The word clone is transliterated from clone. Before the transliteration appeared, there was a free translation name - asexual reproduction system, which refers to a group of cells obtained by mitosis of a single cell or the same ancestor. organic group. We can obtain a cell clone through cell culture.
A brief history of cloning technology (small information)
In 1938, the first modern embryologist, Dr. Hans Spielmann of Germany, suggested using mature cell nuclei to implant eggs methods for mammalian cloning.
In 1952, using Spielman's idea, the world's first cloned frog appeared.
In 1962, John Gurdon announced that he had cloned a tadpole from a mature cell, sparking the first debate about cloning.
In 1984, Steen Willardson cloned a sheep from embryonic cells. This is the first confirmed case of cloned mammal.
In October 1995, Dr. Vacanti, an anesthesiologist from Massachusetts, USA, used modified tissue engineering to grow human ears on the backs of mice, allowing humans to grow ears in the laboratory that can be transplanted to humans. Skin and cartilage.
In July 1996, the Roslin Institute in Scotland, UK, successfully cloned the little sheep "Dolly" from sheep mammary gland cells.
In October 1997, British experts developed a headless frog embryo, allowing their technology to produce human organs for medical transplantation.
In July 1999, Japanese scientists cloned multiple cows and put their meat on the market.
In April 2000, the American Advanced Cell Engineering Company cloned six calves that were younger than their actual age.
In 2000, American scientists successfully cloned a monkey "Tetra" using asexual reproduction technology, which means that there are no technical barriers to human cloning itself.
On November 25, 2001, a biotechnology company in Massachusetts successfully cloned a human embryo, taking an important step in cloning technology. However, the company said its purpose is not to clone humans, but to obtain stem cells that can be used to treat various diseases such as Parkinson's disease and juvenile diabetes.
What is cloning?
The word clone is transliterated from clone. Before the transliteration appeared, there was a free translation name - asexual reproduction system, which refers to a group of cells obtained by mitosis of a single cell or the same ancestor. organic group. We can obtain a cell clone through cell culture. In microbial experiments, by pouring the flat plate, we can get colonies one by one. These colonies are actually clones of bacteria. It can be seen that clone is originally a noun, referring to a group of cells or a group of individuals. With the development of molecular biology, operations such as nuclear transplantation and genetic engineering have emerged. The nuclear transfer operation can obtain reconstructed cells, and the reconstructed cells can be propagated into a clone; the genetic engineering operation can splice a selected gene into the replicon of the plasmid, and as the replicon replicates, the clone of the DNA molecule can also be obtained. Tie. Therefore, some people call this type of operation cloning, that is, converting the word clone from a noun to a verb, and calling nuclear transplantation nuclear cloning, and the clones of DNA molecules obtained through genetic engineering are called molecular cloning. clone). Cloning here is an operation to achieve asexual reproduction, which is a microscopic operation or molecular biology operation, rather than asexual reproduction (or asexual reproduction operation) in the general sense. This may be why the term cloning exists and is not replaced by asexual reproduction.
Clone Sheep
Dolly the sheep, also known as cloned sheep, is actually a sheep produced using nuclear cloning technology. Some people say that only Dolly the sheep is the real cloned sheep. Other reports, such as cloned pigs, cloned cows, etc., are not true because they are developed from embryonic cells, and embryonic cells are produced through sexual reproduction. clone on. This is a misunderstanding caused by an inaccurate grasp of the time of the sexual process. The sexual process ends when the fertilized egg, that is, the zygote, is formed. Once the zygote division begins, it has nothing to do with the sexual process. If the divided embryonic cells are produced by sexual reproduction, then somatic cells are also produced by sexual reproduction.
But in fact they are all gradually produced from the zygote through mitosis. That is to say, sexual reproduction is actually achieved through one sexual process and many asexual processes, and finally produces a living offspring. Taking a cell from an embryo to develop it into an individual is obviously asexual reproduction. Therefore, in this sense, Du Lishu is the founder of cloning technology (cell cloning technology). His experiment of separating cells at the two blastomere stages and allowing them to develop into two sea urchins was the earliest cloning experiment. Human identical twins are produced by cloning of natural cells. As for cloned pigs and cloned cows, if they are bred through nuclear transfer, regardless of whether the nuclear donor cells are from early embryonic cells or differentiated cells, they are all cloning technologies in the true sense, and they are much higher than Du Lishu's level. Many cloning technologies.
Getting closer to "gene drugs"
In order to achieve a certain purpose, people integrate the cloned exogenous target gene (usually human DNA) into the chromosomes of animal fertilized eggs. Such animals containing foreign genes are called transgenic animals so that they can be expressed in animals and stably passed on to future generations. Scientists engaged in this research said that a transgenic animal is a natural genetic drug manufacturing factory, which can not only It greatly reduces costs, and can also expand production and obtain more genetic drugs.
Using genetically modified animals to produce genetic drugs is a brand-new production model that is incomparable compared with traditional pharmaceutical technology. Advantages. Taking the United States as an example, the annual requirement of coagulation factor VIII is about 120 grams. In the past, 1.2 million liters of plasma were required to extract this 120 grams of coagulation factor VIII, which required 600 blood donors based on each person donating 200 ml of blood. Plasma can be used to meet the needs. If genetically modified cows are used for production, the annual milk output of one cow is 10,000 kilograms. If each kilogram of milk can produce 10 mg of coagulation factor VIII, then only 1.2 such cows can meet the needs. Taking albumin as an example again, the annual demand in the United States is 100,000 grams. In the past, it needed to be extracted from 2 million liters of plasma. However, if genetically modified cattle are used to produce 2 grams of protein per kilogram of milk, only 5,000 cows are needed. Cows can be solved. In addition, infectious diseases such as hepatitis and AIDS that may occur by extracting serum proteins from human blood can also be avoided. Biotechnology is the most active technology today. In 1971, the Nobel Prize was awarded. Paul Berg successfully spliced ??two different genes together for the first time, bringing biotechnology to a new stage of gene recombination and transplantation.
Since then, gene recombination technology has achieved fruitful results one after another. Artificial insulin was synthesized in 1978, the growth hormone gene was expressed in E. coli in 1979, and artificial interferon was successfully developed in 1982. Gene pharmaceuticals have since embarked on the road to industrialization. However, the current genetic medicines are based on genetic recombination. It is produced by cultivating E. coli and animal cells, but it is impossible for lower organisms such as E. coli to produce drugs with complex structures, and the cost of cultivating animal cells is too high. Therefore, genetic recombination and transplantation technology are used to cultivate transgenic animals. The production of drugs came into being. British scientists were the first to use genetically modified animals to extract drugs. At the end of 1997, the British company PPL Therapeutics took the lead in using the "nuclear transformation" method used to clone "Dolly" to cultivate 200 human-carrying animals. Genetically engineered sheep and successfully extracted α-1 antitrypsin from the milk. This is the first time that scientists have extracted pharmaceutical ingredients that can be used to treat human diseases from the milk of genetically engineered sheep, laying the foundation for the establishment of an "animal pharmaceutical factory." " The foundation was laid. Subsequently, Finnish scientists implanted the human erythroblastin gene into the fertilized eggs of dairy cows and created a cow that can produce erythroblastin. Theoretically, this kind of cow can survive for one year It can extract 60-80 kilograms of erythrotropin, which is more than what is currently used in the world.
If you are a football fan, you definitely hope to have another Ronaldo in the world; if you are a music lover, of course you are willing to have another Beethoven; and there is also an Edison and Einstein that many people want. Dreamy. An ancient Greek philosopher once said, "There cannot be two identical leaves in the world." In other words, the above dreams can only be fantasies and have no possibility of realization. However, the situation has changed now. There is an emerging biotechnology "cloning" that may be able to do this.
So what is cloning? What's so wonderful about it? Today, let's get closer together - "Wonderful Cloning".
Which animals and plants around us have the innate ability to clone? Animals and plants with the ability to clone include: potatoes, earthworms, mulberry trees, loofah vines, spider plants, jellyfish, sea cucumbers, and cacti. After a jellyfish is injured, the wound will heal automatically. Octopuses can regenerate their tentacles. If a lobster's claws fall off, they will grow back again. There are also Begonias and Lucky Bamboo, which come alive after cuttings. gecko. When it encounters danger, it cuts off its tail and then grows it back.
Can you find out the similarities between these animals and plants that are born with the ability to clone? In your own words, what is cloning? Offspring that are not produced by the combination of germ cells.
Cloning technology can benefit mankind: it can expand the reproduction of animals that cannot reproduce, such as mules, and it can also save endangered animals.
If you also mastered cloning technology, what would you want to clone? Why clone it? Requirements: 1. The idea must be wonderful; 2. The idea must be beneficial to mankind; 3. The expression must be organized and the tone and intonation are appropriate.
If I were asked to clone, I would clone countless pairs of clear eyes. Many people take having good eyes for granted, but I don’t. When you see those eyes without light and hear the call of a soul longing for light, isn't your heart shaken? God is unfair to them, so let science create light for them, and let society let them experience true love. I firmly believe that "technology is people-oriented" is not empty talk. So I want to clone eyes and let more people see again.
I want to clone dinosaurs. Because I like dinosaurs and want to recreate the grand scene of the dinosaur era. And it has the conditions to clone dinosaurs, because Antarctica in the dinosaur era may have been in a temperate zone. When the dinosaurs died and their bodies were hidden in Antarctica, the Antarctic was probably already in the ice and snow at this time. Since the cold can prevent the body from decaying, Dinosaur DNA can be extracted to clone dinosaurs, which can also broaden the horizons of future generations.
I do not advocate cloning some prehistoric creatures, such as dinosaurs and ferocious ants, as he did. Because the survival and extinction of any living thing is beyond human control, human beings should strictly abide by the "laws of nature" and let the development of living things take its course. If we go back to the past, we may destroy the ecological balance.
I want to clone water. There is currently a serious shortage of fresh water resources in the world, which can no longer sustain human survival, and humans are still wasting water without limit, so I want to clone water.
I want to clone food and save the starving people in Africa so that they can live a life of food and clothing.
We all know that tropical rainforests are the lungs of the earth. The Amazon Plain is the largest tropical rainforest in the world, accounting for 50% of the total area of ??tropical rainforests on the planet, covering 6.5 million square kilometers. It is rich in natural resources and species and is known as a "biologist's paradise". However, Amazon is not loved by people because of its wealth. Since the 1970s, one-third of its face has disappeared before our eyes due to indiscriminate deforestation, which will mean that the oxygen that sustains human survival will be reduced by one-fifth. So, I want to clone the Amazon rainforest and place it on the Sahara Desert to clean up the environment.
I object to what the three students just said. Their ideas are very good, expressing their concern for the country and the people, and expressing their good wishes. But water, tropical rain forests, and food do not have cells, so how can they be cloned? (Audience laughs) (Someone interrupts in a low voice): Water is okay, there are water molecules.
If I had cloning technology, I would clone Sun Wukong, because he is omnipotent and can realize many of our ideals of changing society. (Everyone laughs)
Teacher: Thank you to these students for bringing you bold and novel "cloning ideals". Regardless of whether they conform to scientific principles or not, they all express your good wishes and hope. Technology can bring about social progress and make human life happier! The discussion centered on the topic "Cloning technology benefits mankind?!" )
Teacher: Debate requirements: (1) The language is clear and fluent, and the voice is loud; (2) The views are clear and the arguments are sufficient; (3) When refuting the other party’s views, you must be both "reasonable" and reasonable "present".
(Debate with "cloning technology can benefit mankind" as the affirmative and "cloning technology cannot benefit mankind" as the negative)
Pro: I think "cloning technology can benefit mankind", Doesn’t the fourth chapter of the text introduce the role of cloning on human beings in great detail? If animals without the ability to reproduce can be expanded to reproduce, according to relevant reports, how can mules, hybrid animals born from male donkeys and female horses, reproduce these excellent breeds? Only clone can be used. It can also save endangered animals such as pandas with low reproductive capacity.
Opposition: I think cloning is not beneficial to mankind. Don't believe it, please listen to me slowly. (Pause, because he was too excited, he repeated it again, everyone laughed) First of all, as the positive debater said, cloning can indeed save endangered animals, but have you ever thought that such cloning will destroy the normal development of animal populations and cause animals to Weakness, even if it can be saved for a while, can it be saved for the whole life? I don't think so. Some people say that cloning can regenerate animals and plants. Have you ever thought that as long as humans do not deliberately destroy it, this ecological balance has been maintained for tens of millions of years. Whether your unlimited cloning will destroy its food chain is another question. What about the destruction of ecological balance?
True: I heard that nearly a hundred species of plants disappear every day in the Amazon rainforest, so cloning can save some of the plants, not all, but some of them. Although the current cloning technology is not very developed, I believe that the level of cloning will be better in the future. Cloning will have its place at this time. We can't wait until the earth is completely desolate before we study cloning, right?
Opponent (sneering): The other debater is really full of hope for the future! But this also proves that this is just your beautiful imagination, placing your hope on the improvement of cloning technology. In fact, after 247 failures, the cloned little sheep "Dolly" was obtained. How many animals need to be harmed in this process? Doesn’t this run counter to our original intention of cloning?
Zhengfang: Failure is the mother of success! (Laughter) The current cloning technology may be underdeveloped, but in the future I believe that human cloning will get better and better, and the cloned animals and plants will get better and better, and things like 247 failures will no longer happen. It will ultimately benefit humanity. Moreover, cloning plays an important role in studying some diseases and studying human lifespan. When one day there is a problem with one of our own organs, we can take out the organ from the previously cloned embryo and culture it, and then replace the diseased organ. We no longer have to be afraid of disease. So cloning is still beneficial to humans.
Opponent: Do you still think the world’s population is not large? If organs are replaced whenever there is a serious disease, wouldn’t everyone be able to live forever? If this is the case, wouldn’t the growth rate of the earth’s population reach an extreme, and wouldn’t there be a crisis on the earth?
Zhengfang: Maybe then people can live on other planets! (Audience laughs)
Opponent: I want to talk about the dangers of human cloning. (Students from the opposing side applaud) For example, if the cloned donor cells mutate, or the cultured genes for culturing embryos make a little joke with scientists and clone a waste product, can we treat them like dogs and cats? There is a shortage of donors for organ transplantation. Can you prepare for a rainy day and clone an organ warehouse for yourself to provide for future unexpected needs? If so, can people calmly take out a kidney and dig out an eye from a clone with the same facial features and rich expressions as us? Humans have long expected to use robots to relieve themselves from heavy or dangerous labor, but even the most dexterous robots are clumsy and unsatisfactory. Is it possible to clone a substitute for "me" and give him dexterous limbs and the will to obey absolutely? If so, will one day the awakened clones shout to us: "Princes, generals, ministers, would you rather be born?" (Students on the opposite side applauded warmly and cheered loudly)
Clone clones according to the same pattern A new life for them, are they sons or younger brothers? If we were faced with a group of clones with the same appearance, body shape, and demeanor, how would we confirm their identities? If they commit a crime, what means do we have to find the real culprits? Besides, the earth inhabited by humans has already been burdened by the population explosion. What reason do we have to use another method to produce ourselves? (Applause breaks out again)
Zhengfang (excitedly): Things always have two sides. You can’t judge very decisively whether it is good or bad. I think a technology must have a reason for its existence. You cannot deny that it benefits mankind, and you cannot beat it to death with a stick.
Whether cloning technology can benefit mankind depends on what it is cloning and in what field. Of course it has disadvantages because everything has its two sides and cannot be purely good or bad, so we cannot say cloning Technology is absolutely useless.
Teacher (while pausing, the students are still very excited): The students expressed their opinions and put forward many opinions on this. They may not be profound enough, but they are simple and true. Frankly speaking, my knowledge in this area may not be higher than yours, but your speeches inspired me. Cloning technology has made breakthrough progress, and the world has been shocked by it. Does it do more good than harm to us humans, or does it do more harm than good? It is too early to draw a conclusion now. This text quotes the Nobel Prize winner, the famous Molecular biologist J. D. Watson's words conclude: "Many biologists, especially those engaged in the study of asexual reproduction, will seriously consider its implications and launch scientific discussions to educate the people of the world." This is exactly what it means. What we are looking forward to, we hope that "cloning technology will benefit mankind".