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- Gameness til the End
Karl Tate, LiveScience Infographic Artist | December 22, 2011 02:49pm ET
Since birds are the only surviving members of the family tree of the dinosaurs, why can’t we flip some switches in the genetic code and return a chicken back to its former glory as a dinosaur?
Interview with Jack Horner – Re-creating a dinosaur
By ZOE BRENNAN
Last updated at 9:51 PM on 13th June 2008
Deep inside the dusty university store room, three scientists struggle to lift a huge fossilised bone.
It is from the leg of a dinosaur.
For many years, this chunky specimen has languished cryptically on a shelf.
Interesting but useless — a forgotten relic of a lost age.
Now, with hammer and chisel poised, the academics from Montana State University in America gather round.
They are about to shatter this rare vestige of the past.
Why would they do such a thing?
Lost age: Scientists now believe it is possible to resurrect the dinosaur after the discovery of DNA relics in the wings and beaks of regular chickens
The answer is that they believe that this single fragment of a beast which stalked the earth untold millions of years ago could hold the key which will unlock the secrets of the dinosaurs.
Extraordinarily, they contend that it could lead to a real life Jurassic Park, where dinosaurs are once again unleashed on the world by scientists.
For just like in the hit Steven Spielberg movie, these men and women are intent on cracking the genetic code of the dinosaurs and opening the possibility of bringing them back to life.
Their remarkable quest will be revealed in a TV documentary, Dinosaurs: Return To Life, to be screened tomorrow.
Critter: In the Jurassic Park story dinosaurs were recreated using genetic code from mosquitos trapped in amber
It poses the question: will scientists ever be able to resurrect the dinosaur?
According to Jack Horner, professor of palaeontology at Montana State University, the answer is an unequivocal yes.
He says: ‘Of course we can bring them back to life. Their ancestral DNA is still present.
‘The science is there. I don’t think there are any barriers, other than the philosophical.’
So just how have these scientists arrived at the point where they believe they might unleash the mysteries of a prehistoric lost world?
In order to understand their journey, we have to travel back a little less time — to 1992.
This was when Raul Cano, professor of microbiology at California Polytechnic State University, made the first attempt to extract DNA from insects almost as old as the dinosaurs that had been embedded in amber, a sticky tree sap which hardens into transparent orange stone.
Speculation about this possibility inspired the Jurassic Park story, in which an amber-trapped mosquito which sucked dinosaur blood unleashes its victims’ genetic code, allowing an obsessed billionaire to clone the species — with terrifying consequences.
In his real-life laboratory, Cano cracked the amber open with freezing cold liquid nitrogen, obtaining a sample of the insect inside.
Amazingly, he soon had a DNA sample from a 40 million-year-old bee.
Soon afterwards, academics at the American Museum of Natural History recovered DNA from an ancient termite.
It seemed that dinosaur DNA could soon be within reach of modern-day scientists.
But these early experiments ended in failure.
The scientists could not replicate their results, leading to the suspicion that the tiny recovered fragments were actually contaminants, perhaps from the researchers’ hair or clothing.
Fossil find: The discovery of the thigh bone of a Tyrannosaurus Rex in Montana, USA, revealed patterns only previously found in the bones of pregnant birds
The search for ancient DNA in amber was abandoned, and it seemed that the door to the past remained closed.
Since then however, researchers looking for prehistoric genetic fragments have managed to recover material from a 40,000-year-old mammoth, and from 45,000-year-old Neanderthal bones.
But still there were doubts that dinosaur DNA could have survived.
Then, in 2003, hopes were revived once again.
Horner, who acted as an advisor on the Jurassic Park films, made a remarkable discovery while his team were excavating a 68 million-year-old Tyrannosaurus Rex skeleton in Montana.
The site was so remote, the skeleton had to be removed by helicopter — the operation led to a huge thighbone splitting in two.
Horner gave a piece of the bone to one of his students, palaeontologist Mary Schweitzer.
Examining it, she noticed a strange structure inside the hard outer case.
It resembled a pattern found only in the bones of pregnant birds.
Experts say they have the ability to reach back to dinosaurs because their blueprints remains locked in modern-day birds
Puzzled, she asked her research assistant, Jennifer Wittmeyer, to dissolve the outer mineral layer.
Six hours later, there was a knock on the door.
‘Jennifer ran into the room saying, “You’re not going to believe this,”’ recalls Schweitzer.
‘When she picked up a small piece, it stretched and moved all over the place.
‘So we knew we had something pretty unusual.’
The magnitude of the discovery was immediately apparent to the Montana University team — the material appeared to be well preserved flesh from a Tyrannosaurus Rex.
Horner says: ‘It’s unimaginable to find soft tissue. It was just assumed that everything had been fossilised.’
More extraordinary yet, was the next find in neighbouring parts of the dinosaur bone.
‘Out popped the blood vessels,’ says Schweitzer.
‘I said, “I don’t believe it, that’s not possible”. It was one of those goose bump moments.’
Horner and his team knew that blood vessels should not exist in fossilised bone.
Many scientists believed organic matter from a living thing could not survive more than 100,000 years — let alone 68 million years.
Next came the team’s attempt to salvage DNA from other bones kept in the university storerooms.
They put the samples they collected under a powerful microscope.
Magnified 4,000 times, tiny structures unlikely to be mineralised fossil material were apparent.
They seemed to be the microscopic cells that built dinosaur bones — called osteocytes.
So far, so good.
But Horner came to believe that his team needed to turn their work on its head if they were to unleash the dinosaur.
Amazing as the discovery of ‘living’ dinosaur tissue was, he feared that constructing a complete DNA map from it would be a never ending task.
So he embarked on a new strategy: retro-engineering a bird.
It is generally accepted by palaeontologists that birds are descended from a class of theropod dinosaurs called raptors.
‘If we want to see a dinosaur in our lifetime, we need to start with a bird and work backwards,’ says Horner.
‘As long as birds exist, we have the ability to reach back to dinosaurs.’
In the 1990s, scientists discovered dinosaurs in China buried in a fine ash.
They were preserved in remarkable detail and bird-like features, including claws and feathers, were recognisable.
Horner believes that a modern bird’s DNA contains a genetic memory that could be ‘switched on’ again, resurrecting long-dormant dinosaur traits.
To make such a creature, he would start with the genome (the whole hereditary information encoded in the DNA) of an emu.
‘Emus have all the features we need in order to make a Velociraptor-sized dinosaur,’ he says.
‘If I were to make a dinosaur, that is where I’d start.’
Far-fetched as this sounds, his work is supported by other leading academics.
Sean Carroll, a geneticist at the University of Wisconsin, says: ‘The inventory of genes in a bird would be very similar to the inventory of genes in a dinosaur.
‘It is differences in the decision-making that takes during development that make the difference between a chicken and a tyrannosaurus.’
Hans Larsson, a palaeontologist at McGill University in Canada, conducted an experiment in November 2007 into the evolution from dinosaurs’ long tails into birds’ short tails more than 150 million years ago.
Looking at a two-day-old chicken embryo, he made an unexpected discovery.
Expecting to see between four and eight vertebrae present in the developing spine, his microscope instead picked out 16 vertebrae — effectively a reptilian tail.
As the embryo developed, the ‘tail’ became shorter and shorter, until the young bird hatched with only five vertebrae.
Larsson says of the significance of the find: ‘For about 150 million years, this kind of a tail has never existed in birds.
‘But they have always carried it deep inside their embryology.’
So, the blueprint for a dinosaur remained locked inside the modern-day bird.
Larsson decided to move from theory to reality.
He wanted to see if he could make a chicken grow a dinosaur’s tail, turning the clock back millions of years.
Manipulating the genetic make-up, he was able to extend the tail by a further three vertebrae.
Larsson had pinpointed a method for turning on dormant dinosaur genes.
If birds retained a dormant tail imprint, did they still retain a memory of dinosaur teeth?
In 2005, Matt Harris and John Fallon, developmental biologists at the University of Wisconsin, noticed something strange while researching mutant chickens.
Harris says: ‘Looking at an embryonic 14-day-old head, I came across the beak and these structures that were not supposed to be there.’
Could they really be teeth? Peeling away the beak in this tiny, mutant bird, the academics revealed sabreshaped formations almost identical to embryonic alligator teeth.
Next, Harris and Fallon attempted to trigger the formation of teeth in a normal chicken, by injecting the embryo with a virus designed to ‘turn on’ the relevant gene.
It was a long shot.
‘Making a tooth is complex,’ says Harris. ‘So the idea of turning on one gene that might be able to do this in an animal that hasn’t made teeth in over 70 million years, was somewhat of a stretch.’
Examining the growing embryo two weeks later, he called colleagues to look at what had happened.
‘You could see very clearly paired structures on the lower jaw.
‘And so, a normal chicken can actually grow teeth.’
This was unexpected. Furthermore, the teeth had the same curved shape as dinosaur
Following this, Harris and Fallon began to find other dinosaur traits in the DNA of birds, such as scales.
They looked at an ancient Chinese breed of chicken called a Silkie.
It has primitive plumage similar to that believed to grow on some dinosaurs.
By activating a dormant gene, Harris and Fallon attempted to ‘trick’ the chicken’s leg into growing feathers instead of scales.
It worked — they had uncovered the genetic changes that had taken place as the dinosaur evolved into a bird.
Meanwhile, in Canada, Larsson had found that the three-fingered dinosaur claw structure remains hidden within a bird’s wing to this day.
‘The dinosaur fingers are adapted for grasping and snatching prey,’ he explains.
‘If we compare this to modern birds, we see the same structures in their wings but adapted for flight.’
With further research, he believes scientists should be able to transform a bird’s wing back into a dinosaur arm.
So, will it one day be possible to reverse evolution?
Mark Westhusin is a world-renowned expert in creating life forms from DNA.
Together with his colleague, Dewey Kramer, at Texas A&M University, he has cloned more species than researchers at any other laboratory, including a White-tailed deer and a Black Angus bull.
Westhusin explains that soon, the relevant DNA to turn back the clock could be manufactured and implanted into an emu egg, for instance, to trigger dormant genes.
‘We already have small artificial chromosomes that have been put into embryos and develop and divide and express their genes,’ he explains.
‘The technology is advancing so fast, in sequencing genes and in putting genes back together, and in manufacturing long stretches of DNA.’
Larsson now believes that in a hundred years or so, geneticists could retro-engineer animals that appear identical to Mesozoic dinosaurs.
‘Why can’t we take all the genetics, just change it around a little bit, and produce a Tyrannosaurus Rex, or something that looks like one?’ he asks.
‘I think that kind of scenario is quite possible. Maybe sooner than we think.’
Fallon agrees, saying: ‘As we learn more, we’ll be able to do it.
‘The genetic knowledge is in the bird.’
For his part, Horner imagines creating the first example.
‘I have to admit that I’ve certainly imagined walking up on a stage to give a talk, and having a little dino chicken walk up behind me,’ he says.
‘That would be kind of cool.
‘There is now nothing to stop us bringing back dinosaurs but ourselves.
‘People who don’t believe it don’t know much about evolution.’
Pausing for a second, he adds: ‘Whether it is a good idea or not is another question…’
Could 2012 be the year of Chickenosaurus, the first dinosaur to live in modern times?
You might recall our story from a few years ago, describing what was then referred to as “Dinochicken.” To recap, Jack Horner, curator of paleontology at the Museum of the Rockies, told me that he and some colleagues were working to create a dinosaur out of a chicken.
The goal is to bring back multiple dinosaur characteristics, such as a tail, teeth and forearms, by changing the levels of regulatory proteins that have evolved to suppress these characteristics in modern birds.
“Birds are dinosaurs, so technically we’re making a dinosaur out of a dinosaur,” Horner explained to me. “The only reason we’re using chickens, instead of some other bird, is that the chicken genome has been mapped, and chickens have already been exhaustively studied.”
The timing of this announcement coincided with the release of Horner’s book, How To Build a Dinosaur: Extinction Doesn’t Have To Be Forever (Dutton Adult, 2009). He suggested to me then that he and some colleagues, such as Hans Larsson of McGill University in Montreal, were already moving forward with the project.
Larsson and his team are analyzing the genes involved in tail development and researching ways of manipulating chicken embryos in order to “awaken the dinosaur within.”
So how far ahead are they with the project now? Horner isn’t revealing, but he continues to share that he and his colleagues are actively working on the needed steps. I think he wants the result to be complete, and not just a chicken with a dino-like tail, for example.
In 1993, Jurassic Park learned a lot from Jack Horner. The Montana State University paleontologist advised Steven Spielberg and crew on the set of the Michael Crichton adaptation on the true behavior of some of the prehistoric era’s most friendly and frightening species. But Horner also learned a lot from Jurassic Park. So much, in fact, that the professor began work on bringing those friendly and frightening species to life off the screen. “The whole idea of making a dinosaur came from [Crichton's] original idea,” Horner tells Hollywood.com. “I kept thinking, ‘There’s got to be a way to do this.’”
So after shooting on the film wrapped, Horner — along with some ambitious graduate students — got to work on recreating a dinosaur. They tried extracting DNA from a Tyrannosaurus Rex specimin, but that turned out to be as helpful as hiding from a Tyrannosaurus Rex in a flimsy bathroom. Instead, almost two decades after Spielberg’s classic screened in theaters, Horner realized the easiest way to bring dinosaurs back to life was to create a dino-chicken. And if you’re thinking that sounds like a chicken that’s been retrofitted to look like a dinosaur, you’d be exactly right.
It’s not as crazy as it sounds. After all, Horner’s process, which involves the paleontologist genetically modifying chicken eggs, is an accelerated form of breeding that targets DNA instead of reproduction. And chickens — along with all birds — are aready equipped with dinosaur DNA, making their eggs the cheapest option for Horner’s experiments. “We really don’t have to do anything because they’re already a kind of a dinosaur,” Horner says. “[But] sixth graders just aren’t happy with that. If you’re going to call it a dinosaur, they want it too look like a dinosaur.”
But how in the name of Dr. Alan Grant — the Jurassic Park paleontologist portrayed by Sam Neill and inspired by Horner — can a chicken look like a dinosaur? It’s not quite a one-step process. Horner’s team is currently working on identifying and reversing the gene that removed the long tail worn by chickens’ prehistoric ancestors, who most resembled the Coelurosauria. Once they do locate the gene for the tail, they’ll move on to three-fingered hands, the mouth, and so forth until “we get something that really does look like an ancient dinosaur,” Horner says. While skeptics might sniff at Horner’s initial 2014 dino-chicken goal date, they should take note: Scientists have already discovered a way to turn on the gene that gives chicken alligator-like teeth. (Still, Horner says “it’s going to be a surprise” exactly when his team does identify the gene.)
Knowing Horner’s goals, it’s easy to wonder if we’ll begin to grow fearful of having chickens in our kitchen. But just as a chihuahua bred from a wolf still barks at bigger dogs, a dino-chicken genetically modified from a chicken will still cluck like a chicken. “It might have to learn how to walk a little, just because it will have an extra something on its back end,” Horner says. “[But while] it will look like a dinosaur, it will just act like a chicken.” (As for ethical questions surrounding Horner’s experiments, the paleontologist says, “Part of the project is to show people that it’s not dangerous and it’s not a bad thing … I’ve never heard anybody say, ‘Well, I don’t know, should we have made a chihuahua?’”)
Which means even if a Jurassic Park is in our future, we shouldn’t expect car trips more exciting than a drive past a farm. Even if the park comes complete with plenty of clever velociraptors. “You’re never going to have the problems you have in Jurassic Park, because animals are not that interested in eating people,” Horner says. “They’re not going to break through buildings or tear holes in your car to get you when they are plenty of other animals around that they don’t have to work so hard for. You only have vengeful dinosaurs and vengeful animals like sharks and stuff in movies.”
Like 2014′s Jurassic Park IV, which has once again recruited Horner as an adviser. And though the paleontologist is remaining mum about the film’s plot details (“It’s going to be a scary movie,” is all he’ll say), perhaps the dinosaurs will look a bit different this time around. After all, in the past 20 years, paleontologists have confirmed that the prehistoric animals were much more plumed than we previously thought.
Not that 1993′s Jurassic Park was exact science. Though Horner did advise production to tweak some details — for example, instead of sniffing at the kitchen door, the warm-blooded velociraptors were supposed to wag their tongue, a trait only exhibited in cold-blooded animals — Spielberg still had to make an entertaining movie. “I sat next to Steven and he would ask questions,” he says. “He would say, ‘What do you think of that?’ And I’d say, ‘Well, I don’t really think they could do that.’ And he say, ‘Well, unless you know for sure, I’m going to do what I want to do.’ Basically, my job was to make sure the dinosaurs looked like they were supposed to look based on the science we had, and he made actors out of them.”
And perhaps if dino-chickens find their way into the spotlight soon, Jurassic Park IV producer Spielberg won’t need to find actors after all.