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Documentary, PaeoWord S01E11 - Dino Doctors
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00:03The study of dinosaurs has entered a new age.
00:07Predators have now become patients.
00:10High-tech medicine is extracting new clues from ancient bones
00:14and revealing the genetic secrets of dinosaur DNA.
00:20Fossil hunters and physicians have joined forces to become the dino-doctors,
00:25reconstructing the hidden world of the dinosaur.
01:07In this laboratory at the California State Polytechnic Institute,
01:11scientists are reaching back millions of years into the fossil record.
01:17Here, molecular paleontologist Raul Kano is trying to pry loose the genetic code of dinosaurs.
01:23He is one of the world's preeminent experts on ancient DNA.
01:29In the fall of 1992, Kano and his research partner, George Poinar,
01:35extracted and cloned DNA from a 40-million-year-old bee preserved in amber.
01:43Advances like this inspired the blockbuster hit, Jurassic Park.
01:50In the film, scientists create dinosaurs from ancient genetic material, or DNA.
01:58Incredibly, microbiologists may have already achieved one of the key breakthroughs depicted in the film.
02:05If their claims are true, Kano's team has already accomplished the first stage of the Jurassic Park scenario.
02:11From the bone of a Tyrannosaurus rex, they believe they have extracted minute quantities of dinosaur DNA.
02:21The first step has been taken, and we've shown that we can get DNA.
02:26We can get macromolecules out of these things.
02:28I mean, future generations of scientists might be able to improve upon these techniques.
02:34Cloning a dinosaur is still the stuff of fantasy.
02:37Yet other medical advances, such as CAT scans, are giving us tantalizing glimpses of dinosaurs' social habits and their sex
02:46lives.
02:52But, before high-tech analysis begins, fossils must be first unearthed the old-fashioned way,
03:00in a place like Dinosaur Provincial Park in Alberta, Canada.
03:10Here, in one of the world's richest beds of dinosaur bones, paleontologist Darren Tankey excavates fossils for the Royal Tyrell
03:19Museum.
03:22Tankey is a pioneer in the field of paleopathology, a blend of medicine and fossil hunting that's revealing new clues
03:31about dinosaurs from their ailments and injuries.
03:35Yes, definitely pathological. You can tell just from the bone surface texture here.
03:39Life for the dinosaurs had its share of tough breaks. Scattered everywhere, on the surface, are the broken bones of
03:46duck-billed plant eaters.
03:47Today, he has unearthed a hadrosaur bone.
03:51You can tell by the surface texture this bone has undergone a massive bone infection, which can be confirmed by
03:58just looking at the bone in cross-section.
03:59You can see the normal bone here, and then all the new secondary bone growth in response to the infection
04:05has occurred up in here.
04:08Not only does this bone provide evidence of an interesting infection, it sort of provides circumstantial or indirect evidence of
04:16behavior.
04:17A severe leg infection like this one would have made walking difficult and exposed the animal to attack.
04:24But this infection is of such a long-standing time, we can tell that from the thickness of the new
04:30bone on the surface, that this implies that the animal lived quite a long time.
04:35Because the injury had time to heal, Tankey believes this creature was protected, probably as a member of a large
04:43herd of duck-billed dinosaurs.
04:44For the duck-billed dinosaurs, Tankey believes getting bumped and bruised was the price of life in the herd.
04:53Duck-billed dinosaurs show a vast array of injuries, mostly restricted to the tail.
04:58We find injuries from the tip of the tail, which suggests animals accidentally stepped on them.
05:03The middle of the tail, where the vertebrae had been broken in half and then refused back together.
05:08The base of the tail, we found fractures there.
05:11We've got rib cages that show extensive fracturing as well.
05:15This leads me to believe that duck-billed dinosaurs almost certainly were highly accident-prone.
05:22Tankey handles each dinosaur bone with great care, gently wrapping a plaster cast around it for protection.
05:30Then he sends it off for a battery of tests performed by Dr. Bruce Rothschild, a rheumatologist in Youngstown, Ohio.
05:39Rothschild specializes in treating arthritis, but in his spare time he diagnoses dinosaurs.
05:47Together, Rothschild and Tankey represent a new breed of paleontologists, part doctor, part dinosaur hunter.
05:54This collaboration of sciences gives us a new perspective on the lives of the dinosaurs.
06:09Rothschild is especially interested in sauropods.
06:12The family that includes the familiar brontosaurus and diplodocus.
06:17According to one theory on arthritis in humans, when people gain weight they add stress to their knees and hip
06:24joints.
06:24But when he studied the x-rays and CAT scans of sauropods, the heaviest creatures of all, he found no
06:31signs of arthritis.
06:33The fact that it was uncommon in sauropod dinosaurs weighing 60 or 80 tons tells us it can't be purely
06:40a matter of weight.
06:40There has to be another factor.
06:42The hinge joint nature of the weight-bearing joints of dinosaurs did not allow for osteoarthritis.
06:50But the more variable joints of humans, the knee joint of a human, for example, rotating rather than just simply
06:58bending, allows for instability.
07:01And it's that instability that appears to be the cause of the osteoarthritis, so the major factor in its development.
07:08And this is something that dinosaurs were apparently protected from.
07:11The mighty sauropods fossils are found on almost every continent.
07:16The huge plant eaters flourished from about 200 million years ago until their extinction 65 million years ago.
07:23The largest sauropods measured nearly 100 feet long.
07:28Their necks spanned up to 35 feet and they weighed around 70 tons, the equivalent of at least 10 elephants.
07:36They may have eaten as much as 6 tons of vegetation a day.
07:43Once imagined as lethargic swamp dwellers, sauropods are now thought to have migrated over long distances on their sturdy, elephant
07:53-like legs.
07:57When Rothschild examined x-rays of sauropod vertebrae, he noticed that in about half of the samples, a few vertebrae
08:06were fused together, always near the base of the tail.
08:10Humans have a similar adaptation to protect the backbone from stress.
08:15Doctors call this fusion of the backbone DISH, Diffuse Idiopathic Skeletal Hyperostosis.
08:24Rothschild ran the fused dinosaur tailbone through a CAT scanner to see if it resembled DISH in humans.
08:33And it turned out that indeed this fusion that occurs is identical to what we see in humans as DISH.
08:41Now, DISH in humans is a protective phenomenon.
08:43And the question is, why was it occurring in dinosaurs?
08:47Since these fused tailbones were seen in only half the sauropods he studied,
08:52Rothschild reasoned it was a sexual trait, something found either in the males or the females of the species.
09:01He came to the conclusion that it was a female sauropod adaptation.
09:06Their tails were especially strengthened to keep them raised during mating.
09:12But sauropods also had a problem at the opposite end of their huge bodies.
09:18How did Diplodocus manage to support its immense neck without falling over?
09:25The problem was even worse in Mementosaurus, found in China.
09:30At 35 feet long, its neck was more than half the length of its body.
09:34Again, medical technology revealed the answer.
09:39CAT scans of several neck vertebrae of a Diplodocus showed that they were not solid, but riddled with air pockets.
09:48This is really quite impressive.
09:50You can see the individual struts of trabecular patterns within the bones, supporting structures of the bone.
09:56But you notice how much wide open space there is.
10:00The lightweight neck design explains how these enormous dinosaurs were able to remain standing.
10:06Some paleontologists suppose that sauropods graze in the treetops with their heads raised like giraffes,
10:13perhaps even rearing up to reach the topmost foliage.
10:16But University of Pennsylvania paleontologist Peter Dodson proposed another model.
10:22He suggests that sauropods use their necks rather like a vacuum cleaner hose,
10:27standing in one place and reaching round to suck up food.
10:31Consider the possibility that sauropods may have been browsing on ferns on the ground
10:36and that their long neck was just to reach around in a wide swath without doing a lot of moving
10:41around.
10:42Dodson doubts that the sauropod skeleton would have let it raise its head very high.
10:47That they don't have the bone structure in the neck.
10:51They don't have tall spines over the shoulders that would give them the leverage to lift their heads up.
10:58Did they simply rear up on their hind legs?
11:01Dodson doesn't think so.
11:03Their circulatory system could not have handled the enormous blood pressure required to pump blood to the head.
11:09The higher an animal reaches, the higher the vertical separation between the brain and the heart,
11:16the greater the blood pressure is required.
11:19And the longer the neck, the more staggering the blood pressure is required.
11:25And did sauropods suffer blackout when they lifted their heads?
11:29Or did they generate such huge blood pressures that they were in danger of blowing out every capillary in the
11:36body?
11:36Other paleontologists have suggested that since sauropods had very small brains,
11:42they probably didn't require much blood anyway.
11:44If so, they could have easily raised their heads high without bursting a blood vessel.
12:02Perhaps the greatest anatomical mystery is whether dinosaurs were warm-blooded like mammals or cold-blooded like reptiles.
12:11Mammals' bodies maintain a constant temperature, allowing them to be active throughout the day.
12:17Reptiles are active only in the daytime when their body temperatures rise by exposure to the sun.
12:24A hot-blooded dinosaur would be much more active and aggressive than a cold-blooded one.
12:33Indeed, it would behave like an entirely different creature.
12:40Now, a new method of analyzing dinosaur bones has led to a startling conclusion.
12:46Dr. Anousia Chinsami of the University of Pennsylvania is slicing fossil bones into wafer-thin sections
12:54and examining them under the microscope.
12:58She sees similarities to cross-sections of reptile bones, which show annual growth rings, like those of trees.
13:08If you look at a cross-section of a dinosaur bone, you would see very similar rings.
13:12And these rings indicate that dinosaurs are growing fast during the favorable season
13:18and they grow slow during the unfavorable season.
13:21So this is a typical pattern you get in reptilian bone, reptiles which are cold-blooded.
13:27If you look at mammalian bone, on the other hand, or bird bone,
13:31these bones show that the animals are growing very fast without any interruptions in their bone.
13:37So they don't have any growth rings.
13:38So the interesting thing is that the growth of dinosaurs suggests that they have a reptilian characteristics
13:46of a cyclical pattern of growth, but some of them are able to grow fast without any interruptions.
13:52And this kind of pattern seems to indicate that dinosaurs don't just fit into just the reptilian category of cold
14:00-bloodedness
14:01or the mammalian category of warm-bloodedness.
14:03Many paleontologists suspect that metabolism varied greatly from creature to creature.
14:10A predator like Velociraptor, built for speed and agility, may well have been near the warm-blooded end of the
14:18spectrum.
14:19But for a giant sauropod, warm-bloodedness would have been a disaster because its body would have overheated.
14:27In general, the larger the animal, the less desirable warm-bloodedness becomes.
14:36One thermal physiologist came up with the opinion that a warm-blooded sauropod,
14:42that is to say a 30-ton animal, in full sunlight at midday would have suffered meltdown.
14:50So for very large animals, high metabolic rates is probably more of a problem than it is a solution.
14:58Dodson thinks one good model for dinosaur metabolism may be the leatherback turtle.
15:05Weighing up to a thousand pounds, these giant turtles migrate for thousands of miles, passing through frigid Arctic seas.
15:12Though they have a lower metabolism than most mammals, their bodies are large and well insulated,
15:19allowing them to survive in icy waters which would quickly kill a human swimmer.
15:27Another animal with a metabolism halfway between that of a mammal and a reptile
15:32is the nine-foot-long Komodo dragon of Indonesia,
15:37a fearsome-looking beast eerily reminiscent of the dinosaurs.
15:42It takes a long time for a large animal, even without insulation, to lose heat.
15:48So this combination, low metabolic rate and poor thermal conductivity,
15:52guarantees that even an animal with a low metabolic rate will have a warm body temperature.
16:02Experts in wildlife physiology have transformed the thinking about dinosaur metabolism.
16:11Now, modern medical imaging techniques are providing an inside look at dinosaur intelligence.
16:19Tim Rowe, a University of Texas paleontologist, uses CAT scans to create precise 3D maps of the insides of dinosaur
16:29skulls.
16:29Many paleontologists believe birds evolved from dinosaurs.
16:34Rowe examines the contours of their skulls.
16:37He then compares the detailed shapes of dinosaur brains with those of birds.
16:42The goal is to understand how dinosaur intelligence evolved and how it may have differed from that of birds.
16:52By studying the brain, we can get information on sensory systems, coordination, cognitive, associative abilities of dinosaurs and modern birds.
17:02And we can understand in much more detail such things as the evolution of flight, the evolution of intelligence, the
17:08evolution of social interaction,
17:10and particularly sensory modalities like vision and hearing, figure out which were most important to dinosaurs during their history,
17:18and contrast those with some of the other animals living at the same time.
17:26The new techniques are shedding light on dinosaur disease, behavior, and the workings of the brain.
17:33But could biomedical technology really pull off the ultimate feat?
17:38Extracting ancient genes to make a living dinosaur?
17:42The Jurassic Park scenario?
17:46The new science of molecular paleontology has already taken the first steps.
17:52At least two teams of scientists claim to have discovered fragments of dinosaur DNA,
17:58the genetic instructions for making a dinosaur.
18:03In 1992, paleontologist Mary Schweitzer of the Montana State University's Museum of the Rockies
18:09was examining a slice of 65-million-year-old T. rex bone under a microscope.
18:16She noticed something no one had ever seen before.
18:20The blood vessels of the bone appeared to have been preserved along with what looked like red blood cells.
18:26If T. rex blood had lasted all that time, it meant that DNA might also be present.
18:33She sent the specimen to Raul Kano's lab at the California Polytechnic State University.
18:39Kano's team had already extracted ancient DNA from the blood of a 120-million-year-old weevil preserved in amber.
18:47And they claim to have also extracted DNA from the T. rex bone Schweitzer's scent.
18:53But is it really T. rex DNA or the DNA of some contaminating factor?
19:01I could never say I've isolated T. rex DNA.
19:06That's not something we could ever prove.
19:09The only way that anyone could make the claim that they've isolated dinosaur DNA is to grow a dinosaur.
19:15And that is not possible with ancient DNA.
19:18Another team of molecular paleontologists led by Scott Woodward of Brigham Young University recovered DNA from some 80-million-year
19:27-old bones found in a Utah coal mine.
19:30Because the bone fragments are so small, the animal cannot be identified.
19:34When we first saw that dark spot on the gel, it was both very exciting and also kind of scary
19:43because this isn't supposed to happen.
19:47You know, this is 80-million-years-old. There's not supposed to be any DNA.
19:52If these are indeed dinosaur bone fragments, then the findings may truly be dino DNA.
19:59These four rows represent dinosaur sequence, and these four rows represent an Asian elephant sequence across the same portion of
20:07the gene.
20:07If you look real close, you'll notice that they're not very similar, that the patterns are not similar in these
20:13two areas,
20:14which mean that the dinosaur and the Asian elephant were not very closely related.
20:19Remarkably, the recovered DNA bears little or no resemblance to that of any modern animals.
20:26But experts are skeptical. The bones may belong to some other ancient creature.
20:32In theory, researchers could take a strand of dino DNA, plant it in a cell, and then incubate it in
20:39an egg.
20:40The DNA would replicate itself, creating a copy of the creature the DNA came from.
20:49But the idea of hatching a dinosaur is likely to remain science fiction until we know much more about genetics.
20:57The real goal is not to resurrect a dinosaur, but to compare the tiny fragments of DNA already found with
21:06genetic information from other creatures,
21:09including living birds and reptiles.
21:12It would allow us to get more information, not only about organisms that have already become extinct,
21:18but give us information about organisms that are presently living with us.
21:22We can learn about evolution, the rates of mutation, we can learn about how genes change over time.
21:32We may even get some ideas of the condition of the environment in which these organisms lived and died.
21:38If enough DNA could be found, scientists could build up a family tree of dinosaur species.
21:46But the samples of DNA would be so small and the molecular instructions so complex
21:51that paleontologist Peter Dodson is skeptical that will ever happen.
21:57We might make an analogy with an unabridged dictionary, a dictionary that fat,
22:07when the instructions for building an organism represent that much information.
22:12When we find dinosaur DNA, we're just going to find a few fragments.
22:16It's like ripping one page out of that unabridged dictionary and then ripping a strip of paper off that page,
22:22and that's the amount of information we're going to have.
22:25It's going to, pessimistically, I think it's going to tell us nothing.
22:30It's going to be like a parlor trick.
22:34Well, I disagree that any methodology or any strategy that would promote learning is a scishow.
22:42In fact, science is, in the very essence of science, is to learn and to find things that we did
22:49not find before.
22:50It doesn't really specify what is useful and what is not.
22:54Knowledge in itself is useful and valid, and anything that you can get from a dinosaur or from a bacterium
23:01or from a piece of rock that we did not know before is worth doing and knowing.
23:05If recreating an entire dinosaur from its DNA remains an impossible dream,
23:11someday the genetic research may fill crucial gaps in our understanding of dinosaur evolution.
23:18So when we find dinosaur bones, not only might we find dinosaur DNA, but also the microorganisms that probably kill
23:26them,
23:26if they die of an infectious disease.
23:28So that gives us some clues about the evolution of infectious diseases,
23:32and maybe how to treat or how to control modern infectious diseases that affect humans.
23:39Until dinosaur genetics is better understood, paleontologists will continue to dig up new ways to extract the fossil's ancient secrets.
23:50Together with pathologists, the dino doctors will keep applying the latest medical advances to the oldest patients on Earth.
24:29We'll see you next time.
24:39See you next time.
25:03See you next time.
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