Bringing back the past to protect the future | Andrew Pask | TEDxSydney

Key Concepts:

• De-extinction: The process of bringing extinct species back to life using genetic technologies.
• Apex Predator: A predator at the top of a food chain, playing a crucial role in ecosystem health.
• Ecosystem Collapse: The degradation and destabilization of an ecosystem due to the loss of key species or environmental changes.
• Genome Sequencing: Determining the complete DNA sequence of an organism.
• Genetic Engineering: Modifying an organism's genes using biotechnology.
• Cane Toad Toxin Resistance: The ability of an animal to withstand the toxic effects of cane toads.

1. The Biodiversity Crisis and Extinction Rates

• The planet has lost 2/3 of its wildlife in the last 50 years.
• The Earth is experiencing its sixth mass extinction event, caused by human activities.
• Australia has the highest rate of mammal extinctions globally.
• Species like the spotted qual, mountain pygmy possum, and hairy-nosed wombat are predicted to go extinct within the next 10 years due to human impacts.
• Examples of already extinct species include the pig-footed bandicoot and the Tasmanian tiger (thylacine).

2. The Importance of Apex Predators: The Case of the Tasmanian Tiger

• The Tasmanian tiger was a unique marsupial apex predator, crucial for its ecosystem.
• Its extinction on September 7, 1936 (World Extinction Day) had devastating consequences.
• Apex predators are vital for maintaining ecosystem balance, controlling populations, and preventing disease spread.
• The removal of wolves from Yellowstone National Park in 1926 led to ecosystem collapse: deer overpopulation, vegetation loss, land erosion, and river changes.
• Reintroduction of wolves in 1995 restored the ecosystem within 10 years, demonstrating the power of apex predators to engineer landscapes.
• Tasmania is experiencing similar issues with kangaroo and wallaby overpopulation due to the absence of the Tasmanian tiger.
• The Tasmanian devil population is threatened by devil facial tumor disease (DFTD) because the absence of an apex predator allows diseased animals to persist and spread the disease.

3. De-extinction Science: Reversing Extinction

• De-extinction science aims to reverse extinction using genetic technologies.
• The process involves sequencing the entire genome of the extinct species from museum specimens.
• The genome is then compared to the closest living relative (e.g., the fat-tailed dunnart for the Tasmanian tiger).
• Genetic engineering is used to edit the dunnart's DNA to match the Tasmanian tiger's DNA (only 0.1% difference).
• Cloning technologies, similar to those used for Dolly the sheep, can then be used to create a living Tasmanian tiger from the re-engineered cell.
• Marsupials give birth to very small young, so a dunnart can act as a surrogate mother for a Tasmanian tiger.

4. Applications of De-extinction: Cane Toad Toxin Resistance

• De-extinction science can also be used to enhance the resilience of endangered species.
• The northern quoll is threatened by toxic cane toads.
• Animals in South America that evolved alongside cane toads have a natural resistance to the toxin.
• Scientists have identified the specific gene responsible for cane toad toxin resistance.
• They have engineered quoll cells with this gene, making them resistant to cane toads.
• The goal is to create live cane toad toxin-resistant quolls, which can then help control the cane toad population.

5. Conclusion

• De-extinction science is a crucial tool for addressing the biodiversity crisis and undoing past environmental mistakes.
• It involves using genetic technologies to bring back extinct species and enhance the resilience of endangered species.
• By embracing de-extinction, we can learn from the past and rebuild a healthier future for the planet.