DNA tracking to fight ivory trade

A scientific breakthrough has been heralded as a potential saviour for tens of thousands of elephants hunted for their ivory. Researchers have devised a genetic map of Africa's elephants which - for the first time -has enabled investigators to pinpoint the exact region where a shipment of ivory originated.

The advance could not be more timely. Eighteen years after the Convention on International Trade in Endangered Species (Cites) brought in a global ban on the sale of ivory, the illegal trade has reached the highest levels ever reported.

The price of a kilogram of ivory was $100 in 1989, when the ban was introduced. In the following few years it fell to as low as $10. But by this year the price rocketed to $850 (£440) making the largest tusks worth thousands of dollars. For some crime syndicates, ivory has become more lucrative - and easier to move - than illegal drugs. At least 23,000 elephants were killed for their tusks last year.

"These are urgent problems," said Dr Samuel Wasser, the director of the University of Washington's Centre for Conservation Biology, where the DNA methods have been pioneered. "Poaching is the worst it has been in history. There is an enormous market for ivory in the Far East. There is an insatiable demand."

The greatest difficulty for the scientists was working out how to extract the DNA. The ivory has to be reduced to dust, but previous attempts by other scientists to powder it through heat had destroyed the DNA. The researchers at the University of Washington borrowed a method used by dentists to grind teeth to dust. Using a machine that freezes the ivory at -240C, they were able to make it brittle enough to be turned into powder, and the DNA was preserved.

By collecting elephant dung from across Africa and extracting the DNA, the researchers produced a map detailing the genetic make-up of the continent's elephants. Once the DNA of the ivory was known, Dr Wasser simply compared it to the map.

The theory was put to the test when his team studied the largest-ever haul of illegal ivory. More than 500 tusks had been seized in Singapore in 2002. Some 37 were tested, and all matched the genetics of elephants from Zambia and its surrounding savannah. Zambia's director of wildlife has since been replaced, and laws on ivory smuggling have been tightened.

Similar pioneering DNA methods have been used to prove the true provenance of seal penises, thought by some to be a powerful aphrodisiac. Geneticists who travelled the world buying seal penises found that one in three had come from a different animal.

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