I. Transgenic technology With the development of human society, humankind has continuously adopted new technologies to increase food production and nutritional value, and increase the economic benefits of producers. Cross-breeding technology has made tremendous contributions to human society and it has produced a large number of excellent cultivars and livestock. The hybrid superiority theory developed after the 1920s has played a remarkable role in agricultural production. With the continuous growth of the population, the demand for agriculture from human society has also continuously increased. The population of the world has surpassed 6 billion in 1999 and is growing at an annual rate of 87 million. It will reach 10 billion in this century. With the continuous growth of the human society and the increase in daily living standards, people are demanding more and more quality of life, require adequate health foods, and have a clean and beautiful living environment. In addition, the production of industrial products that meet the needs of humans has also increased dramatically. The demand for agricultural products, which are mainly derived from agriculture as raw materials, is also increasing. However, with the increase of population and the development of society, the amount of arable land that can provide agricultural products is decreasing. From 0. 44 hectares per capita in 1961 to 0.26 hectares in 1997, the output of agricultural varieties has basically reached production. At the limit, relying on traditional breeding techniques has made it difficult to make major breakthroughs. In recent years, with the development of science and technology, a new concept of "Genetic modified organism" has emerged. Numerous scientists and government officials from all over the world have adopted new organisms derived from genetic engineering as one of the major means of solving future human food. The organisms obtained by the transgenic technology such as transgenic plants, transgenic animals or transgenic microorganisms are generally called genetically modified organisms. This is a new technology developed by scientists in various countries over the past decade on the basis of long-term molecular biology and biotechnology.
Transgenic technology transfers foreign genes into target organisms through special methods to achieve the purpose of transforming organisms. When the transferred gene is integrated into the chromosome or into the genome, it is transmitted to the progeny along with the genetic material of the host organism, and can produce the desired biological function. Transgenic technology is developed on the basis of DNA recombination and explant organization and cell culture. It can break the limitation of relying on traditional breeding methods to use only beneficial genes among related species to transform the organism and realize the benefits of any biological source. The transfer of genes to any organism that needs to be transformed greatly expands the possibilities for humans to transform nature. Scientists recombine genes that have been artificially synthesized or isolated from other organisms, and then recombine them in vitro. They are ligated to appropriate vectors, and they are introduced into the cells of the target organism and inserted into a certain part of the chromosome. Since the rise of genetically modified technology, it has attracted widespread attention and foreshadowed that this technology will make a significant contribution to human well-being in the future of human food, health, the environment, and an in-depth understanding of the nature of life, and then use these knowledge to transform organisms. In recent years, biotechnology companies with genetic transformation as the mainstay have mushroomed. Many chemical companies engaged in the production of pesticides and chemical fertilizers have seen the prospects for the development of biotechnology and have carried out research in the field of biotechnology with the core of genetic transformation. Development, setting off an investment boom.
Second, the purpose and significance of the introduction of foreign genes With the development of biological sciences, the resulting transgenic technology provides people with the understanding of the phenomenon of life, the genetic expression of essential genes, the law of regulation and variability and directional transformation of biological services for human services means.
It can provide genetic control of the growth and development process of research organisms at the gene level; study the function, expression and regulation of related environmental conditions; use the random insertion of foreign genes to study and discover new genes or new gene functions; improve animals The characteristics of plants, plants and microorganisms are better served by agricultural production, biological products industry, fermentation industry and landscaping.
Third, the development process of transgenic technology From genetics, people know that the gene is the material basis of genetics. As early as 1856, Austrian priest Gregor Mendel (1823-1884) discovered the first time in his pea hybrid experiment. Phenomenon, in his "Plant Hybridization Experiment" article, the famous discovery of the trait transfer in pea hybrids was introduced, and the study of the genetics of important disciplines in biology was initiated. In 1911, American scientist Thomas Hunt Morgan proposed genetic theory to control genetic traits in his research on the genetics of fruit fly, although at the time people knew very little about the material basis of genetics. It was not until 1953 that genetics had an important development across the centuries. Two Nobel Prize Winners, James Watson and Francis Crick, proposed the double helix structure theory of genetic material DNA. In the new era of molecular biology, people have carried out fruitful and massive research on genes at the molecular level with great interest, and have obtained a series of exciting research advances in genetics and genes since the history of mankind. In 1972, Paul Berg (1926-) achieved the first in vitro recombination of DNA, allowing people to change the structure, function and expression level of genes according to their own wishes. Because of this contribution in 1980 he won the Nobel Prize in chemistry. Accompanied by the isolation and identification of a large number of genes from microorganisms, animals, plants and humans, they were recombined and modified in vitro. It was possible to recombine genes from different organisms in vitro and transfer them to the target organism. At the same time, animal and plant tissue and cell culture techniques have also developed rapidly since the 1960s. Especially in the field of plants, people have the ability to obtain new whole plants from individual cells under in vitro culture conditions. On the basis of in vitro DNA recombination technology and cell and tissue culture techniques, transgenic technology has become a major research hotspot of biotechnology in the late 1970s. In 1983, three laboratories independently used Agrobacterium as a medium to independently implement transgenic plants. People have clearly seen the huge potential application prospects of genetically modified technology and their value in theoretical research. They have put a lot of manpower and material resources into this field, making the research and development of transgenic plants very fast and gaining a lot of commercial value. Transgenic animal and plant materials. On May 18, 1994, the United States Food and Drug Administration (FDA) formally approved the entry of the "Flavr Savr," a storage-resistant tomato produced by Calgene's transgenic technology, into the U.S. market, opening up new commercialization of transgenic plants. One page.
IV. Status and Prospects of Animal and Plant Transgenesis Plant genetic engineering research has only been a short period of more than 10 years since the 1970s. However, remarkable achievements have been made. The GM crops entered the field test for the first time in the United States and France in 1986. By the end of 1997, the number of field trials of GM crops worldwide had reached 25,000. In 1994, the first transgenic plant, Flavr-Savr, produced by Calgene, was officially approved for production in the United States. In the following few years, the genetically modified varieties of 51 crops such as corn, soybean, cotton, potato, and rapeseed were successively put into commercial use. The 51 crop genetic engineering products included a total of 13 plants, of which maize had the largest number of genetic engineering products. 17 species, which accounted for 33.3% of the total, were mainly soybean, rapeseed, cotton, tomato and other crops.
In 1996, the planting area of ​​transgenic plants in the world reached 1.7 million hectares, 12.8 million hectares in 1997, and 27.8 million hectares in 1998. The area of ​​soybeans was the largest, followed by maize, cotton and rapeseed. Among the genetically modified plants planted in the world in 1997, soybeans had the largest area, reaching 5.1 million hectares, accounting for 40% of the total area; corn 3.2 million hectares, accounting for 25%; tobacco 1.6 million hectares, accounting for 13%; cotton 1.4 million hectares Accounted for 11%; rape was 1.2 million hectares, accounting for 10%. These five crops account for 99% of the total cultivated area of ​​GM crops. In 1999, the United States, the second largest crop of soybeans (accounting for 22% of the country's planted area), had 70% of the planted area of ​​genetically modified soybeans. According to the genetic traits, the crops carrying herbicide-resistance genes accounted for the largest area, reaching 6.9 million hectares in 1997, accounting for 54% of the total area of ​​genetically modified crops; followed by crops with insect-resistance genes, the planting area reached 400 in 1997. Ten thousand hectares, accounting for 31% of the total area; the anti-virus crops are planted on 1.8 million hectares, which is 14%. The countries with the largest area of ​​genetically modified crops in the world are the United States, China, Argentina and Canada, which together account for 99% of the world's genetically modified crops. Among them, the US planted area of ​​genetically modified crops in 1997 reached 8.1 million hectares, accounting for 64% of the world's total area of ​​genetically modified crops; followed by China, the planting area was 1.8 million hectares, which accounted for 14% of the total area; the planting areas in Argentina and Canada were respectively It is 1.4 million hectares and 1.3 million hectares, accounting for 11% and 10% of the world.
The application of genetically modified varieties in production has achieved great economic benefits.
About half of the corn planted in the United States is harmed by European corn borer. The average yield is reduced by 9% and the highest loss is up to 30%. The economic loss caused by this is as much as 1 billion US dollars every year. In 1996, the United States planted 280,000 hectares of Bt genetically modified insect-resistant maize, a 10-fold increase in 1997, a planting area of ​​2.8 million hectares, and 5 million hectares in 1998. According to the results of the 96,97 two-year production data survey, the average yield of insect-resistant corn increased by 9%, equivalent to a net increase of 68.1 US dollars per hectare. The economic benefits of planting insect-resistant maize in the United States in 1996 and 1997 were 19 million and 119 million U.S. dollars, respectively. Transgenic insect-resistant cotton is also a good example. Insect-resistant cotton does not need to be sprayed with pesticides, or only one spray of pesticide is needed to control the main pests; non-transgenic cotton requires 4�6 times. It is estimated that in the United States, about 1 million liters of insecticides were reduced due to planting insect-resistant cotton in 1996, and insect-resistant cotton increased by an average of 7%. The two items together add up to a net income of $175 per hectare of insect-resistant cotton. From this, it is estimated that in the United States in 1996 the increase in economic benefits due to planting insect-resistant cotton was nearly 1.28 billion U.S. dollars. In 1996, the area of ​​planting herbicide-tolerant rape in Canada was 120,000 hectares. In 1997, it surged to 1.2 million hectares, accounting for about 25% of the canola planting area in the same year. It has been estimated that the average yield of herbicide-tolerant oilseed rape is 9% higher than that of the control and that the herbicide-tolerant rapeseed per hectare can increase income by about $50. In 1996, the direct economic benefit of planting herbicide-resistant oilseeds in Canada was 5 million US dollars, and in 1997 it increased to 48 million US dollars. In 1996 and 1997, the United States obtained economic benefits of 1.59 and 3.66 billion U.S. dollars for planting genetically modified crops, respectively. Herbicide-resistant soybeans also have good economic benefits. In 1996, about 400,000 hectares of herbicide-resistant soybeans were planted in the United States and about 100,000 hectares were planted in Argentina. In 1997, the area planted in the United States increased to 3.6 million hectares. In 1998, the planting area reached 12 million hectares, and Argentina increased to 1.4 million hectares. As the herbicide dosage is reduced by an average of 10-40%, huge economic benefits and ecological protection are generated.
The research of genetic engineering in China started comparatively late. Under the support of the national "863" and other high-tech project plans, we have made many important progresses in a short period of more than ten years. In the early 1990s, China's anti-viral transgenic tobacco was first planted in large areas in the field. In 1996, the planting area reached 1 million hectares. In 1997, it increased to 1.6 million hectares. It was once regarded as the world's most genetically modified plant community. The research team led by Professor Guo Sandui of the Biotechnology Center of the Chinese Academy of Agricultural Sciences also achieved good results in the development of insect-resistant cotton. After years of hard work, a batch of transgenic insect-resistant cotton varieties that have been adapted to different production areas have been developed. In 1999, more than 200 million mu were already promoted, creating enormous economic benefits. A large number of transgenic plants, such as aphid-resistant rice cultivars, rice plants resistant to rice planthoppers, rice plants resistant to rice blast, rice plants resistant to bacterial blight, anti-aphid corn, disease-resistant potatoes, and preserved tomatoes, have entered or are about to enter commercial production. In addition, significant progress has also been made in drought-resistant, salt-tolerant transgenic breeding, and the use of transgenic technology to artificially create male sterile breeding materials. The achievement of these achievements fully reflects the wisdom and arduous struggle of our country's scientific and technical workers.
With the expansion of GM crops to other countries, especially developing countries, and the continued expansion of GM crop types and planting areas in China, it is expected that the area of ​​GM crops around the world will increase significantly in the next five years. From the perspective of traits, currently commercialized GM crops are mainly related to herbicide resistance and insect resistance. However, from the current research trends, especially the research and development trends of developed countries, quality-related traits will become more and more important, such as improving the composition of oil crop fats, increasing the content of essential amino acids and proteins, and changing the starch of agricultural products. Quality and content, etc. It is expected that the longer-term development will be in the face of multi-gene control abiotic stress, such as drought-resistant, salt-tolerant and acid-resistant soils. In addition, the superposition of multiple genes for different genes is also a direction for the development of genetic engineering products.
The body of agricultural biotechnology research is turning to private companies. The company's assets of Monsanto, DuPont, and some European Union countries are more than a few ten billion US dollars. With strong capital and research strength, it will certainly occupy an important position in the agricultural biotechnology industrialization market.
Transgenic animals are introduced into the genome of recipient cells by introducing foreign genes into germ cells and early embryonic cells of animals, and then new animal individuals developed from these tissues and cells. In this new individual, each cell is Contains the transferred gene. As early as 1974 Jaenisch et al. transplanted mouse early embryos transformed with the virus SV40 into the uterus of mice and detected the presence of the SV40 gene in the offspring of mice. This is the earliest report about animal transgenesis. In 1980, Gordon first used artificially cloned herpesvirus genes to transform mice with microinjection and successfully obtained transgenic offspring. Since then, reports of animal transgenesis have continued to emerge, causing widespread concern. In particular, the results of Palmert et al.'s study have aroused people's interest in transgenic animals. In their report, it was pointed out that after the rat metalloprotein gene promoter and growth hormone genes were transferred into mice, transgenic offspring that had greatly accelerated growth compared to the control mice were obtained. This result indicates that animal transgenic technology will be Animal breeding plays an encouraging role. In 1985, genetically modified rabbits, sheep and pigs were successively obtained. In 1986 sheep and goats that showed growth hormone gene expression appeared, but did not show significantly faster growth rates than the transgenic mice obtained by Palmerer et al., but the ratio of lean meat and feed conversion increased significantly; Wells et al. Growth hormone gene pigs have significantly increased their growth rate. The above genetically modified experiments are based on fertilized egg injection technology, which has many limitations and affects the rapid development of animal genetic engineering. Evans et al. isolated from mouse blastocysts and then cultured ES cells (embryonic stem cells) in vitro that have similar differentiation capabilities as early embryos. The use of ES cells instead of fertilized eggs allows animal cell culture and genetic transformation experiments to be performed in vitro, which will lead to the development of a new approach to ES cell chimerism in transgenic animals and advance the development of transgenic animals. Later, in the laboratory of Wagner, Lorell-Bdge, Robertson, and Hooper from 1985 to 1987, ES cells were used to transfer exogenous genes into ES cells using retroviral vectors and transgenic animals were obtained. So far, transgenic fish, mice, rats, rabbits, pigs, sheep and cattle have been obtained through the efforts of scientists from various countries. Although our research on transgenic animals started late, we have successfully obtained the above-mentioned transgenic animals, gradually perfected experimental techniques, cultivated talents for genetically modified animals, and served for the further application of genetically modified animals for socialist construction and related basic theories. Research laid a good foundation.
As agricultural biotechnology can provide humans with an unprecedented improvement in the speed and capacity of agricultural and plant varieties, and realize the improvement of the production and quality of animal and plant species and the environment conducive to human habitation in a short period of time, governments and scientific work in countries around the world Both scientists and biotech companies attach great importance to this field and will make this area develop rapidly. The competition among countries will also be fierce.
Transgenic technology transfers foreign genes into target organisms through special methods to achieve the purpose of transforming organisms. When the transferred gene is integrated into the chromosome or into the genome, it is transmitted to the progeny along with the genetic material of the host organism, and can produce the desired biological function. Transgenic technology is developed on the basis of DNA recombination and explant organization and cell culture. It can break the limitation of relying on traditional breeding methods to use only beneficial genes among related species to transform the organism and realize the benefits of any biological source. The transfer of genes to any organism that needs to be transformed greatly expands the possibilities for humans to transform nature. Scientists recombine genes that have been artificially synthesized or isolated from other organisms, and then recombine them in vitro. They are ligated to appropriate vectors, and they are introduced into the cells of the target organism and inserted into a certain part of the chromosome. Since the rise of genetically modified technology, it has attracted widespread attention and foreshadowed that this technology will make a significant contribution to human well-being in the future of human food, health, the environment, and an in-depth understanding of the nature of life, and then use these knowledge to transform organisms. In recent years, biotechnology companies with genetic transformation as the mainstay have mushroomed. Many chemical companies engaged in the production of pesticides and chemical fertilizers have seen the prospects for the development of biotechnology and have carried out research in the field of biotechnology with the core of genetic transformation. Development, setting off an investment boom.
Second, the purpose and significance of the introduction of foreign genes With the development of biological sciences, the resulting transgenic technology provides people with the understanding of the phenomenon of life, the genetic expression of essential genes, the law of regulation and variability and directional transformation of biological services for human services means.
It can provide genetic control of the growth and development process of research organisms at the gene level; study the function, expression and regulation of related environmental conditions; use the random insertion of foreign genes to study and discover new genes or new gene functions; improve animals The characteristics of plants, plants and microorganisms are better served by agricultural production, biological products industry, fermentation industry and landscaping.
Third, the development process of transgenic technology From genetics, people know that the gene is the material basis of genetics. As early as 1856, Austrian priest Gregor Mendel (1823-1884) discovered the first time in his pea hybrid experiment. Phenomenon, in his "Plant Hybridization Experiment" article, the famous discovery of the trait transfer in pea hybrids was introduced, and the study of the genetics of important disciplines in biology was initiated. In 1911, American scientist Thomas Hunt Morgan proposed genetic theory to control genetic traits in his research on the genetics of fruit fly, although at the time people knew very little about the material basis of genetics. It was not until 1953 that genetics had an important development across the centuries. Two Nobel Prize Winners, James Watson and Francis Crick, proposed the double helix structure theory of genetic material DNA. In the new era of molecular biology, people have carried out fruitful and massive research on genes at the molecular level with great interest, and have obtained a series of exciting research advances in genetics and genes since the history of mankind. In 1972, Paul Berg (1926-) achieved the first in vitro recombination of DNA, allowing people to change the structure, function and expression level of genes according to their own wishes. Because of this contribution in 1980 he won the Nobel Prize in chemistry. Accompanied by the isolation and identification of a large number of genes from microorganisms, animals, plants and humans, they were recombined and modified in vitro. It was possible to recombine genes from different organisms in vitro and transfer them to the target organism. At the same time, animal and plant tissue and cell culture techniques have also developed rapidly since the 1960s. Especially in the field of plants, people have the ability to obtain new whole plants from individual cells under in vitro culture conditions. On the basis of in vitro DNA recombination technology and cell and tissue culture techniques, transgenic technology has become a major research hotspot of biotechnology in the late 1970s. In 1983, three laboratories independently used Agrobacterium as a medium to independently implement transgenic plants. People have clearly seen the huge potential application prospects of genetically modified technology and their value in theoretical research. They have put a lot of manpower and material resources into this field, making the research and development of transgenic plants very fast and gaining a lot of commercial value. Transgenic animal and plant materials. On May 18, 1994, the United States Food and Drug Administration (FDA) formally approved the entry of the "Flavr Savr," a storage-resistant tomato produced by Calgene's transgenic technology, into the U.S. market, opening up new commercialization of transgenic plants. One page.
IV. Status and Prospects of Animal and Plant Transgenesis Plant genetic engineering research has only been a short period of more than 10 years since the 1970s. However, remarkable achievements have been made. The GM crops entered the field test for the first time in the United States and France in 1986. By the end of 1997, the number of field trials of GM crops worldwide had reached 25,000. In 1994, the first transgenic plant, Flavr-Savr, produced by Calgene, was officially approved for production in the United States. In the following few years, the genetically modified varieties of 51 crops such as corn, soybean, cotton, potato, and rapeseed were successively put into commercial use. The 51 crop genetic engineering products included a total of 13 plants, of which maize had the largest number of genetic engineering products. 17 species, which accounted for 33.3% of the total, were mainly soybean, rapeseed, cotton, tomato and other crops.
In 1996, the planting area of ​​transgenic plants in the world reached 1.7 million hectares, 12.8 million hectares in 1997, and 27.8 million hectares in 1998. The area of ​​soybeans was the largest, followed by maize, cotton and rapeseed. Among the genetically modified plants planted in the world in 1997, soybeans had the largest area, reaching 5.1 million hectares, accounting for 40% of the total area; corn 3.2 million hectares, accounting for 25%; tobacco 1.6 million hectares, accounting for 13%; cotton 1.4 million hectares Accounted for 11%; rape was 1.2 million hectares, accounting for 10%. These five crops account for 99% of the total cultivated area of ​​GM crops. In 1999, the United States, the second largest crop of soybeans (accounting for 22% of the country's planted area), had 70% of the planted area of ​​genetically modified soybeans. According to the genetic traits, the crops carrying herbicide-resistance genes accounted for the largest area, reaching 6.9 million hectares in 1997, accounting for 54% of the total area of ​​genetically modified crops; followed by crops with insect-resistance genes, the planting area reached 400 in 1997. Ten thousand hectares, accounting for 31% of the total area; the anti-virus crops are planted on 1.8 million hectares, which is 14%. The countries with the largest area of ​​genetically modified crops in the world are the United States, China, Argentina and Canada, which together account for 99% of the world's genetically modified crops. Among them, the US planted area of ​​genetically modified crops in 1997 reached 8.1 million hectares, accounting for 64% of the world's total area of ​​genetically modified crops; followed by China, the planting area was 1.8 million hectares, which accounted for 14% of the total area; the planting areas in Argentina and Canada were respectively It is 1.4 million hectares and 1.3 million hectares, accounting for 11% and 10% of the world.
The application of genetically modified varieties in production has achieved great economic benefits.
About half of the corn planted in the United States is harmed by European corn borer. The average yield is reduced by 9% and the highest loss is up to 30%. The economic loss caused by this is as much as 1 billion US dollars every year. In 1996, the United States planted 280,000 hectares of Bt genetically modified insect-resistant maize, a 10-fold increase in 1997, a planting area of ​​2.8 million hectares, and 5 million hectares in 1998. According to the results of the 96,97 two-year production data survey, the average yield of insect-resistant corn increased by 9%, equivalent to a net increase of 68.1 US dollars per hectare. The economic benefits of planting insect-resistant maize in the United States in 1996 and 1997 were 19 million and 119 million U.S. dollars, respectively. Transgenic insect-resistant cotton is also a good example. Insect-resistant cotton does not need to be sprayed with pesticides, or only one spray of pesticide is needed to control the main pests; non-transgenic cotton requires 4�6 times. It is estimated that in the United States, about 1 million liters of insecticides were reduced due to planting insect-resistant cotton in 1996, and insect-resistant cotton increased by an average of 7%. The two items together add up to a net income of $175 per hectare of insect-resistant cotton. From this, it is estimated that in the United States in 1996 the increase in economic benefits due to planting insect-resistant cotton was nearly 1.28 billion U.S. dollars. In 1996, the area of ​​planting herbicide-tolerant rape in Canada was 120,000 hectares. In 1997, it surged to 1.2 million hectares, accounting for about 25% of the canola planting area in the same year. It has been estimated that the average yield of herbicide-tolerant oilseed rape is 9% higher than that of the control and that the herbicide-tolerant rapeseed per hectare can increase income by about $50. In 1996, the direct economic benefit of planting herbicide-resistant oilseeds in Canada was 5 million US dollars, and in 1997 it increased to 48 million US dollars. In 1996 and 1997, the United States obtained economic benefits of 1.59 and 3.66 billion U.S. dollars for planting genetically modified crops, respectively. Herbicide-resistant soybeans also have good economic benefits. In 1996, about 400,000 hectares of herbicide-resistant soybeans were planted in the United States and about 100,000 hectares were planted in Argentina. In 1997, the area planted in the United States increased to 3.6 million hectares. In 1998, the planting area reached 12 million hectares, and Argentina increased to 1.4 million hectares. As the herbicide dosage is reduced by an average of 10-40%, huge economic benefits and ecological protection are generated.
The research of genetic engineering in China started comparatively late. Under the support of the national "863" and other high-tech project plans, we have made many important progresses in a short period of more than ten years. In the early 1990s, China's anti-viral transgenic tobacco was first planted in large areas in the field. In 1996, the planting area reached 1 million hectares. In 1997, it increased to 1.6 million hectares. It was once regarded as the world's most genetically modified plant community. The research team led by Professor Guo Sandui of the Biotechnology Center of the Chinese Academy of Agricultural Sciences also achieved good results in the development of insect-resistant cotton. After years of hard work, a batch of transgenic insect-resistant cotton varieties that have been adapted to different production areas have been developed. In 1999, more than 200 million mu were already promoted, creating enormous economic benefits. A large number of transgenic plants, such as aphid-resistant rice cultivars, rice plants resistant to rice planthoppers, rice plants resistant to rice blast, rice plants resistant to bacterial blight, anti-aphid corn, disease-resistant potatoes, and preserved tomatoes, have entered or are about to enter commercial production. In addition, significant progress has also been made in drought-resistant, salt-tolerant transgenic breeding, and the use of transgenic technology to artificially create male sterile breeding materials. The achievement of these achievements fully reflects the wisdom and arduous struggle of our country's scientific and technical workers.
With the expansion of GM crops to other countries, especially developing countries, and the continued expansion of GM crop types and planting areas in China, it is expected that the area of ​​GM crops around the world will increase significantly in the next five years. From the perspective of traits, currently commercialized GM crops are mainly related to herbicide resistance and insect resistance. However, from the current research trends, especially the research and development trends of developed countries, quality-related traits will become more and more important, such as improving the composition of oil crop fats, increasing the content of essential amino acids and proteins, and changing the starch of agricultural products. Quality and content, etc. It is expected that the longer-term development will be in the face of multi-gene control abiotic stress, such as drought-resistant, salt-tolerant and acid-resistant soils. In addition, the superposition of multiple genes for different genes is also a direction for the development of genetic engineering products.
The body of agricultural biotechnology research is turning to private companies. The company's assets of Monsanto, DuPont, and some European Union countries are more than a few ten billion US dollars. With strong capital and research strength, it will certainly occupy an important position in the agricultural biotechnology industrialization market.
Transgenic animals are introduced into the genome of recipient cells by introducing foreign genes into germ cells and early embryonic cells of animals, and then new animal individuals developed from these tissues and cells. In this new individual, each cell is Contains the transferred gene. As early as 1974 Jaenisch et al. transplanted mouse early embryos transformed with the virus SV40 into the uterus of mice and detected the presence of the SV40 gene in the offspring of mice. This is the earliest report about animal transgenesis. In 1980, Gordon first used artificially cloned herpesvirus genes to transform mice with microinjection and successfully obtained transgenic offspring. Since then, reports of animal transgenesis have continued to emerge, causing widespread concern. In particular, the results of Palmert et al.'s study have aroused people's interest in transgenic animals. In their report, it was pointed out that after the rat metalloprotein gene promoter and growth hormone genes were transferred into mice, transgenic offspring that had greatly accelerated growth compared to the control mice were obtained. This result indicates that animal transgenic technology will be Animal breeding plays an encouraging role. In 1985, genetically modified rabbits, sheep and pigs were successively obtained. In 1986 sheep and goats that showed growth hormone gene expression appeared, but did not show significantly faster growth rates than the transgenic mice obtained by Palmerer et al., but the ratio of lean meat and feed conversion increased significantly; Wells et al. Growth hormone gene pigs have significantly increased their growth rate. The above genetically modified experiments are based on fertilized egg injection technology, which has many limitations and affects the rapid development of animal genetic engineering. Evans et al. isolated from mouse blastocysts and then cultured ES cells (embryonic stem cells) in vitro that have similar differentiation capabilities as early embryos. The use of ES cells instead of fertilized eggs allows animal cell culture and genetic transformation experiments to be performed in vitro, which will lead to the development of a new approach to ES cell chimerism in transgenic animals and advance the development of transgenic animals. Later, in the laboratory of Wagner, Lorell-Bdge, Robertson, and Hooper from 1985 to 1987, ES cells were used to transfer exogenous genes into ES cells using retroviral vectors and transgenic animals were obtained. So far, transgenic fish, mice, rats, rabbits, pigs, sheep and cattle have been obtained through the efforts of scientists from various countries. Although our research on transgenic animals started late, we have successfully obtained the above-mentioned transgenic animals, gradually perfected experimental techniques, cultivated talents for genetically modified animals, and served for the further application of genetically modified animals for socialist construction and related basic theories. Research laid a good foundation.
As agricultural biotechnology can provide humans with an unprecedented improvement in the speed and capacity of agricultural and plant varieties, and realize the improvement of the production and quality of animal and plant species and the environment conducive to human habitation in a short period of time, governments and scientific work in countries around the world Both scientists and biotech companies attach great importance to this field and will make this area develop rapidly. The competition among countries will also be fierce.
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