De-extinction: If we can save the white rhino, can we bring back the T-rex?

Wednesday, July 11, 2018

News that scientists have created hybrid white rhino embryos has given new hope to those who feared the northern white rhino was doomed to extinction.

But could scientists bring back other, longer-extinct species — and if so, should they?

The work to save the northern white rhino uses IVF technology, but that method is unlikely to work on an animal that has been extinct for thousands of years.

Swedish science journalist Torill Kornfeldt travelled the world researching "de-extinction" science for her book The Re-Origin Of Species.

She says Jurassic Park showed what the process is supposed to look like: scientists find an ancient mosquito trapped in amber, draw dinosaur blood from the perfectly preserved specimen, then use that DNA to clone the extinct reptile.

Except researchers have tried this and it doesn't work.

"They don't find any dinosaur DNA, they don't find any mosquito DNA either," says Kornfeldt, explaining that even well-preserved DNA degrades over time.

A mammoth task

So dinosaurs are probably out (as are Jurassic-era mosquitos) but what about something that died out a little more recently, like the woolly mammoth?

"The woolly mammoth is tricky," Kornfeldt says, predicting we could see a live mammoth in "either 15 years, or never".

"That research is still depending on a few scientific breakthroughs that haven't happened yet — but still might."

Even if those breakthroughs happen, the creature the scientists create won't be a cloned mammoth.

Cloning is only possible where there are tissue samples from a live animal, or "very recently dead" one.

Woolly mammoths have been extinct for thousands of years, so while there's still DNA in them, "it's really degraded".

Scientists can piece that DNA together in a computer by comparing it to a living relative, such as the Asian elephant.

"Kind of like looking at the lid when you do a jigsaw puzzle, you look at all the pieces and see where they're supposed to go," Kornfeldt says.

The next step is to identify the genetic differences between the elephant and the mammoth — genes that govern the animal's fur, for example — and then tweak the elephant's genes to make it more like a mammoth.
"You're basically mammothifying an elephant," Kornfeldt says.

Home sweet home

Once you have a herd of woolly mammoths, the next problem is where to put them.

Kornfeldt travelled to Siberia, where researchers are attempting to recreate a woolly-mammoth era habitat.

"This was a very rich ecosystem — in some ways it was comparable to the African savanna," she says.

"There were loads of animals on this grassland, and then when the Ice Age ended — and when humans came in — this ecosystem changed.

"A lot of animals, including the mammoth, disappeared ... and the grassland was replaced by forest," Kornfeldt says.

Without access to a live woolly mammoth, the researchers have wheeled in an unlikely substitute.
"They have this old, Soviet-era tank that they drive around and knock down trees with," Kornfeldt says.
"One of the functions of a mammoth, same as elephants, is to knock down trees so the grass has somewhere to go."

A genetic moonshot

Even if creating a woolly-mammoth-like creature were a possibility, why would we bother?

In selling the USA's original 1969 moonshot to the public, John F Kennedy famously talked up the benefits of taking on a massive challenge:
"We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organise and measure the best of our energies and skills."
Kornfeldt says cloning the woolly mammoth could have similar benefits to the Apollo program.
"We didn't go to the Moon to collect gold or something, we did it just to go through the process — and in the same way, going through the process of figuring something like this out has a great value in itself," she says.

"It makes the researchers a lot more aware of how different genes work and what their functions are, what kind of genes you can change and what genes you can't change, and how it all sort of fits together."



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