Scientists: Mammoths could be brought to life with reconstructed DNA

Scientists are talking for the first time about the old idea of resurrecting extinct species as if this staple of science fiction is a realistic possibility, saying a living mammoth could perhaps be regenerated for $10 million.

The same technology could be applied to any other extinct species from which scientists can obtain hair, horn, hoofs, fur or feathers and which went extinct within the past 60,000 years, the effective age limit for DNA.

Though the stuffed animals in natural-history museums are not likely to burst into life again, these old collections are full of items that may contain ancient DNA that can be decoded by the new generation of DNA-sequencing machines.

If the genome of an extinct species can be reconstructed, biologists can work out the exact DNA differences with the genome of its nearest living relative. There are discussions of how to modify the DNA in an elephant's egg so that after each round of changes it would progressively resemble the DNA in a mammoth egg. The final-stage egg could be brought to term in an elephant mother, and mammoths might once again roam the Siberian steppes.

The same would be technically possible with Neanderthals, whose full genome is expected to be recovered shortly, but there would be several ethical issues in modifying modern human DNA to that of another human species.

A team headed by Stephan Schuster and Webb Miller at Pennsylvania State University report in today's issue of Nature that they have recovered a large fraction of the mammoth genome from clumps of mammoth hair.

Mammoths, ice-age relatives of the elephant, disappeared about 10,000 years ago when they were hunted to extinction by prehistoric humans.

Schuster and his colleagues read the sequence of genetic letters from fragments of DNA inside the shafts of the mammoth hair. The DNA was left from the cells that produce the hair protein, which stack up and die as the hair grows.

A chief advantage of using the hair-shaft DNA was that it was largely protected from contamination by microbes and other organisms whose DNA contaminates many ancient tissue samples.

Schuster and Miller calculated that the mammoth's genes differ at some 400,000 sites on its genome from that of the African elephant.

At present there is no way to synthesize a genome-size chunk of mammoth DNA, let alone to develop it into a whole animal. But Schuster said a shortcut would be to modify the genome of an elephant's cell at the 400,000 or more sites necessary to make it resemble a mammoth's genome.

The cell could be converted into an embryo and brought to term by an elephant, a project he estimated would cost $10 million.

"It could be done. The question is, just because we might be able to do it one day, should we do it?" asked Schuster, a biochemistry professor.

Not everyone is a believer. Rudolph Jaenisch, a biologist at the Whitehead Institute in Cambridge, said the proposal to resurrect a mammoth was "a wishful-thinking experiment with no realistic chance for success."

Information from The Associated Press and The Washington Post is included in this report.