Revive the extinct Tasmanian tiger through cloning?
| SYDNEY, AUSTRALIA
Ask any American who grew up on Sunday morning cartoons, and he or she will surely be able to recognize the infamous Tasmanian devil one of Bugs Bunny's ferocious yet lovable sidekicks from Down Under.
Ask the same people about the Tasmanian tiger, and they will most likely draw a blank. That's because the Tasmanian tiger became extinct long before it had a chance to audition for Warner Brothers.
All that may change, however, if a small group of Australian scientists have their way and do what some believe is the stuff of science fiction to clone an extinct animal from extracted DNA fragments.
Karen Firestone, a conservation geneticist with the Evolutionary Biology Unit of the Australian Museum in Sydney, together with Don Colgan, successfully extracted DNA from the remains of several museum specimens. This will serve as a DNA library for storing precious fragments for future reference, duplication, and genome reassembly.
In May, after two years of research, the scientists made a major breakthrough in the cloning project by successfully replicating the tiger genes using a process called PCR.
Dr. Colgan told the Australian press that the probability of success was slim, possibly between 4 and 10 percent. But despite that, the project is going ahead.
"It's a very brave and stupid person who says it's impossible," says John Shine, the executive director of Sydney's Garvan Institute of Medical Research. "Dolly the sheep was seen as impossible a decade ago," he adds.
The Thylacine (Thylacinus cynocephalus), as the Tasmanian tiger is more formally referred to, was once the largest known marsupial carnivore in Australia. With dark brown vertical stripes down its side and an enormous gape with canine-sized teeth, it's not surprising that it became known as the Tasmanian tiger or Tasmanian wolf. It has also been called a zebra wolf, wolf opossum, opossum hyena, and even a dog-faced Dasyurus.
Call it what you will, the Tasmanian tiger still has more in common with its Australian marsupial cousins, such as kangaroos, wallabies, and koalas, than with actual tigers, wolves, or hyenas. The real giveaway is the female's hidden pouch, albeit backward opening, for rearing its young.
Fossil records dating back some 4,000 years confirm that the Tasmanian tiger once roamed the entire Australian continent and as far away as New Guinea. Aboriginal rock paintings depicting the tiger have been found in Australia's Northern Territory.
For centuries, it thrived on the island of Tasmania until the arrival of the first European settlers in the early 1800s. They saw the tiger as a threat to their introduced flocks of sheep. Because of the occasional loss of livestock due to Thylacine predation, local Tasmanians waged an all-out war on the species, very much as ranchers in the American West have targeted the gray wolf.
The tiger's fate was sealed. In the 1840s with the establishment of government-sponsored extermination societies, which paid handsomely for trapping and hunting down the tiger. By 1900, some 2,000 bounties had been paid. The tigers' numbers were also dramatically reduced by an increasing loss of habitat, as settlers cleared land for agriculture and livestock.
Although the Tasmanian tiger was declared a fully protected species in the summer of 1936, it was too little, too late. The last known captive Thylacine, named Benjamin, died in the Hobart Zoo on Sept. 7, 1936.
Ever since Benjamin died, scientists, conservationists, and others have been trying to find evidence of the tiger's existence in the wild. Despite the numerous "sightings," there has been no real evidence to prove that the animal still exists. The only hard evidence that may ensure the future of this unique animal may just be in those bottled jars of ethanol sitting on a dusty museum shelf.
With the recent discovery last year of a well-preserved Tasmanian tiger pup in a jar of alcohol at the Australian Museum, scientists continue to believe there is a possibility of cloning the species back to life through DNA extraction. Michael Archer, director of the Australian Museum, says that "it may open the door for extinct animal populations to be reborn."
Others, however, are skeptical of such "Frankenstein science," and are concerned with the ethical questions of cloning and playing the "role of God." Many believe that the DNA is unlikely to be perfectly preserved and that no living creature is a close enough relative for a surrogate birth to be successful.
Mr. Archer responds to the criticism, saying that people "played God" when humans exterminated the animal in the first place. "To actually reverse extinction would be the biological equivalent of the first walk on the moon," he adds.
To carry out their Jurassic Park-style plan, scientists will face major financial hurdles. According to an Australian newspaper report, only $150,000 from government donations and private sources has been raised since 1999. It will take much more than that for such an ambitious project to get off the ground meaning that the search for the missing Tasmanian tiger continues.