TORONTO - Scientists have sequenced much of the genome of the woolly mammoth, raising the tantalizing but remote possibility that one day the long-extinct mammal could be resurrected to again trudge through the Arctic snow.

The researchers at Penn State University extracted DNA from mammoth hair found frozen in the permafrost of Siberia, where the massive beasts once roamed up until about 10,000 years ago, before their species disappeared for good.

The ground-breaking work, published in Thursday's issue of the journal Nature, is the first time an extinct animal's genome has been decoded, and the first time DNA from an extinct animal was obtained solely from its hair.

And getting the bulk of that hair was a story in itself.

Co-author Stephan Schuster, a molecular biologist at Penn State, purchased two 10-gram balls of hair through eBay for US$130, after verifying the authenticity of the vendor and the artifact through a museum in Moscow.

The scientists have been able to sequence about 80 per cent of the behemoth's genome, comparing short snippets of DNA taken from the hair of 18 different animals entombed beneath the Siberian ice.

The research raises the notion that the ice age's woolly mammoth could be brought back to life, much as dinosaurs were resurrected in the film "Jurassic Park."

But Schuster and other experts call such a return from the dead a remote possibility -- and one fraught with lots of ethical considerations.

The easiest method would be cloning -- using similar technology to that which produced Dolly the sheep.

"There is absolutely no way that this will ever work, because there is no more intact chromosomes available from any tissue that you might want to look at, and people have looked very intensely," Schuster said Wednesday from State College, Pa.

"I'm saying direct cloning from a mammoth tissue cannot be done. This is an impossibility."

Theoretically, science could evolve to the point that researchers could one day put together genetic material that would approach the ancient creature's blueprint for life, using the yet-to-be sequenced genome of the modern elephant, the mammoth's closest biological relative.

"What I'm trying to say is there is a workable route to do that, but it is at this time technically and cost-wise and time-wise not feasible."

Hendrik Poinar, an evolutionary geneticist at McMaster University, called the work a great technological advance that has provided the most genetic data to date on an ancient organism.

Poinar, who was not involved in the research, said the findings will be a boon to scientists studying what evolutionary changes occurred that allowed mammoths to endure frigid temperatures. Mammoths and modern elephants once shared a common ancestor, but there was a split about six million years ago.

But as to bringing a woolly mammoth back to life?

"I think it would be silly to say that it's not possible to theoretically recreate a hybrid animal," he said from Hamilton. "You could take an Asian elephant's genes and modify them to reflect what the mammoth sequence was."

The altered chromosomes could be put into an female elephant's egg and gestated, said Poinar, who was a scientific consultant on "Jurassic Park."

"It's theoretically possible to do it, but it's a long, long long-shot. And probably the more pressing question is should it be done? Should we be talking about the resurrection of extinct animals and the ethics behind that? Why would we bring it back? What's the scientific question that we would try to address, apart from putting it in a park? There's really no good reason to do that."

Still, he mused that the movie's director may have been right when he defended its fictional premise of dinosaurs brought back from extinction.

"It was Steven Spielberg who said ... `this is the science of eventuality.' He probably was right in a sense."

Biologist Webb Miller, who led the $1-million DNA-mapping project with Schuster, said that while the mammoth research is "way cool," the team's real interest is finding ways to save endangered species. Their next project involves sequencing the genome of Australia's Tasmanian devil, whose survival is threatened by a type of cancer.

"If you want to study the genomics of extinction, the biological basis or the biological repercussions of extinction, then you want to be able to follow species ... that actually went extinct," Webb said.