Nearly 100 years after extinction, the Tasmanian wolf may live again. Scientists want to resurrect the striped, carnivorous marsupials, officially known as thylacines, that used to roam the Australian bush.
The project will use scientific advances in genetics, the restoration of ancient DNA and artificial reproduction to resurrect the animal.
“Firstly, we are strongly in favor of protecting our biodiversity from further extinction, but unfortunately we are not seeing a slowdown in species extinction,” said Andrew Pask, professor at the University of Melbourne and director of his Thylacine Comprehensive Research Laboratory. Genetic restoration leading the initiative.
“This technology provides an opportunity to correct this problem and can be applied in exceptional circumstances when the main species have been lost,” he added.
The project is a collaboration with Colossal Biosciences, founded by technology entrepreneur Ben Lamm and George Church, a geneticist at Harvard Medical School. This company is working on an equally ambitious, perhaps more daring, $15 million project to bring back the woolly mammoth in a shapeshifting form.
The coyote-sized thylacine disappeared about 2,000 years ago worldwide except for the Australian island of Tasmania. As the only modern carnivorous marsupial predator, it has played a key role in its ecosystem, although this has made it unpopular with humans.
European settlers on the island in the 19th century blamed the loss of livestock on the thylacines (although mishandling of wild dogs and human habitats is to blame in most cases) and hunted Tasmania’s shy, midnight wolves until they disappeared.
The last thylacine to live in captivity, named Benjamin, died after being exposed to a rare extreme weather event in 1936 at Beaumaris Zoo in Hobart, Tasmania.
genetic blueprint
The project consists of several complex phases that involve cutting-edge science and technology, such as gene editing and the creation of artificial queens.
First, the team will create a detailed genome of an extinct animal and compare it to that of its closest living relative to reveal differences, namely a mouse-sized carnivorous marsupial called the fat-tailed dunnart.
“Then we take living cells from our dunnart and change its DNA in all the places where it differs from thylacine. Basically, we are designing a dunnart cage to become a Tasmanian wolf cage,” Pask explained.
Pask said that after the team has successfully programmed the cell, stem cells and reproductive technologies that include Dunnarts as surrogates “turn that cell back into a living animal.”
“Our ultimate goal with this technology is to return these species to the wild, where they played an absolutely important role in the ecosystem. So our main hope is that one day we will see them again in the bush of Tasmania,” he said.
The fat-tailed dunnart is much smaller than the adult Tasmanian wolf, but Pask noticed that all marsupials give birth to tiny babies, sometimes the size of a grain of rice. This means that a mouse-sized marsupial could serve as a surrogate belly for a much larger adult animal like the thylacine, at least in the early stages.
Pask added that reverting the thylacine to his old habit would have to be done very carefully.
“Any release of this nature requires analysis of the animal and its interactions in the ecosystem over many seasons and over large areas of closed terrain before a full reconstruction can be considered,” he said.
The team has yet to set a timeline for the project, but Lamm said he believes progress will be faster than efforts to bring back the woolly mammoth, noting that elephants take much longer to gestate than dunnarts.
These techniques may also help other marsupials avoid the fate of the thylacine, such as the Tasmanian devil, which is threatened by wildfires as a result of the climate crisis.
“The technologies we are developing to resurrect the thylacine have all the immediate conservation benefits for protecting marsupials. Biobanks of frozen tissue from living marsupial populations were collected to protect against fires,” Pask said.
“However, we don’t yet have the technology to harvest this tissue, create marsupial stem cells, and then turn those cells into a living animal. This is the technology we are going to develop as part of this project.”
hybrid animals
However, the way forward is non-linear and unclear. Tom Gilbert, professor at the GLOBE Institute at the University of Copenhagen, said resurrection of extinct animals has serious limitations.
Recreating the complete genome of an extinct animal from DNA found in ancient skeletons is a big challenge, meaning it will be missing some genetic information, explained Gilbert, who is also director of the Center for Evolutionary Hologenomics at the Danish National Research Foundation.
In turn, Gilbert studied the resurrection of the Christmas Island Mouse, also known as the Maclear Mouse, but is not involved in the project. The team will not be able to accurately recreate the thylacine, but will instead create a hybrid animal, a modified form of the thylacine.
“It is unlikely that we will be able to obtain the complete genome sequence of an extinct species, so we will never be able to completely recreate the genome of an extinct species. There will always be some parts that cannot be changed,” Gilbert said. .
“They will have to choose what changes they have to make. Therefore the result will be
hybrid”.
Perhaps, he said, a genetically deficient thylacine hybrid might be in poor health and not survive without a lot of help from humans. Other experts question the very idea of spending tens of millions of dollars on resurrection attempts when so many living animals are on the brink of extinction.
“For me, the real advantage of any project like this is its greatness. It seems to me that this is very justified simply because it will arouse people’s interest in science, nature and conservation, ”said Gilbert.
“And we really need this awakening in our world if we are going to survive in the future. But… do the parties concerned understand that they will receive not a thylacine, but an imperfect hybrid? What are we doing? I don’t need more frustrated people” or feeling cheated by science.”
