Scientists raise hopes of reviving extinct tiger
SCIENTISTS in Australia have mapped the genetic sequence of the extinct Tasmanian tiger, raising hopes of reviving the species, the last surviving example of which died in a zoo in the city of Hobart in 1936.
The landmark study of the Tasmanian tiger, or thylacine, was based on examination of DNA from a female cub that had been preserved in ethanol at a museum since 1909.
Andrew Pask, a researcher from the University of Melbourne, said that establishing a blueprint of the thylacine’s entire genetic code was the first step in trying to bring back the species. “As this genome is one of the most complete for an extinct species, it is technically the first step to ‘bringing the thylacine back’,” he said.
“We are still a long way off that possibility. We would need to develop a marsupial model to host the thylacine genome, like work conducted to include mammoth genes in the modern elephant.”
Tasmanian tigers became extinct on the Australian mainland about 3,000 years ago but survived on the island state of Tasmania.
The species was hunted by European settlers, who believed the animals threatened their sheep and who were encouraged by a government bounty of £1 per carcass. The last known tiger died in captivity in 1936, though the species was not officially declared extinct until 1982. But the genome study revealed that the sandy-coloured marsupial may have become extinct even if humans had not settled in Tasmania.
The sequencing found that the thylacine had little genetic diversity, making it harder for it to survive changes in environmental conditions.
“They were actually in pretty bad genetic shape and it wasn’t because of their isolation on Tasmania. It was a longer-term decline in their history,” Dr Pask said.
“We certainly made them go extinct there’s no question about that. But we now know even if [thylacines] were still around today they’d probably be in the same genetic dire circumstances as the Tasmanian devil [a local species that is under threat].” The Tasmanian tiger has a somewhat mythical status in Australia, and there is still frenzied speculation that it may have survived in the wild.
There have been regular reported sightings, though experts believe that the creatures spotted are probably feral dogs. Recent unconfirmed sightings in Queensland prompted a fresh search that has so far proven fruitless.
The study found that the genetic health of the thylacine became compromised about 70,000 to 120,000 years ago, an era that coincided with an ice age, and the species became isolated when the island was cut off due to rising seas about 14,000 years ago. On the mainland, the species became extinct because of extreme weather and drought, according to a study released this year.
Experts said it could take years – and billions of dollars – to revive the species. “We still have a way to go to get the technology and at a reasonable cost,” Christy Hipsley, from Museums Victoria, told Channel Seven.
However, Dr Pask said he believed humans had a moral obligation to try to revive the species. “I think we were responsible for hunting [the species] to extinction – in that case, we almost owe it to the species to bring it back,” he said.
The findings were published in the journal Nature Ecology and Evolution.