thailand came from an African elephant, not a native animal whose ivory could be legally traded within its home country.

In the wake of the arrests in Bangkok, the U.S. Fish and Wildlife Service touted the cooperative effort.

"Monday’s arrests are significant in that they remove two more players from a global black market that threatens the survival of Africa’s elephants," agency spokeswoman Tamara N. Ward said in a statement reported by the AP. "This case also spotlights the importance of international cooperation in efforts to shut down illegal wildlife trafficking."

By Anita Burke, Mail Tribune November 21, 2009

Voir en ligne : http://www.mailtribune.com/apps/pbc...


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