21Mar2001 AUSTRALIA:
Chasing the tiger - CLASSMATE.
By SIMON BENSON.
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Some people know it as the Tasmanian Tiger, others call it the Tasmanian Wolf. Its real name, however, is the thylacine and it once roamed the Australian landscape as our own king of beasts - a top order carnivore akin to the tigers of Asia or the wolves of South America. It was at the top of the food chain, feeding on and striking fear into the hearts of kangaroos and other marsupials, as well as rodents and birds. Yet somehow this unique creature, that has captured the imagination of scientists and conservationists, was itself preyed upon - mainly by humans.
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In 1936, after 25 million years of evolution, the last known survivor died in Hobart Zoo. The species then became officially extinct. It is believed to be the only animal that has been completely killed off, primarily due to direct human interference. Scientists are now working to "right that wrong" by bringing the thylacine back to life.
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Borrowed from the fantasy of Jurassic Park, researchers at the evolutionary biology division of the Australian Museum, will extract DNA from a specimen preserved in alcohol and use it to reconstruct living clones. It is that specimen which is now the centrepiece of an entire exhibition at the museum, devoted to raising interest in the project. It is the first scientific project of its kind ever attempted and some people have criticised it for being "an expensive and self-indulgent exercise by scientists, trying to play God". If it succeeds it could create whole new science for biology conservation, ensuring that no more animal species on this planet are lost again. As well though, there was something drastically different about the thylacine, that set it apart from just about any other carnivore on earth. It had a head like a wolf and the body of a dog and massive jaws not seen in other animals.
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Unlike most carnivores on earth at the time, it was also a marsupial. Despite having enormous crushing teeth and powerful front limbs, it also carried the legacy of its marsupial heritage - it had pouches like kangaroos for carrying its undeveloped young. After millions of years of evolutionary change, only one member of this family remained - thylacinus cynocephalus, the Tasmanian Tiger. Yet, this animal, which adapted to the harsh Australian environment in a way very few large carnivores could, was completely wiped from the landscape in less than 4000 years.
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- First the introduction of dingos from Asia 4000 years ago, wiped them from the mainland. They were then confined to Tasmanina - hence their name - and when Europeans arrived they were hunted and shot through unfounded fears they were killing farmers' livestock. Leader of the cloning project, Don Colgan, is a geneticist with the Australian Museum. He says there is really a lot to be learned from the demise of the thylacine. "This animal was the sole relic of a family that dominated the Australian landscape for 25 million years," said Dr Colgan. "I think it is accepted that we feel a sense of guilt about what happened to this animal and are determined not to allow it to happen again.
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"The project itself centres on a specimen of a thylacine pup, preserved in alcohol for more than 100 years." Unlike other cloning projects involving living animals, trying to clone an extinct species ranges from being highly difficult to near impossible, because there are no living cells. This entire project could take as long as 20 years - because much of what they are attempting has not been tried before. And so what happens when it is brought back to life? The animal would have to be introduced to a habitat free of dingos, before being able to re-adapt to an environment that has changed since its extinction.
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Other DNA samples from specimens around the world would also have to be found to add to the genetic pool of the first thylacine population (to make sure the clones are not all too closely related). Professor Mike Archer, the director of the Australian Museum, says that one day the thylacine could also become a pet, just like the family dog. Back from the brink Other attempts to bring species back from the dead: * Last year scientists from Advanced Cell Technologies (ACT) in Massachusetts cloned a gaur, an endangered species of wild ox. This was the first case of a species being born by putting its DNA into the egg of another species. Noah the gaur was born by using the egg of a domestic cow, which shares characteristics with the gaur. Unfortunately, Noah died soon after birth but scientists say it was due to an infection not because it was a clone. ACT is planning to try this technique to create a bucardo, a species of Spanish mountain goat recently declared extinct. * The Norfolk Island morepork, a variety of boobook owl, was brought back from the brink by mating it with a similar species. In 1987 when the population dropped to one single female, two male New Zealand moreporks were introduced to mate with her. Although the two species are very closely related, the Norfolk Island morepork now only exists in hybrid form. Even if cloning had been available it is doubtful that with a population of one the species could return to sustainable levels.
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Cloning is only capable of producing copies carrying exactly the same genes, which means a lack of diversity. Currently technology is not up to introducing enough beneficial mutations to create diversity. Scientists cloning animals must find DNA specimens from several different gene pools. * Plans to revive animals such as dinosaurs and woolly mammoths based on the genetic fragments retrieved from dinosaur blood in fossilised mosquitoes or frozen mammoth carcasses are faced with this problem. There is probably not enough dinosaur DNA to create a real-life Jurassic Park. Bringing species back from extinction or even from endangered status is useless unless the conditions that endangered numbers in the first place are dealt with. With dinosaurs that might not be a problem since there is unlikely to be an asteroid to wipe them out again, but in the case of most vanished species, humans have destroyed their environment.
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Environment Australia says that cloning an extinct species that is no longer part of a functioning ecosystem is preservation not conservation. Cloning also does not form any part of its recovery plans for endangered species.
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- ON THE LOOKOUT BOOKS
*Tiger Tales By Col Bailey (Harper Collins 2001) $19.95
Tales from Col Bailey about the search for the Tassie tiger.
*Tasmanian Tiger By Marion Isham (Bandicoot Books) $9.95
Two children see a Tasmanian Tiger and follow a trail to find it.
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- PLACES
*The Australian Museum College St, Sydney.
This is where the debate over cloning the thylacine began and should be one of your first ports of call in Sydney when it comes to all things thylacine.
*Macleay Museum Gosper Lane, University of Sydney
Currently running two exhibitions about endangered and extinct species. Preservation deals with preserving specimens and Extinction deals with animals that have suffered at the hand of man.
*National Museum of Australia, Canberra
The newly-opened national museum has a display devoted to the thylacine and its path to extinction.
Source: DAILY TELEGRAPH (SYDNEY) 21/03/2001 P39