Colossal, a company focused on de-extinction and species preservation, has made significant strides in its efforts to bring back the thylacine, an iconic Australian marsupial that has been extinct since 1936. The company announced breakthroughs across all stages of the de-extinction process, including advancements in genome sequencing, genetic editing, and assisted reproductive technologies (ART) for marsupials. These achievements not only bring the thylacine closer to revival but also contribute to broader conservation efforts aimed at combating the global extinction crisis.
Breakthrough in Ancient Genome Sequencing
Colossal’s team has generated the most complete ancient genome ever assembled, achieving a level of detail that surpasses previous efforts for any extinct species. The new genome, derived from well-preserved thylacine specimens, is over 99.9% accurate, with only 45 gaps that will be closed through further sequencing. This high level of accuracy, which extends to complex genomic features like centromeres and telomeres, sets a new standard in ancient DNA research.
The genome’s quality is due to the preservation of long DNA sequences in the sample, a rarity for ancient specimens. Additionally, researchers managed to recover long RNA molecules from a 110-year-old thylacine, providing valuable insights into gene expression across various tissues. These achievements are crucial for understanding the thylacine’s biology and facilitating its eventual return to the wild.
Advances in Genetic Engineering
Colossal has made significant progress in identifying genetic features that drive the thylacine’s unique skull morphology. By comparing the genomes of thylacines and canid species (such as wolves), the team identified regions known as “Thylacine Wolf Accelerated Regions” (TWARs), which likely contribute to the morphological similarities between the two groups.
The team demonstrated that these TWARs influence craniofacial development by introducing them into the genomes of transgenic mice and observing changes in skull shape. The successful integration of over 300 genetic edits into the genome of a fat-tailed dunnart—a relative of the thylacine used as a model for de-extinction—marks the most extensive genetic editing performed on an animal cell to date.
Pioneering Assisted Reproductive Technologies
Colossal has also made strides in developing ART for marsupials, a field with little prior research. The company announced two major milestones: inducing ovulation in fat-tailed dunnarts and growing marsupial embryos halfway through pregnancy in an artificial uterus. These techniques are essential for breeding surrogate animals that will eventually carry edited thylacine embryos.
The advancements in ART are not only vital for the thylacine project but also have broader applications in marsupial conservation, such as improving the breeding programs for endangered species like the Tasmanian devil.
Applications for Conservation: Northern Quoll and Beyond
Beyond thylacine de-extinction, Colossal is applying its technologies to other conservation efforts. The company has engineered increased resistance to cane toad toxins in the northern quoll, an endangered Australian marsupial. By making a single edit in the quoll genome, Colossal increased resistance to the toxin by over 6,000 times. Additionally, the team created induced pluripotent stem cell (iPSC) lines for quolls, laying the groundwork for future genetic engineering and biobanking initiatives.
A Path Forward for Conservation
The thylacine de-extinction project is a significant step towards making extinction reversible and using genomic technologies for wildlife conservation. As Colossal continues to develop its technologies, the company aims to not only revive extinct species but also protect endangered ones. With these recent accomplishments, the return of the thylacine to Australia is closer than ever, promising to restore balance to the Tasmanian ecosystem and serve as a model for future conservation efforts.
