The idea of cloning technology was first put forward by German embryologist in 1938. 1952, scientists first carried out cloning experiments with frogs, and then people continued to study cloning technology with various animals. Because of the little progress in this technology, the research work once entered a trough in the early 1980 s, and later some people cloned it successfully with mammalian embryonic cells. 1July 5, 996, British scientist Ian? Dr. Wilmut cloned a live sheep from adult sheep somatic cells, which brought a major breakthrough to the research of cloning technology. It broke through the technical difficulty that only embryonic cells could be used for animal cloning in the past, and achieved the goal of animal cloning with somatic cells for the first time, realizing animal replication in a higher sense. The goal of studying cloning technology is to find a better way to change the genetic composition of domestic animals and cultivate animal groups that can provide consumers with better food or any chemicals they may need.
The basic process of cloning is to transplant the nucleus of a donor cell containing genetic material into an enucleated egg cell, then fuse the two cells into a whole by micro-current, and then promote the new cell to divide and reproduce and develop into an embryo. When the embryo develops to a certain extent (it takes about 6 days for Roslin Institute to clone sheep), it is implanted into the uterus of an animal to make the animal pregnant and give birth to an animal with the same gene as the donor. In this process, if the donor cells are genetically modified, the genes of the offspring of asexual animals will also change in the same way. The main difference between "Honu Lu Lu badminton technology" and Dolly sheep technology that successfully bred three generations of cloned mice is that the genetic material in the cloning process is directly injected into the egg cells by physical methods, rather than cultivated in the culture medium. In this process, the egg cells are controlled again by chemical methods instead of electrical methods. 1On July 5th, 998, scientists from Ishikawa Animal Husbandry Center and Animal Husbandry Laboratory of Feng Jingen University announced that two calves cloned from adult animal somatic cells were born. The birth of these two cloned cows shows that the technology of cloning adult animals is repeatable.
1996 When Dolly was cloned by Roslin Institute in Scotland, this achievement was immediately hailed as one of the most important and controversial scientific and technological breakthroughs in this century. The benefits of this breakthrough are obvious. This technology can play an important role in rescuing rare and endangered animals, replicating excellent livestock individuals, expanding and improving animal populations, improving the genetic quality and production performance of herds, providing enough experimental animals, promoting the research of transgenic animals, overcoming genetic diseases, developing high-level new drugs, and producing internal organs for human transplantation.
While affirming the positive role of this technology, people also expressed their concerns about this technology to a greater extent. Hey? Bad looks? What is the purpose of the temple? The popularization of this asexual reproduction technology in animal husbandry is likely to destroy the ecological balance and lead to the large-scale spread of some diseases; If it is applied to human reproduction, there will be a huge ethical crisis.
After Dolly the sheep's identity was revealed, scientists in Oregon in the United States also confirmed that they had bred monkeys from cloned embryos in August 1996. There is also a legend that a doctor in Belgium accidentally cloned a boy. Although Belgian scientists deny the report of human cloning, all countries attach great importance to the possible legal and ethical impact of cloning technology. The United States, Germany, France, Britain, Canada and other countries have set up expert groups to study this issue, and scientists also demand that research in this field be restricted. Nakajima Hiroshi, Director-General of the World Health Organization, and the Scientific Research Committee of the European Commission1March 997 1 1 made statements and talks respectively, expressing their opposition to human cloning experiments. At present, countries have a consensus on this technology, that is, laws should be enacted to strengthen the management of this technology, and it is strictly forbidden to use it to copy human beings. Cloning Dolly Sheep ... >>
Question 2: What is human cloning? Cloning is defined as an independent cell propagation line, which means that offspring are completely copied from one cell and have exactly the same genetic material.
A bacterium can split in two after about 20 minutes; A grape branch cut into ten segments may become ten grapes; Cactus is cut into several pieces, and each piece takes root when it hits the ground; A strawberry can grow hundreds of strawberry seedlings a year by its creeping stolons ... all these are the reproduction of offspring by an organism by splitting itself in two or expanding a small part of itself. This reproduction is called asexual reproduction. The English name of asexual reproduction is "Clone", transliterated as "Clone". In fact, the word "clone" in English comes from the Greek word "clone". Today, the meaning of "cloning" is not only "asexual reproduction", but also refers to a group of individuals who have undergone asexual reproduction from an ancestor.
This group of asexual offspring from an ancestor is also called "asexual cloning", or cloning for short. Many animals in nature, under normal circumstances, rely on male cells (* * *) produced by their fathers and female cells (eggs) produced by their mothers to fuse (fertilize) into fertilized eggs (zygotes), and then the fertilized eggs develop into embryos through a series of cell division, and finally form new individuals. This kind of reproduction mode, which relies on both parents to provide sex cells and produces offspring through the fusion of bisexual cells, is called sexual reproduction. If we divide an embryo into two, four and eight pieces by surgery, and finally make an embryo grow into two, four and eight creatures by special methods, these creatures will clone individuals. These two, four and eight individuals are called asexual cloning (also called cloning).
Cloning is a transliteration of the English word Clone, which means asexual cloning, that is, a group that can be inherited continuously through asexual reproduction (such as mitosis), and is often used to describe cloning at the cell level. Cloning refers to the technical operation of obtaining the target gene or cell from numerous genes or cell groups through asexual reproduction and selection.
Generation and technology of cloned sheep
Mammalian cloning is the application of the concept of cloning at the individual level, that is, animal individuals or groups produced through asexual reproduction, which have exactly the same genetic background. Identical twins have the same genetic background, but they come from sexual reproduction, that is, they are developed from fertilized eggs. The individual genetic background produced by the same embryo segmentation is the same, but it comes from undifferentiated pluripotent embryonic stem cells and is a continuation of sexual reproduction. The genetic background of a real cloned individual is the same as that of a single donor, and its genetic material should come from differentiated somatic cells, not embryonic cells. Mammalian individual cloning technology is the combination and optimization of various cell engineering technologies. Firstly, the egg is collected, and the nucleus and cytoplasm are separated by micro-operation, so that the egg loses its original genetic material and only the cytoplasm is left; Secondly, the nucleus of donor breast tissue cells was transplanted into seedless egg cells by cell fusion technology. Nuclear-cytoplasmic fusion eggs were cultured in vitro to develop into early embryos and transplanted into the uterus of pseudopregnant mothers to develop into individuals. At least nuclear-cytoplasmic separation, cell fusion, in vitro culture and embryo transfer are used here, and they must be closely related and fully optimized.
Cell cloning technology
Source: Public Science and Technology Network
Cell cloning technology, the formal biological term is cell culture technology. Cell culture is an indispensable process for the whole bioengineering technology or one of the biological cloning technologies, and cell culture itself is a large-scale cloning of cells. Cell culture includes not only microbial cells, but also animal and plant cells and animal and plant tissues.
Cell culture technology can transform a cell into a simple single cell or multi-cell with little differentiation after a large number of cultures, which is an essential link of cloning technology, and cell culture itself is cell cloning. A large number of cells or their metabolites are obtained by cell culture. Because biological products are all derived from cells, it can be said that cell culture technology is the most core and basic technology in biotechnology.
The growth of cells needs a certain nutritional environment, and the nutrient matrix used to maintain cell growth is called culture medium. According to the physical state, media can be divided into liquid media and solid media. Liquid culture medium is used in large-scale industrial production and research on basic theories such as physiological metabolism. Liquid culture medium is made by adding some coagulant (such as agar) or solid culture (such as bran and rice). Solid culture medium provides nutrition for the growth of cells. & gt
Question 3: What is cloning technology? Cloning technology is asexual reproduction technology. Usually, sexual reproduction includes mating between males and females, combining with eggs to develop embryos and producing new individuals after pregnancy. Cloning technology does not require mating between males and females, and does not require the combination of * * and eggs. It only needs to extract single cells from animals, cultivate them into embryos by artificial methods, and then implant the embryos into female animals to breed new individuals. This cloned animal cultured with single cells has exactly the same characteristics as the single-cell donor and is a "replica" of the single-cell donor. Scientists in Britain and Oregon in the United States have successively cultivated "cloned sheep" and "cloned monkeys". The success of cloning technology is called "historic event and scientific innovation". Some people even think that cloning technology can be compared with the advent of the atomic bomb that year.
Question 4: What is cloning technology? Cloning is a transliteration of the English word "clone", which has three different meanings in the field of biology.
1. At the molecular level, cloning generally refers to DNA cloning (also called molecular cloning). It refers to inserting specific DNA fragments into vectors (such as plasmids and viruses) by recombinant DNA technology, and then replicating in host cells to obtain a large number of identical DNA fragments "groups".
2. At the cellular level, cloning is essentially a cell group formed by the division of a single ancestor cell. These cells all have the same gene. For example, a cell group with the same genetic background formed by dividing a cell in vitro culture medium for several generations is a cell clone. For another example, in vertebrates, when foreign substances (such as bacteria or viruses) invade, specific recognition antibodies will be produced through immune response. All plasma cells that produce specific antibodies are formed by B cell division, and such plasma cell groups are also cell clones. Cell cloning is a low-level reproductive mode-asexual reproduction, that is, offspring and parents have the same heredity and do not need sexual union. The lower the level of biological evolution, the more likely it is to adopt this mode of reproduction.
3. At the individual level, cloning refers to a group of two or more individuals with the same genotype. For example, two identical twins are a clone! Because they come from the same egg cell, their genetic background is exactly the same. According to this definition, "Dolly" cannot be said to be a clone! Because "Dolly" is just a lonely one. Only when two or more identical nuclei are transplanted into two or more identical enucleated eggs and two or more dollies with identical genetic background are obtained can the British embryologists use the word cloning to describe them. Therefore, in the sensational paper published in Nature from 65438 to February 1997, the author did not describe Dolly as a clone.
Question 5: Who invented cloning technology, Ian? Wilmut
Question 6: What is cloning? Cloning is a transliteration of the English word "clone", which is generally translated as transplanting or copying in Taiwan Province Province, Hongkong and Macau. It is a process of using biotechnology to produce offspring that are exactly the same as the original individual genome through asexual reproduction.
Cloning is usually artificially induced asexual reproduction or natural asexual reproduction (such as plants). Cloning is a multicellular organism, genetically identical to another organism. Clones can be natural clones, such as asexual reproduction or individuals with identical genes (just like identical twins). But what we usually mean by cloning is an identical copy produced by conscious design.
The cloned English word "clone" comes from the Greek word "kl! N "(twig). In horticulture, the word "clone" was used until the 20th century. Later, sometimes "e" is added to the end of the word to become "clone" to indicate that the pronunciation of "o" is a long vowel. Recently, with the widespread use of this concept and word in public life, spelling has been limited to the use of "cloning". The Chinese translation of this word is transliterated as "clone" in Chinese mainland, but it is often translated as "copy" in Hong Kong and Taiwan. The former "clone" is like the transliteration "copy" of copy, which has the disadvantage of not looking at the meaning of the text; The latter "copy" can roughly express the meaning of cloning, but it is inaccurate and easy to misunderstand.
In biology, cloning is usually used in two aspects: cloning a gene or cloning a species. Cloning a gene refers to obtaining a gene from one individual (for example, by PCR), then inserting it into another individual (usually by vector), and then studying or utilizing it. Cloning sometimes refers to the successful identification of a gene with a certain phenotype. So when a biologist says that the gene of a disease has been cloned successfully, that is to say, the position and DNA sequence of this gene have been determined. Obtaining a copy of this gene can be considered as a by-product of identifying this gene.
Cloning an organism means creating a new object with exactly the same genetic information as the original organism. Under the background of modern biology, this usually includes somatic cell nuclear transfer. In somatic cell nuclear transfer, the nucleus of oocytes is removed and replaced by the nucleus taken from cloned organisms. Usually, oocytes and their transplanted nuclei should come from the same species. Because the nucleus contains almost all the genetic information of life, the host oocyte will develop into an organism genetically the same as the nuclear donor. Although mitochondrial DNA has not been transplanted here, it is still relatively rare, and its impact on organisms can usually be ignored.
In horticulture, cloning refers to the offspring of a single plant produced by vegetative propagation. Many plants obtain a large number of offspring from one plant by cloning this asexual reproduction.
Cloning progress
Modern cloning techniques, including nuclear transfer, have been successfully tested in some species (in chronological order):
Frog: 1962, unsuccessful.
Carp: 1963, China scientist Tong Dizhou successfully cloned a female carp by inserting the DNA of a male carp into the egg of a female carp as early as 1963, which was 33 years earlier than Dolly's cloning. However, because the related papers were published in a China sci-tech journal and were not translated into English, they are not well-known internationally. (From: Public Broadcasting Company)
Sheep: 1996, Dolly
Macaque: Tetra, female, June 5438 +2000 10.
Pigs: in March 2000, 5 Scottish PPL piglets; August, Xena, female
Cattle: 200 1 year, alpha and beta, male.
Cat: 200 1 ending, plagiarist (CC), female.
Mouse: In 2002
Rabbit: It was independently realized in France and South Korea from March to April, 2003;
Mule: May 2003, Gem, Idaho, male; June, Utah pioneer, male
Deer: Dewey in 2003.
Ma: Prometea, female, 2003.
Dog: 2005, experimental team of Seoul National University, South Korea, Snaby.
Although great progress has been made in cloning research, the success rate of cloning is still quite low: before Dolly was born, researchers experienced 276 failed attempts; After 9000 attempts, 70 calves were born, and one third of them died at an early age. Prometea also made 328 attempts to be born successfully. For ... >>
Question 7: What is cloning technology? Cloning technology is asexual reproduction technology. Usually, sexual reproduction includes mating between males and females, combining with eggs to develop embryos and producing new individuals after pregnancy. Cloning technology does not need male and female mating, and does not need to combine with eggs. It only needs to extract single cells from animals, cultivate them into embryos by artificial methods, and then implant the embryos into female animals to breed new individuals. This cloned animal cultured with single cells has exactly the same characteristics as the single-cell donor and is a "replica" of the single-cell donor. Scientists in Britain and Oregon in the United States have successively cultivated "cloned sheep" and "cloned monkeys". The success of cloning technology is called "historic event and scientific innovation". Some people even think that cloning technology can be compared with the advent of the atomic bomb that year.
Question 8: Where is cloning technology applied? Cloning technology and medicine In modern times, doctors can transplant almost all human organs and tissues. But as far as science and technology are concerned, rejection in organ transplantation is still the most troublesome. The reason of rejection is poor compatibility due to tissue mismatch. If the organs of "clones" are provided to "hominids" for organ transplantation, there is no need to worry about rejection at all, because the genes and tissues of the two are matched. The question is, is it humane to use "clones" as organ donors? Is it legal? Is it economical? Cloning technology can also be used to multiply valuable genes. For example, in medicine, people produce insulin to treat diabetes, growth hormone to make dwarfism patients grow taller again, fibrinolytic enzyme to resist various virus infections and so on through "cloning" technology. Cloning technology is asexual reproduction technology. Usually, sexual reproduction includes mating between males and females, combining with eggs to develop embryos and producing new individuals after pregnancy. Cloning technology does not require mating between males and females, and does not require the combination of * * and eggs. It only needs to extract single cells from animals, cultivate them into embryos by artificial methods, and then implant the embryos into female animals to breed new individuals. This cloned animal cultured with single cells has exactly the same characteristics as the single-cell donor and is a "replica" of the single-cell donor. Scientists in Britain and Oregon in the United States have successively cultivated "cloned sheep" and "cloned monkeys". The success of cloning technology is called "historic event and scientific innovation". Some people even think that cloning technology can be compared with the advent of the atomic bomb that year. Cloning technology can be used to produce "cloned human" and "cloned human", which has aroused widespread concern all over the world. Is cloning sad or happy, a curse or a blessing for human beings? Materialist dialectics holds that everything in the world is a contradictory unity, which is divided into two parts. So is cloning technology. If we use cloning technology to "copy" a war madman like Hitler, what will it bring to human society? Even if it is used to "copy" ordinary people, it will bring a series of ethical problems. If cloning technology is applied to animal husbandry production, it will make fundamental changes in the cultivation and reproduction of excellent livestock breeds. If cloning technology is used in the research of gene therapy, it is very possible to overcome the persistent diseases that endanger human life and health, such as cancer and AIDS. Cloning technology, like atomic energy technology, is a double-edged sword with the hilt in human hands. Human beings should take joint action to avoid the emergence of "human cloning" and let cloning technology benefit human society. Cloning refers to a genetically homogeneous biological population produced by asexual reproduction, that is, a group of cells or biological individuals with identical genetic components. Cloning means "branches and leaves of small trees" in Greek, which means asexual reproduction. Now it refers to asexual breeders at different levels such as individuals, cells and genes. (1) Individual level: In the asexual reproduction of plants, the individual groups such as germination and cutting which are grown by the same individual through asexual reproduction are regarded as clones. Through tissue culture, plant cells can be cultured and developed into complete individuals (calli). Individuals with the same genotype obtained by this method are also called clones. In the asexual reproduction of animals, a typical example is the experimental method of nuclear transfer, that is, the nucleus of differentiated cells is transplanted into a frog egg which has been enucleated in advance, so that it can develop and obtain a cloned frog. Cloned animals have homogeneous genetic characteristics and are important experimental materials for studying the influence of environmental conditions on development and differentiation and drug detection. In mammals, due to cell differentiation, the degree of nuclear heterogeneity is aggravated, so there is no successful example of nuclear transplantation. (2) Cell level: The cell group produced by mitosis of a cell is called clone. However, if the cultured cells are transformed, it is easy to cause chromosome variation. (3) Gene level: It is possible to obtain a uniform genome by combining a specific gene with a vector and propagating it in a host such as bacteria. Cloning gene has been applied to the basic research on the relationship between gene function and fine structure and the production of useful substances. At the above three levels, the proliferation and separation of a single clonal population is called cloning. At this point, the word clone can also be understood as a verb. Cloning is the core part of recombinant DNA technology. In fact, cloning technology has been used to propagate viruses, other microorganisms and pure plants through nutrition, thus ensuring the accurate continuity of the genomes of these organisms. Now, the word clone also includes a single >>
Question 9: What is cloning technology? Cloning technology-an epoch-making impact
1On February 22nd, 997, Wilmut, a scientist from Roslin Institute in England, and others announced the success of cloning sheep with somatic cells, which caused great shock in the world. For a time, Dolly the cloned sheep became the most dazzling "star" in the animal kingdom, and its "baa baa" sound quickly spread all over the world.
"Clone" is a transliteration of the English word "clone", which itself means asexual reproduction, that is, a pure cell line formed by the division and reproduction of the same ancestor cells, and each cell in this cell line has the same genes.
Cloning technology is called "biomagnification technology" in modern biology, which has gone through three development periods: the first period is microbial cloning, that is, a bacterium quickly replicates thousands of identical bacteria and becomes a bacterial colony; The second period is biotechnology cloning, such as cloning with genetic gene DDDNA; The third period is animal cloning, that is, cloning a cell into an animal. Dolly the cloned sheep was cloned from the somatic cells of ewe by animal cloning technology.
In nature, many plants have innate cloning instinct, such as sweet potatoes, potatoes, roses and other cutting propagation plants. However, animal cloning technology has experienced the development process from embryonic cells to somatic cells.
As early as 1950s, American scientists took amphibians and fish as research objects and pioneered nuclear transplantation technology. 1986, British scientist Wila Anderson cloned a sheep with embryonic cells. Later, some people cloned animals such as cows, mice, rabbits and monkeys. By using embryonic cells as donor cells for nuclear transfer, the birth of these cloned animals was successful.
Dolly the cloned sheep used mammary epithelial cells (somatic cells) as donor cells for nuclear transfer, which turned a new page in the history of biological cloning, broke through the traditional way of nuclear transfer using embryonic cells and made great progress in cloning technology.
Dolly the cloned sheep has no father, only three mothers. The whole cloning process is as follows:
First, scientists took an ordinary cell from the mammary gland of a 6-year-old Dorset ewe A (Dolly's biological mother) from Finland, and isolated the gene of this cell for later use.
Then, scientists take out the unfertilized egg cell of another ewe B (Dolly's borrowed mother), take out the gene in this egg cell, and replace it with the gene of the mammary gland cell of ewe B to form an egg cell containing new residues, and then activate this gene through the discharge of the "switched" egg cell to promote its division and development into an embryo.
Finally, the embryo grew to a certain extent, implanted into the uterus of the third ewe C (Dolly's surrogate mother), and gave birth to Dolly through normal pregnancy.
Dolly completely inherited all the DNA genetic characteristics of her biological mother DD Dorset ewe, and was a 100% copy of Dorset ewe.
The phenomenon of asexual reproduction exists in lower plants, but according to the law of the mammalian world, animal reproduction should be completed by bisexual germ cells. Because the genetic material of father and mother accounts for half of the offspring, the offspring is definitely not a copy of their parents. The birth of cloned sheep means that human beings can produce the same life in large quantities with one cell of mammals, completely breaking the eternal laws of nature. This is a milestone in the development history of bioengineering technology and a major scientific breakthrough in human history.
Cloning technology is known as "inexhaustible gold mine", which is of great significance in production practice and has great potential economic value. First of all, in the utilization of animal heterosis, compared with conventional methods, mammalian cloning technology takes less time, and the selected breeding stocks are stable; Secondly, cloning technology can play an important role in saving endangered rare species and protecting biodiversity. Even if the success rate of natural mating is low, researchers can choose suitable somatic cells from endangered rare animals for asexual reproduction, thus effectively protecting these species.
The great breakthrough of animal cloning technology has also brought widespread controversy. Cloning technology is a double-edged sword for human beings. On the one hand, it can bring many benefits to human beings, such as maintaining excellent varieties, saving endangered animals, and using the same genetic background of cloned animals for biomedical research. & gt
Question 10: What is cloning technology? Cloning is a transliteration of the English word "clone", which has three different meanings in the field of biology.
1. At the molecular level, cloning generally refers to DNA cloning (also called molecular cloning). It refers to inserting specific DNA fragments into vectors (such as plasmids and viruses) by recombinant DNA technology, and then replicating in host cells to obtain a large number of identical DNA fragments "groups".
2. At the cellular level, cloning is essentially a cell group formed by the division of a single ancestor cell. These cells all have the same gene. For example, a cell group with the same genetic background formed by dividing a cell in vitro culture medium for several generations is a cell clone. For another example, in vertebrates, when foreign substances (such as bacteria or viruses) invade, specific recognition antibodies will be produced through immune response. All plasma cells that produce specific antibodies are formed by B cell division, and such plasma cell groups are also cell clones. Cell cloning is a low-level reproductive mode-asexual reproduction, that is, offspring and parents have the same heredity and do not need sexual union. The lower the level of biological evolution, the more likely it is to adopt this mode of reproduction.
3. At the individual level, cloning refers to a group of two or more individuals with the same genotype. For example, two identical twins are a clone! Because they come from the same egg cell, their genetic background is exactly the same. According to this definition, "Dolly" cannot be said to be a clone! Because "Dolly" is just a lonely one. Only when two or more identical nuclei are transplanted into two or more identical enucleated eggs and two or more dollies with identical genetic background are obtained can the British embryologists use the word cloning to describe them. Therefore, in the sensational paper published in Nature from 65438 to February 1997, the author did not describe Dolly as a clone.
The most beautiful family story material article 1
Zhang Qiaoyun, female, 1985, born in July, is a villager of Dakezu Village, Xingang Town