Researchers have devised a genetic map of Africa's elephants enabling investigators to pinpoint the exact region where an illegal shipment of ivory originated.

Turning a small chunk of ivory into a fine powder, scientists were able to extract the ivory's DNA. This was then compared to a genetic map of Africa's elephants, revealing which country produced the ivory.

The advance could not have come at a better time.

Nearly two decades after the Convention on International Trade in Endangered Species (Cites) introduced a global blanket-ban on the sale of ivory, the illegal trade has now reached the highest levels ever reported.

Organised crime syndicates have been blamed for the record levels of ivory being shipped across the world. For some gangs, ivory has become more lucrative - and easier to move - than illegal drugs. At least 23,000 elephants were killed for their tusks last year.

The greatest difficulty scientists had to overcome was working out how to extract the DNA. The ivory has to be reduced to dust but previous attempts to powder it through heat had destroyed the DNA. Borrowing a method used by dentists, researchers at the University of Washington used a machine that freezes the ivory at minus 240�C, making the ivory brittle enough to be turned into powder while still preserving the DNA.

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

By studying seized shipments, researchers will be able to identify poaching "hot spots", allowing governments to invest resources in the right places.

It is not only elephants that may benefit from the scientific breakthroughs. Similarly pioneering DNA methods have been used to prove the true identity of seal penises, thought by some to be a powerful aphrodisiac. But geneticists who travelled the world buying seal penises discovered that one-in-three had actually come from a different animal.