The dinosaurs that once ruled the earth for 160 million years suffered a mass extinction in the Cretaceous period about 65 million years ago, and today it is basically impossible to see real living dinosaurs.
However, in the United States there is a science madman who is preparing to resurrect dinosaurs.
The method by which this madman resurrected the dinosaurs initially looks strange, but if you look closely, you will find that the method he uses is scientifically reasonable.
Using advanced life technology, is it really possible for dinosaurs to be resurrected? Today Aaron will take you to see this real scientific story.
<h1 class="pgc-h-arrow-right" data-track="8" > a broken T. rex thigh bone</h1>
Fast back in 2003, in a wasteland in northeastern Montana, a fossil of a Tyrannosaurus rex was discovered and excavated by local paleontologists.
Scientists named it B-Rex, and by looking at the growth lines in the bones, scientists estimated its lifespan to be about 16 years.
The fossils of the T. rex are not complete, with a total of 111 bones, but because the excavation site is so remote, scientists have to use helicopters to separate the fossil bones.
During the transport, a 0.9-meter-long thigh bone suddenly broke.
This unexpected rupture led to a major scientific discovery that would later occur.
The head of the excavation project at the time was Jack Horner, a well-known expert in paleontology and a dinosaur maniac who had discovered and excavated many dinosaur fossils.
He also served as a technical consultant in the Jurassic Park film series, and the male protagonist in episodes 1 and 3 of the film is also based on the paleontologist who excavated dinosaurs.
After the Tyrannosaurus rex's thigh bone was broken, Horner carefully collected the fallen bone fragments and sent them to one of his students, Mary Schweitzer.
The Schweitzer, a paleontologist at North Carolina State University, analyzed bone fragments and found something she had never seen before.
Some medullary tissue was magically seen on these 68 million-year-old bone slices.
This medullary tissue is special, it only exists in female birds, what is it used for?
When female birds are about to lay eggs, the medullary tissue is converted into calcium and eventually into the shell of the bird's egg.
Hey, that's interesting.
The discovery of medullary tissue used to lay eggs in the bones of Tyrannosaurus rex can illustrate at least two points:
1. This Tyrannosaurus rex is female and pregnant.
2. Tyrannosaurus rex has a certain affinity with modern birds.
The discovery shocked the scientific community at the time, but the story wasn't over.
<h1 class="pgc-h-arrow-right" data-track="18" > mystery collagen</h1>
By 2004, Schweitzer felt that the bone fragments of the Tyrannosaurus rex had little research value, and she asked her assistant to put a bone fragment into a weak acid solution so that the petrified bone would be completely decomposed, but strange things happened again.
After a long soak, the bone is thoroughly broken down, but eventually leaves a resilient substance.
It is quite rare to find such things in fossilized bones from tens of millions of years ago.
Schweitzer looked at it with a high-power microscope and found that there was something round here, which looked like red blood cells and had blood vessels distributed on them.
At this point, Schweitzer was startled by what he saw in front of him, was it the blood tissue of the Tyrannosaurus rex?
If it is really the blood tissue of Tyrannosaurus rex, it is the oldest blood in the world, which probably contains the DNA of Tyrannosaurus rex, and with the DNA of Tyrannosaurus rex, it is possible for humans to crack the genetic code in it and possibly clone a living Tyrannosaurus rex.
Is the jurassic park scene really going to become a reality?
Later, Schweitzer discovered that all that was left in the weak acid solution was some soft tissue of T. rex, and although it contained elastic blood vessels and bone cells, it could not extract the DNA of T. rex.
Because even under low temperature and sterile conditions, the usable lifespan of DNA can be extended to millions of years at most, and the Tyrannosaurus rex died about 68 million years ago, and the DNA in its body has already degraded.
But Schweitzer has a paleontologist's acumen, and she firmly believes that there must be other hidden secrets in these soft tissues.
Schweitzer and her mentor Jack Horner speculated that the Tyrannosaurus rex fossil would quickly break down the soft tissue within the bones during excavation and transportation.
In order to obtain higher quality soft tissue samples, they built a mobile laboratory with a container truck and drove the laboratory directly to the excavation site.
Soon, they got better samples from freshly baked Tyrannosaurus rex fossils.
Schweitzer separated the soft tissues from the bones and ground them into powder, wrapped in dry ice and sent them to her former colleague John Asara.
Asara, a researcher at Harvard Medical School, wanted Assara to perform more sensitive differential analyses of the soft tissues of T. rex.
Through a technique called mass spectrometry, Asara discovered that the bone soft tissues of Tyrannosaurus rex contained 7 collagen proteins, and the sequences of these proteins were also measured and read.
Then Asara compared the protein sequence of the Tyrannosaurus rex with the protein sequence of 21 modern animals, and it was not better than that, which made a surprising discovery!
The collagen sequence of the Tyrannosaurus rex is very similar to the collagen sequence of chickens, and the protein sequence of other animals is far from the difference.
What does this mean?
This shows that Tyrannosaurus rex and chicken have a fairly close relationship.
In the eyes of most people, this major discovery is indeed a bit ruined, and even some media have exaggerated reports that chickens are the descendants of Tyrannosaurus rex.
In fact, combined with the existing scientific evidence, the evolutionary relationship between Tyrannosaurus rex and chickens is roughly like this.
Both Tyrannosaurus rex and chickens have a common ancestor: theropod dinosaurs, which appeared about 200 million years ago and were the first large carnivores on Earth.
Then, theropod dinosaurs continued to evolve the dinosaurs of the styropods, ornithopods, virtual bone dragons, and tyrannosaurs, and you can see that to the tyrannosaurs, it is the closest common ancestor of tyrannosaurus rex and chickens.
Then the Tyrannosaurus rex evolved two types of dinosaurs, and Tyrannosaurus rex and chickens have since parted ways.
In the Tyrannosaurus rex branch, first the Tyrannosaurus rex superfamily, followed by the T. rex family, and the T. rex is the most typical species in this family.
In the chicken branch, mainly hand robbers, under the hand robbers there is a class called oviraptorosaurs, according to the fossils currently unearthed, oviraptorosaurs have begun to look a bit like birds, their mouths are similar to parrots, and sharp teeth can no longer be seen in the mouth.
Under the true hand robbers, ornithischian dinosaurs began to evolve, and the ornithopod dinosaurs included Archaeopteryx and Proximodyosaurus underneath.
Based on the evidence scientists have found so far, it is likely that Archaeopteryx and Archaeopteryx eventually evolved into the birds we see today, and the chicken we most commonly see is actually a bird.
Judging from this evolutionary tree, chickens are descendants of dinosaurs.
Although today's chickens have no sharp teeth and have lost the huge claws of their ancient ancestors, deep in the DNA of chickens, they still retain the terrifying and fierce blood of the dinosaur ancestors.
Dinosaur maniac Jack Horner believed that there was a genetic map of dinosaurs hidden in the DNA of chickens, so he proposed a crazy research plan: to resurrect dinosaurs with chicken DNA, so as to get a completely new species: chicken dragons.
Will he be able to succeed? Let's move on.
<h1 class="pgc-h-arrow-right" > decipher the chicken code</h1>
Let's go back to 2004, when Schweitzer's assistant at North Carolina State University threw the Tyrannosaurus rex bone into a weak acid solution, another university in the United States, the University of Washington, was conducting a research project on chickens: the Red Chicken Genome Sequencing Project, which aims to unlock the entire genetic code of chickens.
The red original chicken, the subject of the study in this plan, has been previously considered by scientists to be the ancestor of all modern domestic chickens.
Scientists from the Beijing Genomics Institute of the Chinese Academy of Sciences, after learning of the plan, put forward an idea at the time, saying:
It is good to determine the genetic code of chickens, but you can't just measure the ancestors of chickens, and the offspring of chickens should also be measured together.
As a result, broiler chickens from Britain, layer chickens from Sweden, and black chickens unique to China have come to the scene and become the object of measurement.
Soon, scientists deciphered the genetic code of the four chicken breeds.
Later, the genetic code of more chicken breeds was also deciphered, and the functions of some of these genes were gradually discovered and verified.
For example, a gene called TSHR mutated in chickens, which led to chickens being able to lay eggs all year round.
Another example is a gene called TBC1D1, which is mainly responsible for the regulation of sugar metabolism, and if this gene has an important mutation, it is likely to make the chicken grow a fat body and become a "big fat chicken".
The deciphering of the chicken's genetic code laid a solid scientific foundation for Jack Horner's crazy plan to resurrect dinosaurs with chicken DNA.
Jack Horner felt the time was ripe and he was ready to go.
<h1 class="pgc-h-arrow-right" > create chicken dragons</h1>
If you put the skeletons of chickens and dinosaurs together, you will find that there are many similarities between them.
For example, they all have three phalanges, similar iliac bones, and similar neck vertebrae.
But there are also some notable differences between the two.
Dinosaurs had long tails, while chicken tails had degenerated, leaving only tail bones.
Dinosaurs' original arms and claws evolved into chickens and have become wings.
Dinosaurs had sharp teeth, while chickens had no teeth, replaced by beaks commonly found in birds.
Behind all these similarities and differences is controlled by genes.
Horner believes that chicken DNA may still retain all the genes that control traits such as dinosaur tails, arms and teeth, but they have lost their activity after millions of years of evolution.
If these genes can be reactivated during the embryonic development stage, the chick hatched from the egg is likely to look like a small dinosaur.
Horner's speculation is full of imagination, but is that really the case? Let's move on.
< h1 class= "pgc-h-arrow-right" > silencing ancient gene</h1>
In 2005, Matthew Harris, a developmental biologist at the University of Wisconsin, was conducting a routine experiment.
His subjects were chicken embryos, but not ordinary chicken embryos.
Harris's chicken embryos carry a genetic mutation called TALPID2, which affects the normal development of chicken embryos, which die within 18 days of hatching.
Originally a very conventional embryo observation experiment, an unusual phenomenon occurred.
One night, Harris was working overtime in the lab, and he was examining the head of a 16-day-old chicken embryo when he stumbled upon some tiny protrusions at the edges of the chicken's beak, a structure Harris had never seen before.
Surprised, Harris then dissected the head of the chicken embryo and found teeth growing on the edge of the chicken's beak.
Although the teeth are still small, they are already visible as conical saber teeth that look like dinosaur teeth.
Later, scientists from Yale and Harvard university also changed the genes associated with the development of chicken embryos, so that the chickens grew a pair of round noses that had not yet fused, which looked close to the noses of crocodiles and dinosaurs.
The results of these experiments shocked the scientific community at the time, and also confirmed Horner's speculation: the chickens did retain the ancient genes of ancient ancestors, and under certain conditions, these ancient genes could be activated.
Subsequently, Horner and his research team began experiments with the real creation of chicken dinosaurs.
They injected the chicken embryos with a virus that carries genes that control tail growth, as well as a small section of alligator's tail gene switch, which they hope to transfer into will activate the already silent tail gene in the chick and make the chick grow its tail.
The same principle applies to the generation of chick arms. In the early stages of chicken embryonic development, it is actually possible to observe the arm with three fingers, but in the later stages of development, these three fingers will fuse together and eventually become the wings of the chicken.
But if the transfer of foreign genes inactivates the genes that control the fusion of chicken fingers, and activates the genes that develop the arms, it is possible to see chicks with arms and claws. Oh no, it should be a chicken dragon.
Although so far we haven't seen the really alive chick dragons born, looking at this prototype, someone has fidgeted.
<h1 class="pgc-h-arrow-right" > Chicken Dragon=Monster? </h1>
By genetically modifying chickens to create chicks, Horner believes it is entirely possible in scientific principles to achieve this.
However, for this crazy research project, the outside world does not agree.
Some scientists criticized Horner, saying that even if his project was successful, he would only get a monster chicken.
Horner responded to such criticisms.
He admits that by genetically modifying chickens, it is never possible to get a real dinosaur.
However, he hopes that through such research projects, people can better understand the evolutionary process from dinosaurs to birds, while promoting the development of developmental biology and medicine.
For example, to study how the tail of an animal develops and grows, for our human lumbar disc herniation, there may be a better prevention and treatment plan?
Some people say that by the time the chicks are actually born, humans can have a different kind of pet again.
Do you think it's reliable to make dinosaurs from chickens? If it was really built, would you be willing to keep a chicken dragon as a pet? Feel free to share your thoughts in the comments section.
I am Aaron of the biosphere, thank you for your patience in reading.
Follow me and take you to learn more about the wonderful life sciences and stories, we will have a period later.