Genetics Company Plans to Bring Extinct Tasmanian Tiger to Life, Will It Work?

The genetics company Colossal Biosciences, based in Dallas and working to bring back the woolly mammoth, has announced that they have begun efforts to bring back the Tasmanian tiger, also known as the thylacine.

Before going extinct, Tasmanian tigers, which were indigenous to New Guinea, Tasmania, and the Australian mainland, first emerged around 4 million years ago. The species was the world's largest carnivorous marsupial that lived at the time.

According to the Australian Museum, thylacine, one of Australia's most famous species, went extinct on the mainland at least 2,000 years ago as a result of a sharp decline in its population and possible human hunting and dingo competition.

Tasmanian Tiger

Although it was declared extinct on 1982, the last known thylacine died in captivity in 1936. European settlers, who considered it a pest, probably played a key role in its decline. Several unconfirmed sightings have been reported over the course of the 20th and 21st centuries.

De-Extinction and Reintroduction to Nature

A company is planning to create a genetically-modified hybrid of the thylacine and the Tasmanian tiger. They hope to reintroduce the animals to selected areas in Australia with the hopes that it will have a positive impact on local ecosystems. Colossal, which was founded by tech entrepreneur Ben Lamm and Harvard geneticist George Church, is also working on a woolly mammoth project.

Balancing the Ecosystem

Reintroducing the thylacine proxy, according to Colossal, will restore ecosystem balance to areas that have experienced biodiversity loss as well as ecosystem degradation since the extinction of the top predator and keystone species. The Tasmanian tiger once had a strong influence on the balance of the ecosystem because it preyed on non-native intermediate predators that hunted native herbivores.

Colossal has teamed up with the University of Melbourne's Thylacine Integrated Genetic Restoration Research Lab (TIGRR) to pursue de-extinction projects. TIGRR is headed by Andrew Pask, a leading marsupial evolutionary biologist, and Tasmanian tiger expert, who has already sequenced most of the animal's genome. Lamm said that from a Colossal perspective, they are interested in pursuing projects where the reintroduction of the restored species can fill an ecological void that was created when the species went extinct.

The thylacine was the inspiration for the Tasmanian tiger moniker. It was unrelated to tigers and wolves but had certain characteristics that are similar to both. Its large head made it almost dog- or wolf-like, which is why it has been called a Tasmanian wolf.

The thylacine was a marsupial apex predator that lived in modern times. It was crucial to Tasmania's ecosystem, and its loss had a significant effect.

Tasmanian Devil Facial Tumor Disease

According to Pask, one illustration of this is the emergence of the fatal Tasmanian devil facial tumor disease, which illustrates what can occur when sick animals are no longer preyed upon and eliminated from the population.

Thylacines could have prevented the Tasmanian devil from going extinct and would have assisted in limiting the spread of this deadly disease in Tasmania. Pask claims that since the thylacine only recently went extinct, there is a greater chance that de-extinction efforts will be successful.

Read also: Scientists Map DNA, Genome Sequence to Potentially Resurrect Extinct Tasmanian Tigers 

Next Best Thing: Closest to the Extinct Species

Scientists have completed the sequencing of around 96% of the thylacine genome, but more work remains to nail down the remaining 4%. The goal of any de-extinction project is to create an extinct animal as close as possible by altering the genome of live cells from that animal's closest living relative. Like the woolly mammoth project, this project will involve the use of advanced gene-editing technologies.

One of the key resources for their work is a good genome from your extinct species, and they are using samples from museum collections to help them build a blueprint of this ancient creature.

After comparing the genomes of the two, they will decide which is more closely related to each other. The edited genome will then be inserted into stem cells that can be prompted to turn into embryos that can form whole animals.

The team of scientists is trying to develop a womb that can grow an embryo from conception to birth. Either a surrogate mother will be used to carry the embryo to term, or a synthetic marsupial womb, which has not yet been created, will. One of the amazing things about marsupials is that they all have tiny, rice-grain-sized offspring, which means that even a dunnart the size of a mouse could give birth to a Tasmanian tiger cub, Newsweek reports.

Related article: Tasmanian Tiger Revival from Extinction: Now Possible -Study