In 1952, using Spearman's idea, the world's first cloned frog appeared.
In 1962, John? Gurdon announced that he had cloned a tadpole from a single mature cell, sparking the first round of debate on cloning.
In 1984, Steen? Willardson cloned a sheep from embryonic cells. This was the first confirmed cloning of a mammal.
In October 1995, Dr. Vikenty, a Massachusetts anesthesiologist, used modified tissue engineering to cause human ears to grow on the backs of rats, thus allowing humans to grow skin and cartilage in the laboratory that could be transplanted to humans.
In July 1996, the Rosslyn Institute in Scotland, England, succeeded in cloning Dolly the sheep from sheep's mammary gland cells.
In October 1997, British experts developed a headless frog embryo, making it possible to create human organs for medical transplants.
In July 1999, Japanese scientists cloned several cows and marketed their meat.
In April 2000, the U.S. company Advanced Cellular Engineering cloned six calves younger than their actual age.
In 2000, U.S. scientists successfully cloned a monkey, Tetra, using asexual reproduction techniques, which meant that there were no technical barriers to human cloning itself.
November 25, 2001, the United States of America Massachusetts biotechnology
Respondent: Edogawa Mourning - probationary period first level 3-20 19:14
A bacterium can be split in two after 20 minutes or so; a grapevine branch cut into ten segments may become ten grapes; the cactus is cut into a number of pieces, each piece of the ground on the roots; a strawberry plant depends on it to "crawl" along the ground. Along the ground "crawling away" stolon, within a year can grow hundreds of strawberry seedlings ...... All of these are living creatures rely on their own into two or a small part of their own expansion to reproduce offspring, this is asexual reproduction, asexual reproduction of the English name called The English name of asexual reproduction is called "Clone", which is translated as "clone". In fact, the English word "Clone" originated from the Greek word "Klone", which originally meant to use the word "clone". In fact, the English word "clone" originated from the Greek word "Klone", which originally meant to propagate by "shoots" or "cuttings". Today, the meaning of "clone" is not only "asexual reproduction", but also "clone", which means a group of individuals from a single ancestor who have been reproduced asexually. This group of asexually reproduced offspring from a single ancestor is also called an "asexual line", or asexual line for short.
You're writing an essay, and I'm giving it to you
Time flies like an arrow, and years go by like a shuttle, and in the blink of an eye more than a decade has passed, and I've become a senior expert in the field of cloning. Now, cloning technology has been accepted by people. Cloning has restored the original color of the forest, and it is the animals that have found their green homes, so that people can lead a happy life.
New subjects have been formed in my mind, from fuzzy to clear. Cloning Human Organs - Eyes. The Story of My Life - The Autobiography of Helen Keller is my favorite book. From the time I saw that book, I was impressed by the spirit of the main character, Helen Keller, who was persistent and never bowed down in the face of difficulties. I felt sorry for Helen Keller for losing her sight, but secretly glad that fate was not so cruel to me. However, because I do not pay attention to eye hygiene, eventually got myopia, my eyes became a blurred world, no way, I had to set up a pair of glasses at a young age. "If I can get so much happiness just by touch, how many beautiful things will be shown by sight!" This is a line written in Helen Keller's "If You Give Me Three Days' Light", which may more y reflect the status of eyes in people's lives. Please protect your eyes, how precious it is to have a pair of bright eyes.
When I thought of this, I finally made up my mind, I want to clone eyes. I will succeed, because I know that there are many people in the world who suffer from eye diseases, and they need a pair of healthy eyes; there are many people in the world who live in darkness, and they need a pair of bright eyes even more! I want to clone a pair of eyes, so that those patients who are in pain, in time to replace the healthy eyes, get rid of the entanglement of the disease, to be a healthy and happy people.
This is probably my future, a cloning expert. I want everyone to have a pair of bright eyes, but I hope more than anything that people can protect the pair of bright eyes that belong to us.
Respondent: Meng Dish Dance - Trial Level 3-20 19:16
A bacteria can be divided into two after about 20 minutes; a grape branch cut into ten sections may become ten grapes; cactus cut into several pieces, each piece of the ground on the roots; a strawberry plant relying on the stolon along the ground, can grow several plants in a year; a strawberry plant along the ground "crawling away", can grow a lot of people. A strawberry plant can grow hundreds of strawberry seedlings within a year....... All of these are biological organisms rely on their own into two or a small part of their own expansion to reproduce offspring, which is asexual reproduction, asexual reproduction of the English name is called "Clone", which translates to The English name for asexual reproduction is "Clone", which translates to "clone". In fact, the English word "Clone" originates from the Greek word "Klone", which originally means "shoot" or "plug". In fact, the English word "clone" originated from the Greek word "Klone", which originally meant to propagate by "shoots" or "cuttings". Nowadays, the meaning of "clone" is not only "asexual reproduction", but also "clone", which means a group of individuals from a single ancestor, reproduced asexually. This group of asexually reproduced offspring from a single ancestor is also called an "asexual line", or asexual line for short.
Respondent: wuhao8637 - Lifter IV 3-20 19:17
Cloning Technology
1938: German scientists put forward the idea of cloning for the first time.
1952: Scientists begin cloning experiments with frogs.
1970: A breakthrough was made in frog cloning, as frog eggs developed into tadpoles, but died after
starting to eat.
1981: Scientists clone rats, allegedly producing normal rats from rat embryonic cells.
1984: The first embryonic cloned sheep is born.
February 24, 1997: The Roslin Institute in England announces the successful breeding of cloned sheep. Science
A cloned sheep is bred at home from mammary cells taken from a 6-year-old adult sheep.
February 23, 1998: PPL Medical of the United Kingdom announced that it had cloned a calf, "
Mr. Jefferson".
July 5, 1998: Japanese scientists announced the birth of two calves they had cloned
using adult animal body cells.
July 22, 1998: Using a new cloning technique, scientists have successfully bred more than 50 cloned rats of the third generation*** from adult rat body cells
cells, which is the first time that humans have ever cloned a cloned animal from a cloned animal
.
May 31, 1999: Scientists at the University of Hawaii, U.S., clone the first male rat using adult somatic cells
.
June 17, 1999: A research team led by Chinese-American scientist Xiangzhong Yang clones a calf using cells removed from the ear of
a 13-year-old cow.
January 3, 2000: Xiangzhong Yang, a famous Chinese American, successfully cloned six calves using cells from the ear skin of a bull
after a long period of in vitro culture.
January 2000: U.S. scientists announced the successful cloning of a rhesus monkey, which was named "
Tetra".
March 14, 2000: The British company PPL, which was involved in the cloning of Dolly the sheep, announced that
they had succeeded in producing five cloned pigs.
Status of research on cloning technology
I. Early research on cloning
The word clone is the phonetic translation of the English word clone, and as a noun, c1one is usually translated as asexual reproduction line. The genetic makeup of all members of the same clone is identical, with exceptions only when mutations occur. Natural clones of plants, animals, and microorganisms have long existed in nature, e.g., identical twins are actually clones. However, since natural mammalian clones are so infrequent, have so few members (typically two), and lack purpose that they can rarely be used for human benefit, artificial methods of producing higher animal clones have been explored. In this way, the word clone began to be used as a verb to refer to the action of artificially breeding cloned animals.
At present, the two main methods of producing mammalian clones are embryo splitting and cell nuclear transfer. The cloned sheep "Dolly", as well as a variety of cloned animals bred by scientists in various countries since then, have adopted the cell nuclear transplantation technology. The so-called cell nuclear transplantation refers to the process of transplanting the nuclei of embryos or adult animals of different developmental periods into denucleated oocytes through microsurgery and cell fusion, so as to reorganize the embryo and make it mature. Unlike embryo splitting, nucleus transplantation, especially serial nucleus transplantation, can produce an unlimited number of genetically identical individuals. Because cell nuclear transplantation is an effective method of producing cloned animals, it is often referred to as animal cloning technology.
The idea of animal cloning by nucleus transplantation was first proposed in 1938 by Hans Spemann, who called it a "strange experiment" in which the nucleus of a cell was removed from an embryo at a late stage of development (mature or immature embryo is acceptable) and transplanted into an egg. This idea is now the basic route to cloning animals.
From 1952, scientists first used frogs to carry out nuclear cell transplantation cloning experiments, and successively obtained tadpoles and adult frogs. 1963, China's scientific research group under the leadership of Prof. Tong Di Zhou, first to goldfish and other materials, research on fish embryo nuclear cell transplantation technology, and achieved success.
The first results of mammalian embryonic cell nuclear transplantation research in 1981 - Karl Ilmenzer and Peter Hoppe with mouse embryonic cells to breed a normal development of mice. 1984, Sten Veladsen with immature embryonic cells taken from sheep cloned a live birth of sheep, and others later replicated the experimental methods he employed using a variety of animals, including cows, pigs, goats, rabbits, and rhesus monkeys. in 1989, Villadsen obtained cloned cows with two consecutive nucleus removals. in 1994, Neil Feldstetter cloned cows from late-stage embryos that had developed to have at least 120 cells. By 1995, nuclear transfer of embryonic cells had been successful in all major mammals, including frozen and in vitro-produced embryos; experiments with nuclear transfer of embryonic stem cells or adult stem cells had also been attempted. However, until 1995, nuclear transplantation of differentiated cells from adult animals had not been successful.
The significance of the cloned sheep "Dolly" and the repercussions
The above facts show that, in February 1997, Dr. Wilmut's scientific research group at the Roslin Institute in the United Kingdom announced that somatic cell cloning of the sheep "Dolly" cultivation success, the embryonic cell nuclear transfer technology has already been successful. The technology of embryonic cell nuclear transfer had already been greatly developed. In fact, the cloning of "Dolly" followed the entire process of embryonic cell nuclear transplantation, but this does not diminish the great significance of "Dolly", because it is the world's first animal born through somatic cell nuclear transplantation, which is a great breakthrough in the field of cloning technology. This is a huge breakthrough in cloning technology. This great progress means that: theoretically, it has been proved that, like plant cells, the nucleus of differentiated animal cells also has totipotency, and there is no irreversible change of the genetic material in the nucleus during the process of differentiation; practically, it has been proved that it is feasible to utilize somatic cells for animal cloning, and that there will be countless identical cells that can be used as the donor for nuclear transplantation, and a series of complex genetic manipulations can be carried out on the donor cells before fusing with the oocytes. These donor cells can be subjected to a series of complex genetic manipulations before fusion with the egg cell, thus providing an effective method for large-scale replication of superior animal breeds and production of transgenic animals.
Theoretically, using the same method, a human being could be reproduced as a "clone," which means that the idea of the authoritarian maniacs of science fiction cloning themselves is entirely possible. Therefore, the birth of "Dolly" in the world's scientific community, political and even religious circles have caused a strong reaction, and triggered a discussion of the moral issues derived from human cloning. Relevant people in governments and civil society have responded that human cloning is contrary to ethics and morality. Nevertheless, the great theoretical significance and practical value of cloning technology has prompted scientists to speed up the pace of research, so that the research and development of animal cloning technology has entered a climax.
Three important results of cloning research in the past three years
The birth of the cloned sheep "Dolly" set off a wave of cloning research all over the world, followed by a succession of reports about cloning animals. In March 1997, one month after the birth of "Dolly", scientists from the United States, Taiwan and Australia published news of their successful cloning of monkeys, pigs and cows respectively. However, they all used embryonic cells for cloning, the significance of which cannot be compared with that of "Dolly". In July of the same year, the Roslin Institute and PPL announced the cloning of the world's first transgenic sheep with human genes, Polly, from genetically modified fetal fibroblasts. This achievement demonstrates the great value of cloning technology in breeding transgenic animals.
In July 1998, Wakayama et al. of the University of Hawaii reported that 27 viable mice were cloned from mouse ovary cells, of which 7 were cloned again from cloned mice, which is the second batch of mammalian somatic cell nuclear transplantation progeny after "Polly". In addition, Wakayama et al. used a new, relatively simple and highly successful cloning technique, different from that of Dolly, which was named the "Honolulu Technique" after the location of the university.
Since then, scientists in the U.S., France, the Netherlands, and South Korea have reported successes in cloning cows from somatic cells; the enthusiasm of Japanese scientists has been particularly impressive, with the Tokyo University of Agriculture and Technology, Kinki University, the Livestock Improvement Organization, and local (Ishikawa, Oita, and Kagoshima prefectures, etc.) livestock testing facilities, as well as private companies (such as Yukihin Dairy, the largest milk commodity company in Japan) working from July 1998 to April 1999 on cloning cows from Somatic Cell Cloning. The results of cloning cows from ear and rump muscles, ovarian mound cells, and mammary gland cells extracted from colostrum have been reported by dairy companies such as Snow Seal Dairy, the largest dairy company in Japan. By the end of 1999, somatic cell cloning offspring of six types of cells - fetal fibroblasts, mammary gland cells, ovarian mound cells, oviduct/uterine epithelial cells, muscle cells, and ear skin cells - had been successfully born worldwide.
In June 2000, China's Northwest A&F University of Science and Technology using adult goat body cells cloned two "cloned goats", but one due to respiratory dysplasia and early death. According to reports, the cloning technology used for the research group's own research, and the cloning of "Dolly" technology is completely different, which shows that Chinese scientists have also mastered the cutting-edge technology of somatic cell cloning.
In the different species of cell nuclear transplantation experiments have also achieved some encouraging results, in January 1998, the United States, the University of Wisconsin-Madison scientists to the cow's egg as a receptor, the success of the cloning of pigs, cows, goats, mice and rhesus monkeys five kinds of mammal embryos, the results of this study show that a species of unfertilized eggs can be taken from a variety of animals with the combination of mature cell nuclei. Although these embryos were aborted, it made a useful attempt to the possibility of heterologous cloning. 1999, American scientists cloned the embryos of the rare animal Pan sheep with cow eggs; Chinese scientists also cloned the early embryos of giant pandas with rabbit eggs, and these results show that cloning technology has the potential to become a new way to protect and save endangered animals.
Application Prospects of Cloning Technology
Cloning technology has demonstrated broad application prospects, summarized in the following four aspects: (1) breeding of fine livestock breeds and production of experimental animals; (2) production of genetically modified animals; (3) the production of human embryonic stem cells used in cellular and tissue replacement therapy; (4) copying of endangered species of animals, preservation and dissemination of animal species resources. The following is a brief description of the production of transgenic animals and embryonic stem cells.
Transgenic animal research is one of the most attractive and promising topics in the field of animal bioengineering, and transgenic animals can be used as donors for medical organ transplants, as bioreactors, as well as for the genetic improvement of livestock and the creation of experimental models of diseases. However, at present, the practical application of transgenic animals is not much, in addition to a single gene modification of transgenic mice medical model has been applied earlier, transgenic animal mammary gland bioreactor production of drug proteins in the research of a longer period of time, has been carried out for more than 10 years, but at present in the world only 2 cases of drugs into the phase 3 clinical trials, 5 to 6 drugs into the phase 2 clinical trials; and its agronomic traits have been improved, can be funded No transgenic livestock lines with improved agronomic traits that can be used in livestock production have been born so far. The low production efficiency of transgenic animals, the high cost and regulatory failure caused by the difficulty of fixed-point integration, as well as the separation of genetic traits in the sexually reproduced offspring of transgenic animals and the difficulty of maintaining the excellent traits of the originator are the main reasons restricting the process of the practical application of transgenic animals today.
The success of somatic cell cloning has set off a new revolution in the production of transgenic animals, and the technique of animal somatic cell cloning has provided a technical possibility for the rapid amplification of the germplasm innovation effect produced by transgenic animals. The use of simple somatic cell transfection technology to implement the transfer of target genes can avoid the difficulties and inefficiencies of livestock germ cell sources. At the same time, the use of transgenic somatic cell lines allows pre-testing for transgene integration and pre-selection for sex under laboratory conditions. Before nuclear transfer, the fusion gene of the target exogenous gene and marker genes (e.g., LagZ gene and neomycin resistance gene) is introduced into cultured somatic cells, and then the transgene-positive cells and their clones are screened by the performance of the marker genes, and then the nucleus of this positive cell is transplanted into denucleated oocytes, and the final animals produced should theoretically be 100% positive transgenic animals. Using this method, Schnieke et al. (Bio Report, 1997) have successfully obtained 6 transgenic sheep, of which 3 with the human coagulation factor IX gene and marker gene (neomycin resistance gene), and 3 with the marker gene, with the integration rate of the target exogenous gene as high as 50%.Cibelli (Science, 1997) has similarly obtained 3 transgenic cows by using nuclear transplantation, confirming the method. Cibelli (Science, 1997) also utilized the nuclear transfer method to obtain three transgenic cattle, confirming the effectiveness of the method. From this, we can see that one of the most important application directions of animal cloning technology today is the research and development of high value-added transgenic cloned animals.
Embryonic stem cells (ES) are totipotent stem cells with the potential to form all adult cell types. Scientists have been trying to induce targeted differentiation of various stem cells into specific tissue types to replace those damaged body tissues, such as implanting insulin-producing cells into diabetic patients. Scientists have been able to transform porcine ES cells into beating heart muscle cells, human ES cells into neuronal and mesenchymal cells and mouse ES cells into endodermal cells. These results open the way for cell and tissue replacement therapies. Currently, scientists have succeeded in isolating human ES cells (Thomson et al. 1998, Science), and somatic cell cloning techniques offer the possibility of producing a patient's own ES cells. The patient's somatic cells are transplanted into enucleated oocytes to form a recombinant embryo, the recombinant embryo is cultured in vitro to a blastocyst, from which ES cells are then isolated, and the ES cells obtained are made to differentiate directionally into the specific cell types required (e.g., nerve cells, muscle cells, and blood cells) for use in alternative therapies. The ultimate goal of this nuclear transfer method is to use the cells for stem cell therapy, not to obtain a cloned individual, which scientists call a "therapeutic clone.
The use of cloning in basic research is also of great interest, as it provides tools for studying mechanisms of gametogenesis and embryogenesis, cell and tissue differentiation, regulation of gene expression, and nucleoplasmic interactions.
V. Problems of cloning technology
Although cloning technology has a wide range of application prospects, it is still a long way from industrialization. Because as an emerging field of research, cloning technology is still very immature in theory and technology, in theory, differentiated somatic cell cloning on the genetic material reprogramming (all or most of the genes in the cell nucleus shut down, the process of cellular re-establishment of totipotency) of the mechanism is still not clear; cloned animals whether they will remember the age of the donor cells, the successive progeny of the cloned animal whether the accumulation of mutant genes, and in the cloning The genetic role played by cytoplasmic mitochondria during cloning is still unresolved.
In practice, the success rate of animal cloning is still very low, Wilmut's research group in the cultivation of "Dolly" experiments, the fusion of 277 transplanted nucleus of the oocyte, only to obtain "Dolly", a live lamb, the success rate of only 0.36%, while the simultaneous conduct of the "Dolly", the success rate of only 0.36%, the success rate of only 0.36%. The success rate was only 0.36%, and the success rates of the simultaneous cloning experiments of fetal fibroblasts and embryonic cells were only 1.7% and 1.1%, respectively, and the success rate was only a few percent even when using the "Honolulu" technique, which uses less differentiated oocytes as the nucleus donor.
In addition, some of the individuals born showed physiological or immune deficiencies. Taking cloned cattle as an example, many cloned cattle bred in Japan, France and other countries died within two months after birth; by February 2000, 121 somatic cell cloned cows had been **** born throughout Japan, but only 64 survived. Observations have shown that some calves' placentas are not functioning well, and their blood oxygen levels and growth factor concentrations are lower than normal; some calves' thymus, spleen, and lymph glands have not developed properly; and there is a general tendency for cloned animal fetuses to develop more rapidly than normal, all of which may have contributed to the deaths.
Even normally developing "Dolly" has been found to show signs of premature aging. In 1998, scientists found that the telomeres of Dolly's cells were shorter than normal, meaning the cells were in a more senescent state. At that time, it was thought that this might be caused by cloning "Dolly" with adult sheep cells, so that its cells have the imprint of adult cells, but this explanation is now being challenged, the United States of America, Massachusetts doctor Robert Lanza and other cultured senescent cell cloning cattle, to get six calves, 5 to 10 months after birth found that these cloned cattle The telomeres of these cloned calves were found to be longer than those of ordinary calves of the same age, and some were even longer than those of ordinary newborn calves. It is not clear why this phenomenon occurred, or why it was so different from the case of Dolly. But the experiment suggests that in some cases the cloning process can alter the molecular clock of mature cells to "rejuvenate" them, and it remains to be seen how such changes affect the lifespan of cloned animals.
In addition to the above theoretical and technical obstacles, the ethical impact of cloning technology (especially in the application of human embryos) and the public's strong reaction to it have also limited the application of cloning technology. However, the development of cloning technology over the past few years has shown that all the major scientific and technological countries in the world are not willing to lag behind, and no one has given up the research on cloning technology. The attitude of the British Government is very representative. Less than a month after the announcement of the suspension of investment in the Dolly research team at the end of February 1997, the British Science and Technology Commission issued a special report on cloning technology, indicating that the British Government would reconsider this decision and that it was not wise to blindly prohibit research in this area. The key is to establish certain norms to utilize it for the benefit of mankind.
Cloning is the phonetic translation of clone, which is simply an artificially induced form of asexual reproduction. But cloning is different from asexual reproduction. Asexual reproduction refers to the reproduction of offspring from a single organism without the union of male and female reproductive cells, commonly known as sporulation, budding and schizogamy. Asexual reproduction is the production of new individuals from plant roots, stems, leaves, etc. by pressing, cutting, or grafting. Animals such as sheep, monkeys and cows cannot reproduce asexually without artificial manipulation. Scientists call the process of reproduction of animals and plants by artificial genetic manipulation cloning, and this biotechnology is called cloning technology.
The idea of cloning technology was first proposed by a German embryologist in 1938, and in 1952, scientists first used frogs to carry out cloning experiments, and after that, people continued to utilize a variety of animals to carry out research on cloning technology. Since the technology has made little progress, the research work once entered a low point in the early 1980s. Later, some people used mammalian embryonic cells for cloning success. On July 5, 1996, Dr. Ian Wilmut, a British scientist, cloned a live-born sheep from the body cells of an adult sheep, which brought a major breakthrough to the research of cloning technology, breaking through the technical difficulties of animal cloning that could only be carried out with embryonic cells in the past, and realizing for the first time the goal of animal cloning with body cells, and realizing animal replication of a higher significance. The goal of the cloning research is to find better ways to alter the genetic makeup of livestock and to breed herds of animals that can provide consumers with better food or any chemical substance they may need.
The basic process of cloning is to transfer the nucleus of a donor cell containing genetic material into an egg cell that has had its nucleus removed, stimulate it with a microcurrent, etc., and cause the two to fuse together, then cause the new cell to divide and multiply to develop into an embryo, which is then implanted into the animal's uterus after a certain amount of time (about six days in the case of the Rosslyn Institute's sheep cloning) to impregnate the animal with a genetically identical animal to the one that provided the cell. The animal is then implanted in the uterus of the animal so that it can give birth to an animal that is genetically identical to the donor cell. If the donor cells are genetically modified during this process, the offspring of the asexually reproduced animals will be genetically identical. The main difference between the Honolulu technique, which has produced three generations of cloned mice, and the Dolly the sheep technique is that the genetic material is physically injected directly into the egg cell instead of being grown in a culture. In this process, chemical stimulation is used instead of electrical stimulation to regain control of the egg cell. on July 5, 1998, scientists at the Ishikawa Livestock Production Center and Kinki University's Laboratory of Livestock Science announced the birth of two calves they had cloned from the somatic cells of adult animals. The birth of these two cloned cows demonstrates that the technique of cloning adult animals is reproducible.
When Scotland's Roslin Institute used cloning to clone Dolly the sheep in 1996, the achievement was immediately hailed as one of the century's most significant and controversial technological breakthroughs. The benefits of this breakthrough are obvious. The use of this technology can play a role in the rescue of rare and endangered animals, the replication of good individual livestock, expanding the population of good breed of animals, improve the genetic quality of the herd and production performance, to provide a sufficient number of experimental animals, to promote the study of genetically modified animals, to overcome genetic diseases, the development of high-level new drugs, and the production of internal organs that can be transplanted into human beings, and other research.
While recognizing the positive effects of this technology, people have expressed greater concern about it, he said.
After the identity of the cloned sheep Dolly was disclosed, Oregon scientists in the United States also confirmed that they had already bred monkeys using cloned embryos in August 1996; and there was a legend that a Belgian doctor had already inadvertently cloned a boy. Although the Belgian scientists denied the reports of human cloning, the governments of various countries have attached great importance to the possible legal and ethical implications of cloning technology. The United States, Germany, France, Britain and Canada have set up expert groups to study the issue, and scientists have also demanded that restrictions be imposed on research in this field. The Director-General of the World Health Organization (WHO), Hiroshi Nakajima, and the Commissioner of the European Commission in charge of scientific research issued statements and talks on March 11, 1997, in which they expressed their opposition to human cloning experiments. At present, the more consistent view of all countries on this technology is to enact laws to strengthen the regulation of this technology and to strictly prohibit the use of this technology to clone human beings. The British scientist Wilmut, who cloned Dolly the sheep, also said that the kind of technology used to clone Dolly is extremely inefficient, and before he succeeded in cloning Dolly, the technology had led to the birth of animals with congenital defects. It would be "very inhumane" to use that technique on humans.
The Chinese government also attaches great importance to cloning technology and the related issues it raises, and the State Science and Technology Commission and the Ministry of Agriculture and other departments have convened many seminars and symposiums with the participation of experts from various fields and have reached an understanding of the issues involved. The experts are of the view that the success of animal cloning technology is a major event in scientific research, which has both beneficial aspects and unfavorable possibilities, and that measures must be taken to regulate and strictly control the harmful aspects so that this technology can benefit mankind.
On November 11, 1997, the 29th General Conference of the United Nations Educational, Scientific and Cultural Organization (UNESCO) adopted a document entitled "Universal Declaration on the Human Genome and Human Rights" in Paris, which explicitly rejected the use of human cloning for the reproduction of human beings. The document states that the results of research on the human genome in biology, genetics and medicine should be utilized, but that such research must be aimed at preserving and improving public health, and that practices contrary to human dignity, such as the reproduction of human beings by means of cloning, should not be permitted.
On January 12, 1998, 19 European countries signed a strict ban on human cloning (european protocol on banning human cloning) in Paris, France. This is the first international legal document banning human cloning, and is a supplement to the European Treaty on Biomedicine. The european protocol on banning human cloning prohibits, under penalty of heavy fines, the use of any technology by research institutes or individuals in the signatory countries to create human beings genetically similar to a living or dead person. Researchers and physicians who violate the agreement will be prohibited from conducting research and practising medicine, and the licenses of the research institutes or hospitals concerned will be revoked. Research institutes or individuals from signatory countries will also be held liable if they carry out such activities outside Europe. The agreement was signed by France, Denmark, Lithuania, Finland, Greece, Ireland, Italy, Latvia, Luxembourg, Moldova, Norway, Portugal, Romania, Slovenia, Spain, Sweden, Macedonia, Turkey and San Marino.
Development of cloning technology
Clone, is the translation of Clone, meaning asexual reproduction, cloning technology is asexual reproduction technology. The successful cloning of Dolly the sheep by the Rosslyn Institute in the United Kingdom is the first successful use of somatic cell cloning, which has opened a new page in the history of bioengineering.
Cloning technology has gone through three periods of development:
The first period is microbial cloning, that is, by a bacterium replicated thousands of bacteria and it is exactly the same bacteria and become a bacterial group.
The second period was biotechnological cloning, such as DNA cloning.
The third period is animal cloning, in which an animal is cloned from a single cell.
In nature, there are a number of plants with innate cloning instincts, such as sweet potatoes, potatoes, roses and other plants that reproduce by plugging. The cloning technology of animals, on the other hand, has gone through the development process from embryonic cells to somatic cells. As early as in the 1950s, the United States scientists to amphibians and fish as the object of study, the first cell nuclear transplantation technology, they study the potential for cell development and differentiation, cytoplasm and nucleus of the interaction of the problem. 1986 British scientists Weiladsen first embryonic cells using cell nuclear transplantation method to clone a sheep, and later on, some people have successively cloned cows, sheep, rats, rabbits, monkeys and other animals. The cloning technology in China has also been quite successful. China's cloning technology is also quite successful, in the late 80's, China cloned a rabbit, 1991 Northwest Agricultural University Development Research Institute and the Jiangsu Agricultural College cloning sheep success, 1993 Institute of Developmental Biology of the Chinese Academy of Sciences and the Yangzhou University College of Agriculture *** with a number of cloned goats, 1995 South China Normal University and Guangxi Agricultural University cooperation to clone a cow, followed by the Chinese Academy of Agricultural Sciences, Institute of Animal Husbandry in 1996 Then in 1996, the Institute of Animal Husbandry of the Chinese Academy of Agricultural Sciences succeeded in cloning cattle. The United States has recently succeeded in cloning monkeys, and Japanese scientists have claimed that they have bred more than 200 "cloned cows". All of the above mentioned cloned animals were successfully transplanted using embryonic cells as donor cells.
In February 1997, the Rosslyn Institute in Britain announced the successful cloning of Dolly the sheep, the mammary epithelial cells as the donor cells for cell nuclear transplantation, which opened a new page in the history of biological cloning, a breakthrough in the use of embryonic cells to carry out nuclear transplantation