Could Jurassic Park Really Exist?
In 1990 science fiction writer Michael Crichton published the novel Jurassic Park. The plot follows an eccentric billionaire's attempt to bring dinosaurs back to life for a theme park. The book shot into the bestsellers list and spawned four blockbuster films, a sequel novel and a renewed interest in dinosaurs for a generation. But could it be more than fiction? Could we make real dinosaurs walk among us again? In the novel, Crichton explains the science behind bringing dinosaurs back to life. According to Crichton, insects from the age of the dinosaurs could become trapped in tree resin, which fossilises into amber. This preserves the insects' bodies and DNA. For instance, ants, beetles and wasps have all been preserved in amber. Some of them are over 100 million years old. Some of those ancient insects would be vampiric insects like mosquitos, who drank the blood of prehistoric animals. If they had a meal shortly before they became trapped and then preserved, the blood - and consequently the DNA - of the prehistoric animals they fed on is preserved too. This preserved dinosaur DNA could then be extracted from the insects. However, DNA does degrade over time, and Crichton acknowledges in his book that the DNA would not be perfectly preserved. He suggests that any gaps in the DNA strand could be completed with DNA from modern reptiles and amphibians, who are distant relatives of the dinosaurs. By essentially making dinosaurs instead of breeding them, Crichton says we could engineer their genes to make all dinosaurs unable to breed. Perfect for a prehistoric zoo. The good news is that Crichton's theory for resurrecting dinosaurs is rooted in scientific fact. Amber is an excellent preservative, keeping anything from feathers to frogs intact since prehistory.
Amber found in Lebanon preserved insects that it trapped 130 million years ago. It is quite possible that bloodsucking insects who fed on dinosaurs are preserved. Furthermore, there is nothing wrong with the methods Crichton proposes to bring back dinosaurs. Scientists have successfully extracted and sequenced the genome of a human skeleton that is 430,000 years old. Genetic engineering is well established as a science. And Michael Crichton's suggestion for resurrecting dinosaurs is, in effect, a cloning process. The most famous clone in history to date is Dolly the Sheep, who was brought to life in 1996. Unfortunately, to clone a dinosaur, the raw DNA needs to transform into chromosomes. If this were possible, they would then have to be implanted into an egg for incubation. The egg would have to come either from its own species or from a closely related species. Sadly, no living dinosaur eggs exist - nor do any animals that are sufficiently closely related. But the major obstacle to Crichton's theory becoming reality is DNA itself. DNA decays over time - it's half-life is estimated to be 521 years. This means that, in ideal conditions, DNA could survive for 6.8 million years. Unfortunately, the last dinosaurs walked the Earth around 65 million years ago. What's more, because of its rate of decay, scientists say DNA becomes unreadable after around 1.5 million years, or after one fifth of its lifespan. So to recreate just the most recent dinosaurs, like the velociraptor, Gallimimus or Tyrannosaurus, their DNA would have to survive for 225 million years.
Even if it did, the cloning process would only work if the DNA was preserved in perfect conditions. The ideal conditions for preserving DNA are to have it undisturbed in deep freezing temperatures. Instead, Palaeontologist Jack Horner has proposed another method for creating dinosaurs. It is widely accepted that some dinosaurs evolved into birds. Consequently, birds retain many of the traits of their ancestors. In particular, chicken embryos exhibit many of the physical features of ancient creatures like the archaeopteryx. What prevents chickens from growing into feathered lizards is certain genes. Horner says that by deactivating these genes, we could retro-engineer a ‘dino-chicken'. Already scientists have grown chickens with dinosaur legs, dinosaur feet and a dinosaur beak. None of these animals hatched, but the scientific breakthrough has been made. But in 1992, doctors George Poinar and Raul Cano successfully extracted the DNA from a 125 million-year-old insect, preserved in amber. Since then, further studies suggest that the DNA they extracted was contaminated. It remains unclear just how possible it is to gather and reconstruct ancient DNA. The weight of evidence suggests we can never build Jurassic Park as Michael Crichton envisaged it. It is far more likely that scientists could extract mammoth DNA and incubate its clone in an elephant. In which case, while we might not be able to create Jurassic Park, we could create Pliocene Park. All the same, living, breathing dinosaur-like creatures could exist soon, provided we accept they are really chickens.
Amber found in Lebanon preserved insects that it trapped 130 million years ago. It is quite possible that bloodsucking insects who fed on dinosaurs are preserved. Furthermore, there is nothing wrong with the methods Crichton proposes to bring back dinosaurs. Scientists have successfully extracted and sequenced the genome of a human skeleton that is 430,000 years old. Genetic engineering is well established as a science. And Michael Crichton's suggestion for resurrecting dinosaurs is, in effect, a cloning process. The most famous clone in history to date is Dolly the Sheep, who was brought to life in 1996. Unfortunately, to clone a dinosaur, the raw DNA needs to transform into chromosomes. If this were possible, they would then have to be implanted into an egg for incubation. The egg would have to come either from its own species or from a closely related species. Sadly, no living dinosaur eggs exist - nor do any animals that are sufficiently closely related. But the major obstacle to Crichton's theory becoming reality is DNA itself. DNA decays over time - it's half-life is estimated to be 521 years. This means that, in ideal conditions, DNA could survive for 6.8 million years. Unfortunately, the last dinosaurs walked the Earth around 65 million years ago. What's more, because of its rate of decay, scientists say DNA becomes unreadable after around 1.5 million years, or after one fifth of its lifespan. So to recreate just the most recent dinosaurs, like the velociraptor, Gallimimus or Tyrannosaurus, their DNA would have to survive for 225 million years.
Even if it did, the cloning process would only work if the DNA was preserved in perfect conditions. The ideal conditions for preserving DNA are to have it undisturbed in deep freezing temperatures. Instead, Palaeontologist Jack Horner has proposed another method for creating dinosaurs. It is widely accepted that some dinosaurs evolved into birds. Consequently, birds retain many of the traits of their ancestors. In particular, chicken embryos exhibit many of the physical features of ancient creatures like the archaeopteryx. What prevents chickens from growing into feathered lizards is certain genes. Horner says that by deactivating these genes, we could retro-engineer a ‘dino-chicken'. Already scientists have grown chickens with dinosaur legs, dinosaur feet and a dinosaur beak. None of these animals hatched, but the scientific breakthrough has been made. But in 1992, doctors George Poinar and Raul Cano successfully extracted the DNA from a 125 million-year-old insect, preserved in amber. Since then, further studies suggest that the DNA they extracted was contaminated. It remains unclear just how possible it is to gather and reconstruct ancient DNA. The weight of evidence suggests we can never build Jurassic Park as Michael Crichton envisaged it. It is far more likely that scientists could extract mammoth DNA and incubate its clone in an elephant. In which case, while we might not be able to create Jurassic Park, we could create Pliocene Park. All the same, living, breathing dinosaur-like creatures could exist soon, provided we accept they are really chickens.
Comments
Post a Comment