Will woolly mammoths live again?
By ANNE MCILROY
Tuesday, December 20, 2005 Page A1
SCIENCE REPORTER
Scientists have sequenced part of the genome of a woolly mammoth that died 28,000 years ago, a discovery that raises the possibility of bringing the extinct ice age mammals back from the dead.
Hendrik Poinar, a molecular evolutionary geneticist at McMaster University in Hamilton, says ancient DNA obtained from the jawbone of a long-dead Siberian woolly mammoth could be used create a modern version of the animal.
He and his U.S. colleagues won't be able to clone the female that was found frozen in the permafrost because the DNA they obtained was fractured into so many tiny fragments. But they could create a hybrid of the woolly mammoth and its closest living relative, the Indian elephant. Once researchers have made male and female hybrids, they could breed the animals to obtain as pure a woolly mammoth as possible.
"In theory, you could do it," Dr. Poinar says.
It could prove difficult in practice, however. Still, this is the most DNA from an ancient animal that has ever been found and sequenced, he says.
So far, he and his U.S. colleagues have mapped 1 per cent of the woolly mammoth genome, and they say they should be able to finish the rest in a year or two.
It will tell them the million or more differences between woolly mammoths and Indian elephants, and allow them to identify the genes that make a mammoth a mammoth, he says. The next step would be the most difficult -- changing the genetic material of the Indian elephant to make it resemble the hairier, humpier creatures that lived during the ice age.
Once those changes are made, an Indian elephant would also have to provide a donor egg, and act as a surrogate mother.
Ethical questions surround raising a species from the dead in this fashion, and McMaster is planning a conference to examine the issues. It could be cruel to bring an extinct animal back to life, even if researchers create a small population of woolly mammoths to keep each other company.
"Is it unfair to the animal?" Dr. Poinar asks.
There is also the Jurassic Park scenario, in which ancient animals brought back to life run amok.
Most woolly mammoths died out 10,000 years ago or more, although a small population lived on an island in Siberia as recently as 3,500 years ago.
"When the Romans were in Rome there were mammoths in Siberia," Dr. Poinar said.
The body of the animal that yielded so much DNA was exposed when a river bank in Siberia washed away. It was discovered by the Dolgans, the people who live in the area, who alerted Bernard Buigues, a scientist who runs an ice age museum in a Siberian ice cave.
The DNA was in such good shape because the animal never thawed, Dr. Poinar says. It wasn't fossilized, but mummified, a corpse preserved by the low temperatures. (People trapped by blizzards have survived by eating mammoth steaks, he says.)
There were 350 mammoths in the museum, and Dr. Poinar and his colleagues brought samples from them all back to Hamilton to examine each one for DNA.
They hit the motherlode with the jawbone of an animal that turned out to be a female. They were able to quickly sequence it using a relatively new technique.
"We were stunned," Dr. Poinar says. His team's findings will be published this week in the U.S. journal Science. He is now seeking funding to finish mapping the genetic code of the woolly mammoth genome, which will cost at least $5-million.
Mammoth research is a competitive business. Another researcher announced yesterday in the British journal Nature that he had sequenced DNA from the ice age creatures. But it was a much smaller amount, and from a part of the cell called the mitochondria that contains only sections of maternal DNA. Dr. Poinar and his colleagues mapped far more genetic material from the cell nucleus, with contributions from both parents.
Some researchers have long dreamed of bringing extinct animals back to life. But to successfully clone a long-dead animal they need a decent copy of the creature's DNA, and a compatible, living surrogate to provide an egg and a womb.
The longer a species has been gone, the harder it is. Fragments of DNA have been found on dinosaur bones, but it is hard to imagine a living creature that could serve as a surrogate mother.
Australian researchers are working on the Tasmanian tiger, a striped animal that ran like a wolf and carried her young in a pouch like a kangaroo. The tigers disappeared more than 60 years ago, and researchers are hoping they can clone one from the DNA of a fetus that was preserved in alcohol in 1866.
Researchers are also working on the burcado, a Spanish mountain goat. The last one died five years ago when she was hit by a falling tree. But researchers took a skin sample, and are hoping to clone her using a domestic goat to supply the egg and to act as a surrogate mother.
Both of these animals died out relatively recently. Dr. Poinar believes there is a better chance of bringing the woolly mammoth back to life than other ancient animals because the Indian elephant is such a close relative.
"It would be much harder with a sabre-tooth tiger."
