BSometimes revisions occur in unexpected places. Researchers working on an international push to bring back the thylacine say they found theirs in a long-neglected bucket at the back of a shelf at a Melbourne museum.
It contained a surprisingly well-preserved head of an extinct marsupial also known as the Tasmanian tiger.
“It actually had the head in a bucket of ethanol in the back of a cupboard, it had the skin removed and it sat there for about 110 years,” said Professor Andrew Bask, head of the integrated genome of the thylacine. Regenerative Research (abbreviated as Tigrr) says the lab at the University of Melbourne.
“It was very rotten, an absolutely horrible sight. People cut it into big pieces.”
Aesthetics aside, the model had a lot going for it. It contained material that scientists had thought impossible to find, including long RNA molecules crucial to reconstructing the genome of an extinct animal. “That’s the miracle that happened with this model,” Bask says. “It blew my mind.”
A year later, he says it has advanced the work of a team of Australian and American scientists trying to resurrect the species beyond what was expected at this point. “We’ve gone further than I thought, and we’ve accomplished a lot of things that were very challenging and that others said were impossible,” he says.
A plan to ‘extinct’ the thylacine
The thylacine reintroduction project is being driven by Colossal, a Texas-based biotech “de-extinction and species conservation” company that aims to recreate the woolly mammoth and todo using genetic engineering techniques.
Led by technology and software entrepreneur Ben Lamm, Colossal has raised US$235 million, employs 155 people directly and funds research in 13 laboratories around the world. Among them is the Tiger Lab, which operates at the University of Melbourne Biological Sciences.
The thylacine is Australia’s only marsupial apex predator. It once lived across the continent, but was restricted to Tasmania around 3,000 years ago. With its dog-like appearance and stripes on its back, it was widely hunted after European colonization. The last known survivor died in captivity in 1936, and it was officially declared extinct in the 1980s.
Colossal says researchers have made several advances in its work on the species, putting the company closer to its goal of returning to the wild. It includes what they say is the highest-quality ancient genome ever produced, with just 45 gaps in a genetic map containing 3 billion pieces of information.
Lam says it’s an “incredible scientific leap” that puts the project “on the path to wiping out the thylacine,” while other recent advances could prove useful in protecting the endangered species. “We are trying as fast as possible to develop the science necessary to make extinction a thing of the past,” he says.
The soft tissue of the Museums Victoria specimen, which the researchers called a “head in a bucket”, contained long preserved sequences of DNA – the same genetic material found in every cell nucleus in a body – but also long RNA molecules. Bask says the latter is important and unexpected.
RNA is much less stable than DNA. It differs in different types of tissues and consists of efficient reading of active genes required for a particular tissue to function. This means the researchers were able to obtain information about the animal’s nose, eyes, tongue and other facial features, giving a picture of what the thylacine tastes and smells like, what kind of vision it has and how its brain works.
The resulting first annotation is an extinct animal gene, Basque says. “It helps prove that what we’re bringing back is actually a thylacine and not some hybrid animal,” he says.
Thylacine researchers aim to take stem cells from living organisms that contain DNA identical to thylacine. Fat-tailed Dunnardand transform them into the closest approximation of thylacine cells using gene-editing expertise developed by George Church, a professor of genetics at Harvard Medical School and co-founder of Colossal.
The thylacine looks like a thing – but what comes next?
The announcement of genetic breakthroughs came ahead of an event at the SXSW festival in Sydney on Friday where Lamm and Bask will talk about their work with actor Luke Hemsworth. The Hemsworths are vocal and financial supporters of the project.
Colossal says it has also developed the first artificial reproductive technology to induce ovulation in marsupials, leading to captive breeding programs for threatened species, and to fertilize single-cell embryos and grow them halfway through pregnancy in an artificial womb.
Bask says when a thylacine is created, the first “thylacine-looking thing” will be born within three to five years, but he “wouldn’t call it a thylacine.” He says researchers are confident of creating the thylacine’s skull, legs and stripes, but there are “things we still don’t know how to do.”
Other scientists are watching with varying degrees of caution and skepticism. Some ask why so much funding and effort goes into restoring species when thousands of them are still alive and on the brink of extinction. Euan Ritchie, professor of wildlife ecology and conservation at Deakin University, says it’s an ambitious project and could lead to breakthroughs that will help conservation. But he says there will be other challenges “when we bring back animals like the thylacine.”
“I think we’ll probably get thylacine-like animals, but they won’t really be thylacines. The question is: What’s next?” He says.
“How would they behave in the wild and what effects might they have on ecosystems? Because there are no living thylacines left, we don’t know how they’re going to behave, and when you bring an animal like a thylacine back, there are no other thylacines to learn from.
“It’s a challenge as big, if not bigger, than the genetic challenge. As an ecologist, it’s the big unknown.
