The Genetic Blueprint
The scientific effort to return the thylacine (Thylacinus cynocephalus) to Tasmania hinges on genetic material from long-dead animals. In a significant step, researchers successfully extracted RNA from the skin and muscle of a 130-year-old thylacine specimen preserved at room temperature in a museum collection. RNA, the molecule that translates DNA's instructions into cellular functions, provides a deeper understanding of the animal's biology beyond what its DNA sequence alone shows. This work helps to create a more complete and accurate map of the thylacine genome.
The project is a collaboration between the biotechnology company Colossal Biosciences and the University of Melbourne's Thylacine Integrated Genomic Restoration Research (TIGRR) Lab. Scientists have now reconstructed a thylacine genome that is over 99.9% complete, making it one of the most complete ancient genomes for any species. This high-quality genetic blueprint, approximately 3 billion base pairs in length, is the foundational tool for the de-extinction attempt. The last known thylacine died in captivity in Hobart's Beaumaris Zoo on September 7, 1936.
From Code to Creature
The path from a genetic sequence to a living animal involves advanced reproductive technologies. The plan uses the genome of the thylacine's closest living relative, the fat-tailed dunnart (Sminthopsis crassicaudata), as a template. The dunnart is a small, mouse-like carnivorous marsupial. Using CRISPR gene-editing technology, scientists modify dunnart cells, altering their DNA to match the thylacine blueprint. The team has already edited over 300 unique genetic changes into a single dunnart cell line.
Once a cell nucleus contains the edited thylacine DNA, it will be transferred into a dunnart egg to create an embryo. This embryo will then be carried by a dunnart surrogate mother. Researchers are developing assisted reproductive technologies (ART) specifically for marsupials to make this possible. This includes methods to induce and control ovulation in dunnarts, an important step for creating embryos for the project. The goal is to reintroduce the thylacine to its native habitat in Tasmania.