British researchers say they are developing a DNA test that could help nab those who illegally trade in tiger products. And three recent raids in India that confiscated huge caches of tiger bones and hides suggest that the need for such policing tools is greater than ever.
The number of wild tigers has plummeted from over 100,000 in the 19th century to perhaps 7000 now, according to United Nations (UN) officials. "Tigers are so highly endangered that they may soon be extinct in the wild," says Robert Hepworth of the United Kingdom's Department of the Environment. Last month, he led a three-member UN team that visited India and Japan to assess ways of stemming the illegal trade in tiger parts, which are highly valued by makers of traditional Asian medicines. The problem is that although officials can seize medicines that list tiger bone as an ingredient, they need proof of its presence to get criminal convictions. A tiger DNA test would be a "great boon" for law enforcement, says Hepworth.
Jon Wetton and his co-workers at the Forensic Science Service believe that amplifying fragments of the cytochrome b gene of the tiger's mitochondrial DNA may fill the bill. The test can detect "as few as 10 tiger cytochrome b gene fragments, considerably fewer than are present in a single cell," says Wetton. Tiger blood, hair, and bone samples have all generated positive results, he says. The researchers are currently spiking Chinese medicines with progressively smaller doses of tiger bone to determine the limits of the test's sensitivity. Once they succeed, the next test may come in a courtroom.