At present, scientists believe that organic molecules in fossils cannot be preserved after more than 654.38 million years. Schwaetzer hopes to do further research to accurately reveal the composition of soft tissues separated from these fossil bones. If these soft tissues are made of organic cells, then genetic information is still preserved in these cells? Schwaetzer said that if protein could be extracted from these substances, scientists might know the details of dinosaur life.
In a telephone interview, she said: "We have done a lot of experiments on these substances in the laboratory, which looks very promising." But she said it is not clear whether scientists can determine the DNA of dinosaurs from these substances.
China experts put forward
Three questions:
Internal DNA is difficult to determine.
Wang Wenli, a paleontologist in beijing museum of natural history, told reporters that dinosaur fossils found in the late Cretaceous are generally hardened animals. He believes that the muscles and skin of animals as old as dinosaurs can only be preserved after being mummified under certain conditions. The muscle tissue of mammoths was found in the arctic permafrost of the former Soviet Union. Wang Wenli said that even if connective tissue and cartilage preserved in dinosaur fossils can be found, these soft tissues may remain intact after hardening in the long evolutionary process, but the internal DNA is difficult to determine.
Dinosaur DNA may be mitochondrial DNA.
Dr. Deng Yajun, an expert in DNA information extraction from Beijing Institute of Genomics, Chinese Academy of Sciences, told reporters that the details of dinosaur DNA claimed by the United States are still unknown. But according to common sense, if DNA information is extracted, its DNA fragment is likely to be mitochondrial DNA, that is, cytoplasmic DNA. She said that biological DNA can be divided into cytoplasmic DNA and nuclear DNA, in which nuclear DNA is the main carrier of biological genetic information, while cytoplasmic DNA is only responsible for expressing some genetic functions.
DNA may not be able to send live dinosaurs.
Can these fragments bring us living dinosaurs? Deng Yajun said that if humans really want to clone dinosaurs, they must first ensure complete dinosaur genetic information, and it is very difficult to do this. How to obtain as much information of dinosaur nuclear DNA as possible through a series of scientific means such as PCR amplification without external pollution, and how to repair the missing part of DNA information. If there are any mistakes in this process, then copying dinosaurs is empty talk, and it will even lead to copying unimaginable monsters. When can humans breed dinosaurs? Deng Yajun's answer is: "It will take thousands of years."
Did the resurrected dinosaurs interfere with nature?
On the one hand, scientists cheered for finding clues to copy dinosaurs. On the other hand, they were asked if they agreed with scientists copying dinosaurs. Professor Liu Bing, an expert in the history of natural science in Tsinghua University, thinks that if copying dinosaurs is a partially controllable laboratory behavior, it is understandable as an academic research. But if we expect to artificially change the natural process by copying dinosaurs, then this behavior must stop. He said, is it a real dinosaur or a monster? How will the cloned dinosaurs react in the present natural environment? None of these questions can be answered. He said that in fact, in the original Jurassic Park, the author has expressed this deep concern about human intervention in natural processes through the description of catastrophic scenes.
News playback:
China claims to have obtained dinosaur DNA for the first time.
1March 995 14 Peking University College of Life Sciences announced that they had successfully obtained a dinosaur gene fragment from a special dinosaur egg. This is the first time that humans have obtained dinosaur genetic material from dinosaur eggs. In dinosaur eggs, there are still active substances of dinosaurs that died out 65 million years ago.
This egg fossil was accidentally collected by a fossil collector in 1993. Archaeologists believe that DNA molecules are preserved in this egg fossil. Under the leadership of Professor Chen from Peking University College of Life Sciences, the existence of DNA in this dinosaur egg was further confirmed by isotope labeling and PCR amplification technology, and a series of special DNA fragments were successfully amplified. Several gene fragments were obtained by DNA sequencing and computer comparison of data from the United States and Europe.
Since then, experts have further demonstrated that this conclusion is too hasty. At present, the general view in academic circles is that this experiment of Peking University scholars was polluted by external sources during the experiment. The experiment of extracting organic matter from dinosaur eggs failed.
Recently, the resurrection of extinct dinosaurs has become the focus of discussion. Scientists from Canada say that the resurrection plan can be realized by recombining ancient animal genes and artificially synthesizing cells.
"It sounds incredible." Belinda Zhang, a China evolutionary molecular biologist at the University of Toronto, led the study. But it has a solid scientific foundation. In fact, in a paper written by Nobel Prize-winning quantum chemists Linus Pauling and Emile Zuckerkand in 1963, they speculated that the sequence of ancient protein should be inferred by comparing the sequences of descendants of ancient protein. Twenty-five years later, this method was applied, and the study of ancient protein became a reality. Now scientists hope to reconstruct rhodopsin in retina by synthesizing mammalian cells artificially, so as to realize the resurrection plan.
Scientists began to study the rhodopsin gene in dinosaur retina, which is the pigment protein of all vertebrates. Because all terrestrial vertebrates have rhodopsin, dinosaurs also have rhodopsin. At present, scientists have used the gene sequence codes of visual proteins (retinal violets) of more than 30 species, including crocodiles, chickens and lampreys, to reassemble the retinal violets of ancestors of ancient reptiles, including dinosaurs, 240 million years ago.
Assuming that rhodopsin in the retina is resurrected, it is not far from the real resurrection of dinosaurs. But at the same time, the feasibility of recombining ancient animal genes according to existing animal genes has also been challenged by some scientists. Scientists who hold different opinions think that there are still some differences between the recombinant complete gene and the actual gene, such as gene mutation in the process of evolution, but it is difficult to rule out these problems in the process of recombination.
Researchers at North Carolina State University announced on March 24th that they had successfully extracted soft tissues from the fossils of three dinosaurs, including Tyrannosaurus Rex. This announcement has caused great controversy in paleontology. Traditionally, it is considered impossible to preserve the active substances of dinosaurs in fossils. With the increasingly fierce debate, the reporter interviewed Mary Schweitzer, the main person in charge of this research. Professor Schwaetzer made it clear that it was impossible to resurrect dinosaurs.
Public concern: If we can get the genetic information of cells from the soft tissues of dinosaurs, then we will be able to clone dinosaurs. For this view, Schwaetzer affirmed the impossibility, because even if the DNA information of dinosaurs was obtained, there were still many obstacles to "resurrecting dinosaurs".
Schwaetzer told reporters that although these things look like blood vessels and cells, they have not been identified as dinosaur remains by chemical analysis. "Maybe they are just remnants of minerals that we didn't realize before. This requires further study. " Questions about academic circles: If it is really the soft tissue of dinosaurs, why can it be preserved for so long? Professor Schwaetzer answered frankly that she had not figured out the problem.
Schwaetzer revealed that their research team is trying to analyze the substances they extracted to determine whether there are dinosaur molecules in these substances. "We want to confirm the composition of these substances and their chemical changes when they are transformed from biology to their present state."