Frogs that are part alpaca and other genetically engineered wildlife could soon be running and hopping around Australia.
Artificial adaptations to disease, feral pests and climate change are all possible because of advances in tools that allow scientists to “edit” DNA — the genetic instructions of living organisms.
And genetically altered mosquitoes, quolls, and cane toads may soon be released into the Australian wild.
In the case of Australia’s 200-plus frog species, the technology could help make the amphibians resistant to a deadly disease introduced to the country in the 1970s.
Six (or possibly seven) species of Australian frogs are believe to have gone extinct at least partly due to the chytrid fungus.
Loading…
The highly virulent fungus causes the deadly disease chytridiomycosis which damages a frog’s skin, changing how it breathes and absorbs water.
“There’s just no way of really protecting frogs around the world against this disease,” University of Melbourne zoologist Stephen Frankenberg said.
“Although you can treat the individual frogs … you can never get rid of the fungus from the environment.”
So Dr Frankenberg is instead looking to use genetic engineering to stop frogs getting infected in the first place.
And it involves alpacas.
Woolly solution to a hairy problem
Alpacas (Lama pacos), a woolly herd animal from the Peruvian mountains, have become an unassuming star of medical research in the creation of new vaccines and treatments.
This is because they — and other members of the camelid family, such as camels and llamas — have a rare and useful ability.
Alpacas have a unique immune system that creates “nanobodies” which can be used in vaccine development. (iNaturalist: Scott Ramos, Alpaca, CC BY-NC 4.0)
Tiny immune particles derived from an alpaca’s blood can provide protection against diseases in other species.
When an alpaca is infected with a pathogen, its body creates a specialised type of very small antibody, called a “nanobody”, that lends itself to being produced by something called a “transgene”.
Transgenes are genes that are taken from one organism — like a plant, bacterium or animal — and then introduced into the DNA of a different one.
So a transgene taken from an alpaca and introduced into another species will create nanobodies in that other species.
This work of snipping genes is possible with genetic tools like CRISPR-Cas9, which is basically a pair of molecular scissors allowing precise cuts in DNA.
University of Melbourne zoologist Stephen Frankenberg. (ABC Science: Peter de Kruijff)
Dr Frankenberg’s plan is to infect alpacas with chytridiomycosis to see what antibodies the alpaca makes in response.
“That can then be used in a genetic engineering solution to chytrid infection,” he said.
“Then for each frog species, you could simply inject that [engineered] fragment into the eggs of that frog species … and then breed them up in captivity.”
This would give the frogs an inheritable gene that could spread via interbreeding once they’re released into the wild.
“It would be like a cookie-cutter kind of a solution that could be dropped into the genome of any frog species, potentially, because there are so many species that are impacted by chytrid disease,” Dr Frankenberg said.
At this stage, Dr Frankenberg is trying to find the right transgene, and then the first lab tests will be done with invasive cane toads (which are vulnerable to chytrid fungus).
US gene technology company Colossal is bankrolling the project with $3 million over three years.
The ambitious attempt to de-extinct a frog
Colossal funds other genetic projects for living species, but also aims to use genetic engineering to create proxies of extinct animals such as mammoths and dodos.
Earlier this year the company claimed it had brought back a long-extinct species of large American wolf, the dire wolf (Aenocyon dirus).
Specifically, it had made 20 changes to 15 genes of grey wolves (Canis lupus) to make them resemble the dire wolf.
Now, the US company has set its sights on the extinct “Tasmanian tiger” or thylacine.
De-extinction tech for conservation?
The last known thylacine (Thylacinus cynocephalus) died in captivity in 1936.
Andrew Pask with a skull of a thylacine that was killed during Tasmania’s bounty program. (ABC Science: Peter de Kruijff)
The University of Melbourne’s Andrew Pask, which is also Colossal’s chief biology officer, wants to see thylacines “roaming wild across all of Tasmania” again.
“We know that if there’s a big apex predator around, it excludes things like cats from regions,” he said.
“And then, ultimately, I might be alone on this, but I would love to see [thylacines] across all of mainland Australia.”
Professor Pask has been using historical samples from bones and preserved specimens to work out the complete set of DNA or genome of the extinct species.
A study on the genome is expected to be published later this year.
With genome in hand, Professor Pask’s lab will attempt to make millions of genetic edits to a living thylacine relative, such as the fat-tailed dunnart (Sminthopsis crassicaudata), to recreate a thylacine.
Fat-tailed dunnarts are like a “lab rat” for carnivorous marsupial research. (ABC Science: Peter de Kruijff)
The thylacine de-extinction project could also help conserve other native animals.
Toad-munching quolls
Professor Pask said thylacine funding had helped him achieve more for marsupial conversation in the past four years than he had in the previous 20.
“Where [gene editing] will really have an impact for our world is … conservation,” he said.
Dr Frankenberg recently edited dunnart cells (which he studied for the thylacine project) to make them resistant to the toxin of the invasive cane toad.
The northern quoll has seen declines across its range in WA, NT and Queensland. (iNaturalist: duke_n, northern quoll, CC BY-NC 4.0)
He says this technique could be used for a species like the northern quoll (Dasyurus hallucatus), which has been dying out after the arrival of the cane toad.
“It could be a couple of years really to get to the point of being able to produce quolls that are resistant to cane toads,” Dr Frankenberg said.
“It’s such a tiny edit and something that could arise naturally in the wild.”
Zoologist Stephen Frankenberg with a fat-tailed dunnart at the University of Melbourne. (ABC Science: Peter de Kruijff)
Colossal also claims to have developed an artificial womb prototype which could help it breed engineered thylacines without the need of a surrogate mother.
And there could be benefits for other marsupials.
“If we can do that, then all of a sudden we have an ability to produce en masse marsupials using this [artificial womb],” Professor Pask said.
“That could be a game-changer for us in Australia because we know we are really impacted by adverse weather events, particularly bush fires … where you can lose hundreds of marsupials from a particular landscape.
“We would like to have the ability to be able to create 100 koalas or 100 brushtail possums or whatever it might be to rewild back into that landscape.”
This could theoretically be done with biological material from a storage facility called a biobank.
Museums Victoria conservation geneticist Joanna Sumner. (Museums Victoria: Eugene Hyland)
Museums Victoria has teamed up with the University of Melbourne to build a biobank that freezes cell samples from Australia’s unique species to safeguard against extinction.
Biobank founder Joanna Sumner, a conservation geneticist for the museum, said the project had thousands of samples from 77 different species after four years of operation.
“We are using a lot of techniques that have been used in human biology for years,” Dr Sumner said.
“But now the technology is better, it’s cheaper, and we’re able to apply these techniques to wildlife.”
What could go wrong?
Deakin University ecologist Euan Ritchie said new conservation tools such as genetic editing were exciting, but they come with the risk of unintended consequences.
Tinkering with northern quolls could have a ripple effect on the broader ecosystem, he said.
“What if all of a sudden because cane toads are edible to all these northern quolls, you end up with huge numbers of northern quolls?
“And how might they affect other species that also share that environment?”
Fixing one problem, Professor Ritchie said, could end up creating another.
Introducing biological controls in Australia has had its share of successes (rabbit viruses) and catastrophic failures (cane toads).
But Dr Frankenberg said these risks could be mitigated by introducing gene-edited northern quolls on islands first, to study their effect on the ecosystem there.
“And then that might progress to releases on the mainland,” he said.
Listen to the full episode of Artificial Evolution about gene editing wild animals for conservation, and follow the podcast for more.