Wednesday, May 21, 2008

Extinct Tasmanian tiger gene 'resurrected'



A two-week old mouse fetus, with blue showing thylacine DNA.


Scientists have brought back to life a gene from the extinct Tasmanian tiger, seen here,
after implanting it in a mouse.


Scientists said yesterday they had "resurrected" a gene from the extinct Tasmanian tiger by implanting it in a mouse, raising the future possibility of bringing animals such as dinosaurs back to life.

In what they describe as a world first, researchers from Australian and US universities extracted a gene from a preserved specimen of the doglike marsupial - formally known as a thylacine - and revived it in a mouse embryo.

"This is the first time that DNA from an extinct species has been used to induce a functional response in another living organism," research leader Andrew Pask, of the University of Melbourne, said.

The announcement was hailed as raising the possibility of recreating extinct animals.

Mike Archer, dean of science at the University of New South Wales, who led an attempt to clone the thylacine when he was director of the Australian Museum, called it "one very significant step in that direction".

"I'm personally convinced this is going to happen," he said. "I've got another group working on another extinct Australian animal and we think this is highly probable."

Dr Pask said that while recreating extinct animals might be possible one day, it could not be done with the technique his team used on the Tasmanian tiger.

"We can look at the function of one gene within that animal. Most animals have about 30,000 genes," he said.

"We hope that with advances in techniques, maybe one day that might be possible, but certainly as science stands at the moment, we are not able to do that, unfortunately.

"We've now created a technique people can use to look at the function of DNA from any extinct species, so you could use it from mammoth or Neanderthal man or even dinosaurs if there's some intact DNA there."

The last known Tasmanian tiger, which took its name from the Australian island and the stripes on its back, died in captivity in the Hobart Zoo in 1936, having been hunted to extinction in the wild in the early 1900s.

Some thylacine pups and adult tissues were preserved in alcohol, however, and the research team used specimens from Museum Victoria in Melbourne.

"The research team isolated DNA from 100-year-old ethanol-fixed specimens," the scientists said.

"After authenticating this DNA as truly thylacine, it was inserted into mouse embryos and its function examined. The thylacine DNA was resurrected, showing a function in the developing mouse cartilage, which will later form the bone."

Marilyn Renfree, of the University of Melbourne, cautioned that the recreation of extinct animals was not the aim of the research.

"Maybe one day this might be possible but it won't happen in my lifetime. It might happen in my children's lifetime, but there's so many steps we need to achieve before you could actually make this work."

The prospect of bringing extinct animals back to life caught the public imagination after Steven Spielberg's 1993 film Jurassic Park, based on the novel of the same name by Michael Crichton. In that story, dinosaurs are cloned from genetic material found in mosquitoes that had sucked their blood before becoming preserved in amber.

SCMP. May 21, 2008.

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