Scientists on Wednesday revealed they had unravelled much of the genetic code of a woolly mammoth, in what could be the first baby step in bringing the extinct creature, or at least characteristics of it, back to life.

Researchers from the U.S. and Russia, in a million-dollar project, said Wednesday they have sequenced more than three billion DNA bases of the mammoth nuclear genome, obtained from ancient hair shafts extracted from two specimens dating back roughly 20,000 years.

That represents roughly 80 per cent of the 4.17 billion DNA pairs they expect to find in the mammoth genome, assuming the mammoth genome is similar in size to that of modern African savanna elephants.

Stephan Schuster, a Penn State University biochemistry professor and co-author of the new research, said the early findings suggest it's only a matter of time before the complete sequence is obtained, raising the possibility that an extinct species could be brought back based on its genetic material.

"It could be done. The question is, just because we might be able to do it one day, should we do it?" said Schuster. "I would be surprised to see if it would take more than 10 or 20 years to do it."

The research, which also found that woolly mammoths split into two genetic groups about two million years ago, will be published in the Thursday edition of the journal Nature.

Hamilton, Ont.-based University of McMaster anthropology Prof. Hendrik Poinar wasn't part of the Nature study but has done pioneering work extracting nuclear DNA from bone in woolly mammoths. He said the research marks the beginning efforts in the quest to complete the mammoth genome, but cautions that it is only a beginning step.

"With sequencing of this sort, you want to get about eight to 12-fold coverage of the genome, so you can be reasonably sure of its accuracy," he told CBC News. "Here we are talking about a 10th of that coverage, so there's a large amount of room for error, but it's great as a proof of principle."

Fossil samples of bone and hair have already provided researchers with access to DNA from extinct animals. While bone and hair samples are more known as a resource for the more abundant mitochondrial DNA, the more revealing nuclear DNA can be found in the samples as well.

The issue with ancient samples is contamination: DNA from bacteria and other foreign life forms can mix with samples and degrade them. Schuster's group found a way around this by focusing on hair, which they found was easier to decontaminate.

The method used by the researchers isn't likely to be applicable to older creatures like dinosaurs, however, because whether the DNA can survive the rigours of thousands of years depends in large part on how undisturbed the specimen is by the ravages of its environment, Poinar said.

No Jurassic Park any time soon: Poinar

While the relatively unchanging permafrost of Siberia is capable of preserving specimens as old as 100,000 years, the time of dinosaurs was much warmer and the land mass they lived on was closer to the equator, unsuitable conditions for permafrost.

That means we won't be seeing Jurassic Park any time soon, said Poinar.

As for resurrecting a woolly mammoth, he said that while it's admittedly a fascinating idea, it's years away from reality because of all of the intermediary steps that would need to be taken.

"You would need to find a way to synthesize a full set of chromosomes from the genome data and right now we don't even know how many chromosomes it had," he said. "If you could do that, you could, in theory, take the chromosomes of an Indian elephant and alter them to those of a mammoth and then plant those chromosomes in an egg; you could then bring it to term," he said.

"But we need that chromosome information — right now we have no scaffold to build on," said Poinar.

It might be possible, however, to isolate ways in which the mammoth genome differs from modern-day elephants and possibly isolate a particular feature, according to an accompanying article in Nature. Svante Paabo, 53, of the Max Planke Institute for Evolutionary Anthropology in Leipzig, Germany, told the scientific journal such a creation represents the closest the public might come to seeing a mammoth in his lifetime.

With files from the Associated Press