Genetically modified food "is a new term. Some people say that "2 1 century is the century of biotechnology", and genetically modified food is the product of biotechnology. Using modern molecular biotechnology, the genes of some organisms are transferred to other species, so that the genetic material of organisms can be transformed into the expected goals in terms of traits, nutritional quality and consumption quality. Foods directly eaten by genetically modified organisms or produced as processing raw materials are collectively referred to as "genetically modified foods". In fact, the basic principle of transgene is not difficult to understand, which is similar to conventional cross breeding. Hybridization is to transfer the whole gene chain (chromosome), and gene transfer is to select the most useful short gene transfer. Therefore, transgene has higher selectivity than hybridization. What kinds of genetically modified foods are there? In order to improve the nutritional value of agricultural products and produce food more quickly and efficiently, scientists use transgenic methods to change the genetic information of organisms and assemble new genes, so that future crops have the characteristics of high nutrition, storage resistance, pest resistance and herbicide resistance, and constantly produce new genetically modified foods. The first category, plant genetically modified food. There are many genetically modified foods from plants. For example, bread production needs wheat with high protein content, while the current wheat variety protein has low content. Transferring the highly expressed protein gene into wheat will make bread have better baking performance. Tomato is a kind of fruit and vegetable with rich nutrition and high economic value, but it is not resistant to storage. In order to solve the storage problem of tomatoes and other fruits, researchers found that the enzyme gene that controls the ethylene synthesis of plant aging hormone is an important gene that leads to plant aging. If the expression of this gene can be inhibited by genetic engineering and the biosynthesis of ethylene, an aging hormone, can be controlled, tomatoes will not become soft and rotten easily. Many scientists from the United States, China and other countries have cultivated this new tomato variety through their efforts. This tomato is anti-aging, anti-softening, storage-resistant, and can be transported for a long distance, which can reduce the waste in processing, production and transportation. The second category is animal genetically modified food. There are also many kinds of animal genetically modified foods. For example, human genes are transferred to cattle, and the milk produced by cows when they grow up contains genetic drugs, which can be used to treat human diseases after extraction. By transferring the human auxin gene into the genome of pigs, the growth rate of pigs has doubled and the quality of pork has been greatly improved. Now such pork is invited to the table in Australia. The third category, genetically modified microbial food. Microorganisms are the most commonly used transformation materials for transgene, so transgenic microorganisms are relatively easy to cultivate and widely used. For example, chymosin used to be extracted only from the stomachs of killed calves. Nowadays, transgenic microorganisms can be produced in large quantities in vitro, which avoids the innocent death of calves and reduces the production cost. The fourth category, genetically modified special food. Scientists use biological genetic engineering to turn ordinary crops such as vegetables, fruits and grain into magical "vaccine food", which can prevent diseases. Scientists have cultivated an alfalfa plant that can prevent cholera. Feeding this alfalfa to mice can greatly enhance their disease resistance. Moreover, this cholera antigen can withstand the corrosion of gastric acid without being destroyed, which can stimulate the body's immune ability to cholera. Therefore, more and more disease-resistant genes are transferred to plants, so that people can taste delicious fresh fruits and achieve the purpose of preventing diseases. Is it safe to eat genetically modified food? Genetically modified food is a product created by new technology and a new thing. People naturally ask, is it safe to eat genetically modified food? In fact, it was Professor Puppet from Aberdeen Roth Institute in Britain who first raised this question. From 65438 to 0998, he found that the internal organs and immune system of young rats would be damaged after eating genetically modified potatoes. This has aroused great concern in the scientific community. Then, the Royal Society reviewed the report and announced in May 1999 that the study was "full of loopholes". From 65438 to 0999, Nature, an authoritative British scientific magazine, published a paper by john rossi, a professor at Cornell University in the United States, pointing out that beneficial insects in the field, such as butterfly larvae, will be stunted after eating leaves sprinkled with some transgenic corn pollen, and the mortality rate is particularly high. At present, there is still some evidence to point out the potential dangers of genetically modified foods. But more scientists' experiments show that genetically modified food is safe. Scientists who agree with this view mainly have the following reasons. First of all, any kind of genetically modified food has gone through a lot of scientific experiments before it goes on the market. The state and the government have relevant laws and regulations to restrain them, and scientists also have a very strict academic attitude. In addition, farmers will use pesticides to ensure the quality when planting traditional crops, while some insect-resistant genetically modified foods do not need to be sprayed with pesticides. Also, whether a food can cause poisoning depends mainly on whether it has receptors in the human body and whether it can be metabolized. After screening, the transformed genes have clear functions, so the transgenic components will not accumulate in the human body, so there will be no harm. For example, an insect-resistant corn cultivated by us, which is transformed into corn with the gene of Bacillus thuringiensis, can only lead to the death of LEPIDOPTERA insects, because only LEPIDOPTERA insects have the specific receptor of protein encoded by this gene, while humans and other animals and insects do not have this receptor, so there is no toxic effect. In 1993, OECD put forward the evaluation principle of genetically modified food for the first time-the principle of "substantial equivalence", that is, if the types and contents of various main nutritional components, main anti-nutritional substances, toxic substances and allergic components of genetically modified food are analyzed and determined, they are considered to be substantially equivalent and there is no safety problem; If there is no substantial equivalence, it is necessary to evaluate the security one by one. In China, the State Science and Technology Commission promulgated the Safety Management Measures of Genetic Engineering on 1993 to guide the research and development of genetic engineering in China. In 2000, led by the State Environmental Protection Administration, with the participation of eight relevant departments, China National Biosafety Framework was formulated. Development Status of Genetically Modified Foods In recent ten years, the development of modern biotechnology has shown great potential in agriculture, and has gradually developed into an industry that can generate huge social and economic benefits. From 65438 to 0999, transgenic plants were planted in 12 countries in the world, covering an area of 39.9 million hectares. Among them, the United States is a big planting country, accounting for 72% of the global planting area. Many countries in the world regard modern biotechnology as the key area of national priority development, and invest a lot of manpower, material resources and financial resources to support the development of biotechnology. However, the development of genetically modified foods in various countries and regions of the world is uneven. For example, Americans have a deeper experience of biotechnology. Genetically modified food has not been rejected more in the United States, but has stepped onto the table of ordinary people. In recent years, there are more and more varieties of genetically modified crops in the United States, and the planting area has increased year by year. The planting area of genetically modified corn in the United States increased from 1996 to 160000 hectares, and reached 103000 hectares in 2000, accounting for about half of the planting area of corn in the United States. Genetically modified soybeans are also used to make hundreds of foods, including cooking oil, candy and margarine. China has a population of/kloc-0.3 billion, accounting for 22% of the world's total population, which means that China will feed 22% of the world's population with 7% of the world's arable land. With the development of urbanization, agricultural arable land is decreasing, while the population is increasing, so there is a higher demand for industrial and agricultural production and greater pressure on the environment. Therefore, since the early 1980s, China has incorporated modern biotechnology into its science and technology development plan, and the research in the past 20 years has achieved fruitful results. At present, five transgenic crops, including insect-resistant cotton, have been approved for commercial production. The planting area of insect-resistant cotton with Bt insecticidal protein gene 1998 is1.20 thousand hectares. According to the data, by the first half of 2000, 48 kinds of transgenic crops and 49 kinds of transgenic crops had entered the pilot test and environmental release test respectively. In recent years, China has made many achievements in the research and development of modern biotechnology. However, compared with developed countries such as Europe and America, the overall level of modern biotechnology development in China is still low. As long as we treat it correctly, develop it rationally and manage it effectively, we may be at the forefront of the world. It is predicted that genetically modified food is a new technological product. Although there are still some problems, it will be more and more perfect with the development of science and technology. We believe that as long as certain norms are followed, the development of biotechnology in China will be healthy and orderly, and our life will become more colorful because of genetically modified food brought by biotechnology. Predicting the future with good wishes, we no longer have to worry about the harm of pesticides. The food we eat is fresh, and our food will not be short ... Maybe diabetics can supplement insulin by drinking a special glass of milk every day. Maybe we will see all kinds of fruits sold in pharmacies, such as calcium supplement, iron supplement, cold treatment and antivirus ... It is very likely that genetically modified foods will make our tomorrow brilliant.