ClassX Video Lessons Youtube Channel Curiosity Stream Can We Revive An Extinct Species? | Breakthrough
Imagine a creature that looked like a mix between a wolf and a big cat, with striking stripes on its back. This was the thylacine, also known as the “Tasmanian tiger.” Once roaming freely in Tasmania, the last known thylacine died in 1936 at Hobart Zoo. Dr. Andrew Pask from the University of Melbourne is on a mission to bring this fascinating animal back to life.
The thylacine was a remarkable animal, unlike anything we have today. It was about five feet long and weighed around 70 pounds, similar to a German Shepherd. Despite its tiger-like stripes, it wasn’t related to cats. Instead, it had a dog-like body and carried its young in pouches, much like kangaroos. Sadly, due to drought, hunting, and misconceptions about them preying on sheep, thylacines were hunted to extinction in mainland Australia over a thousand years ago and later in Tasmania.
Many people are captivated by the idea that thylacines might still exist, with frequent sightings reported in Tasmania and mainland Australia. However, scientific surveys using scat samples and hair traps have found no evidence of their survival. It’s more likely that people are mistaking other animals for thylacines.
Dr. Pask, an expert in developmental genetics, has made significant progress by sequencing the entire thylacine genome. His team used DNA from museum specimens collected before the species went extinct. Out of 13 preserved thylacine joeys, only one had DNA preserved well enough for study, thanks to being stored in alcohol.
To understand how thylacines developed, the team conducted CT scans on all verified joeys, creating 3D digital models. They discovered that thylacines started life with typical marsupial features, resembling small pink jellybeans. By 12 weeks, they looked more like dogs or wolves. This research helped pinpoint when the thylacine began to take on its unique form.
Bringing back an extinct species involves more than just cloning. Cloning requires a living cell, but the thylacine’s DNA is just a sequence on a computer. To recreate a living thylacine genome, scientists must edit the DNA of a closely related species. This involves comparing the extinct thylacine’s DNA with that of a living relative and making precise edits using CRISPR technology.
CRISPR allows scientists to make precise edits to DNA. Dr. Pask’s team used this technology to insert a thylacine gene into a mouse embryo, which helped them study skeletal development and understand when thylacines diverged from other mammals. The next step is to modify the genome of a closely related species, like the numbat, to recreate the thylacine’s genetic blueprint.
Despite the challenges, 95% of the DNA sequences that make a species unique are shared between the thylacine and the numbat. The effort to bring back the thylacine is driven by the desire to restore a species that went extinct due to human actions. The ultimate goal is to reintroduce the thylacine to the wild in Tasmania, where its habitat and natural prey still exist.
Apex predators like the thylacine play a crucial role in maintaining ecosystem balance. Their return could help restore Tasmania’s fragile ecosystems. While the journey to revive the thylacine is complex and challenging, it represents a significant step in understanding and potentially reversing human impacts on biodiversity.
Choose an extinct species other than the thylacine and research its history, reasons for extinction, and any efforts to revive it. Prepare a presentation to share your findings with the class, highlighting the similarities and differences with the thylacine’s story.
Participate in a class debate on the ethical implications of using technology to bring back extinct species. Consider the potential benefits and drawbacks, and form arguments for or against the practice of de-extinction.
Engage in a workshop that simulates the use of CRISPR technology. Learn about its applications in genetics and practice designing a simple genetic edit using a virtual CRISPR tool. Discuss how this technology is being used in the quest to revive the thylacine.
Create a 3D model or drawing that illustrates the developmental stages of the thylacine, from a marsupial embryo to its adult form. Use the information from the CT scans and digital models discussed in the article to guide your creation.
Conduct a field study or research project on the role of apex predators in local ecosystems. Analyze how their presence or absence affects biodiversity and ecosystem balance, drawing parallels to the potential impact of reintroducing the thylacine to Tasmania.
Here’s a sanitized version of the provided YouTube transcript:
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[Music] Not long ago, a fierce predator roamed the wilderness of Tasmania: the thylacine. Looking like a cross between a wolf and a big cat, they sported stripes on their backs, which gave rise to the nickname “Tasmanian tiger.” Hunted to extinction on mainland Australia 3,000 years ago, a few survived on the island of Tasmania until the last one died in Hobart Zoo in 1936. Dr. Andrew Pask at the University of Melbourne wants to bring them back.
These were truly amazing and unique animals, unlike anything we currently have on Earth. So, who wouldn’t want to see that? [Music] Drought and Aboriginal hunters caused the thylacine to disappear from the mainland of Australia more than a thousand years ago. The nearby population on the island of Tasmania was also wiped out. It was wrongly believed that thylacines were eating a lot of sheep, leading the Tasmanian government at the time to offer a bounty for people to kill them.
The creature stretched about 5 feet long and weighed around 70 pounds, similar in size to a German Shepherd. They were not related to cats; they had a body shape like a dog but with stripes on their back like a tiger. This is why they are also known as the “mupi” or “wolf.” Like kangaroos, they carried their young in pouches.
The world remains fascinated by this enigmatic predator, with some convinced that thylacines are still alive. Sightings are often reported in Tasmania and even on the mainland. While it would be wonderful to believe that thylacines are still out there, it’s more likely that people are mistaking dogs for them. Scientists have conducted numerous surveys using scat samples and hair traps across Tasmania, but no physical evidence of thylacines has been found.
Dr. Pask is an expert in developmental genetics, focusing on how genes in our genome contribute to the characteristics of an animal. His team made a significant breakthrough by sequencing the entire thylacine genome. They obtained thylacine DNA from museum specimens collected before the species went extinct. Although there were supposedly 13 preserved thylacine joeys worldwide, Dr. Pask discovered that two were actually Tasmanian devils, and ten of the genuine thylacines were preserved in formalin, which destroys DNA. However, the 11th specimen, a 4-week-old joey taken from its deceased mother’s pouch in 1909, had been stored in alcohol, which preserved the DNA well.
Before moving forward with their DNA samples, the team needed to understand how thylacines developed after birth. They conducted CT scans on all 11 verified joeys worldwide to create 3D digital models. They aimed to determine when during the creature’s development it began to resemble a wolf. Using a technique called micro-CT, they were able to visualize the internal structure of the specimens.
The data was used to construct three-dimensional images, revealing that the joeys started off with typical marsupial features. At birth, they resembled small pink jellybeans with strong front limbs to crawl into their mother’s pouch. By around 12 weeks old, they left the pouch and looked more like dogs or wolves, with longer hind limbs.
The team wanted to identify the exact stage when the developing thylacine began to take on a dog-like appearance. They discovered that the changes occurred later in development than initially expected. The scientists now understood how thylacines physically developed after birth, but they also needed to investigate the role of DNA in this process.
By isolating specific genes from the DNA, they aimed to understand how the thylacine evolved its unique body form. The DNA from the Melbourne specimen was sufficient to recreate the entire genome of the thylacine. However, bringing an extinct animal back to life is different from cloning. Cloning requires starting with a living cell, while the thylacine DNA is just a sequence on a computer screen.
To create a living thylacine genome, scientists would need to edit the DNA of a closely related species. They would compare the DNA of the extinct thylacine with that of its living relative and make precise edits to recreate the thylacine’s genetic blueprint. This process involves millions of edits, each needing to be checked for accuracy.
Using CRISPR technology, they can make these edits. After identifying and editing the thylacine gene that creates bone, they inserted it into a mouse embryo, tagging the gene to glow blue when active. This allowed them to study the development of the mouse skeleton and understand when thylacines diverged from other mammals.
The next step in Dr. Pask’s journey is to create a living thylacine genome by modifying the genome of a closely related species. He believes that the numbat, a close living relative of the thylacine, might provide a good starting DNA blueprint. However, there are significant differences between their genomes, making the task more challenging.
Despite the challenges, 95% of the DNA sequences that make a species unique are shared between the thylacine and the numbat. The effort to bring back the thylacine is driven by the desire to restore a species that went extinct due to human actions. The Tasmanian tiger’s modern relatives are also in danger, and efforts to protect and preserve them are crucial.
The ultimate goal of this de-extinction effort is to reintroduce the thylacine to the wild reserves in Tasmania. The habitat and natural prey for the thylacine still exist, making it a viable candidate for reintroduction. Apex predators like the thylacine are essential for maintaining ecosystem balance, and their return could help restore Tasmania’s fragile ecosystems.
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Thylacine – A carnivorous marsupial native to Tasmania, now believed to be extinct. – The thylacine, also known as the Tasmanian tiger, was the largest known carnivorous marsupial of modern times.
Extinction – The process by which a species, genus, or family ceases to exist. – The extinction of the dodo bird is often cited as a classic example of how human activity can lead to the loss of a species.
Genetics – The study of heredity and the variation of inherited characteristics. – Advances in genetics have allowed scientists to better understand the mechanisms of evolution and inheritance.
DNA – Deoxyribonucleic acid, a self-replicating material that is the carrier of genetic information in all living organisms. – DNA sequencing has revolutionized the field of biology by providing insights into the genetic makeup of organisms.
Cloning – The process of producing similar populations of genetically identical individuals. – Cloning has been used in agriculture to produce plants with desirable traits.
Marsupial – A type of mammal characterized by giving birth to relatively undeveloped young, which are typically carried and suckled in a pouch on the mother’s belly. – The kangaroo is a well-known example of a marsupial, with its young developing in a pouch.
Ecosystem – A biological community of interacting organisms and their physical environment. – The Amazon rainforest is a vast ecosystem that supports a diverse range of plant and animal life.
Biodiversity – The variety of life in the world or in a particular habitat or ecosystem. – Protecting biodiversity is crucial for maintaining the health and stability of ecosystems.
CRISPR – A technology that can be used to edit genes and has the potential to correct genetic defects. – CRISPR technology has opened new possibilities for treating genetic disorders by allowing precise modifications to DNA.
Predator – An animal that naturally preys on others for food. – In a balanced ecosystem, predators play a crucial role in controlling the population of prey species.
