We Now Have a Full Genetic Map of the Extinct Tasmanian Tiger

Fagjun | Published 2017-12-13 22:56

Scientists have managed to sequence the entire genome of the Tasmanian tiger, revealing previously-unknown information on the species’s evolution and extinction.


Benjamin, the last known thylacine that died at Hobart Zoo in 1936

Benjamin, the last known thylacine that died at Hobart Zoo in 1936

 

 

Tasmanian tigers—also known as thylacines—were carnivorous marsupials that resembled striped dogs. They once thrived in Australia, but went extinct in the Australian mainland about 3,000 years ago. A small population managed to survive on the island of Tasmania, but the last known thylacine on the island died at Hobart Zoo in 1936. Wild thylacines may have survived a bit longer, perhaps into the 1940s, but this isn’t certain. In any case, the species was officially declared extinct in 1982.

 

Earlier this year, there were news of unconfirmed Tasmanian tiger sightings in Australia, though there have been several similarly unconfirmed reports of sightings of the same animal. Even so, researchers have also found that mathematically, it’s virtually impossible that Tasmanian tigers are still around. However, this may be the first time in years that there’s some good news about this long-gone animal, because its recently sequenced genome has turned out to be one of the most complete genetic maps of an extinct species.



Genetic Weakness


Tasmanian tigers had characteristics stripes on their backs. [Photo by the Tasmanian Archive and Heritage Office]

Tasmanian tigers had characteristics stripes on their backs. [Photo by the Tasmanian Archive and Heritage Office]

 

 

The 108-year-old remains of a female Tasmanian tiger pup has provided scientists with enough—and, more importantly, good quality—genetic material for genome sequencing. A new study on the thylacine genome has revealed quite a lot of important information on the species. For example, though the animal looks a lot like the Australian dingo, it’s actually more closely related to the kangaroo. However, Tasmanian tigers may look more like dingoes because both species have had to evolve and adapt in similar ecological niches.

 

The thylacine may look like a dingo, but it's actually more closely related to the kangaroo.

The thylacine may look like a dingo, but it's actually more closely related to the kangaroo.

 

 

Another compelling discovery is that Tasmanian tigers actually suffered from genetic weakness. Andrew Pask, one of the authors of the study, says that while overhunting was undoubtedly to blame for the thylacine’s extinction, the species was actually already in trouble way before it came into contact with humans. If Tasmanian tigers were still around today, they would be more prone to contracting diseases due to their genetic weakness.

 

Researchers thought that the genetic weakness in thylacines was caused by low genetic diversity due to isolation on Tasmania, but they found that the weakness appeared long before that. “[W]hat we found is that the population declined about 70,000 years ago, long before it was isolated meaning it probably had more to do with changes in the climate back then,” says Pask.



Resurrection


A hunter carries a freshly killed thylacine. [Photo by Universal History Archive/UIG via Getty Images]

A hunter carries a freshly killed thylacine. [Photo by Universal History Archive/UIG via Getty Images]

 

 

What’s exciting about the fact that the Tasmanian tiger genome has been sequenced is that there’s a chance that the species may be brought back to life. Pask believes that humans have a sort of moral obligation to bring Tasmanian tigers back, since we were responsible for their demise.

 

Of course, resurrecting an extinct species is not nearly as simple as it sounds. Still, the prospect sounds a lot more possible now than it did a couple of decades ago. However, Pask warns that sequencing the thylacine genome is only a step forward. Building a functional genome is also necessary, but that’s a whole other task that has yet to be done.

 

While the de-extinction of Tasmanian tigers isn’t impossible, it may not actually be doable in at least a decade. Then again, who knows? It’s possible that the necessary technology may be developed sooner than expected.

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