What Is a Transgene?

Genetically modified food refers to genetically modified biological strains obtained by using genetically modified biotechnology (transgenic biotechnology refers to a new breeding technology that introduces foreign genes into the genome of a specific biological species and makes it effectively express the corresponding product ^[1] ). Genetically modified organisms are foods that are produced directly or processed from raw materials. ^[2]

According to the source of genetically modified food, it can be divided into plant-based genetically modified food, animal-based genetically modified food and microbially-modified genetically modified food. ^{[3] At} present, genetically modified foods are mainly plant-based genetically modified foods. According to data released by the International Agricultural Biotechnology Application Service Organization (ISAAA), the global planting area of genetically modified crops was 179.7 million hectares in 2015, and commercial crop varieties are becoming more and more abundant . ^[2]

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Worried about genetically modified food? Because you don't understand. . . . . . 2017-12-14 13:12

November 19, 2015 is a day to be remembered in the history of biotechnology development. On this day, the United States Food and Drug Administration (FDA) approved the "transgenic salmon" program for human consumption, and the transgenic salmon became the world's first GM animal for food. ... more

GMO food classification criteria

As of 2013, there is no clear classification of genetically modified foods, and different classifications can be made according to different standards according to conventions. ^[4]

According to whether genetically modified food contains genetically modified food as a standard, it can be divided into the following three different types:

(1) The food itself does not contain genetically modified food, which means that although the food is derived from genetically modified organisms, the product itself will not have any transferred genes.

(2) Genetically modified foods do contain genetically modified ingredients, but their characteristics have changed during processing, and the transferred active genes no longer exist in genetically modified foods.

(3) Genetically modified foods do contain active genetic components. After people eat this genetically modified organism or food, the transferred genes and the genes inherent in the organisms will be digested and absorbed by the human body. ^[4]

According to the source of genetically modified food, it can be divided into the following three different types:

(1) Plant-based genetically modified food. The so-called plant-based genetically modified food,

Application of GMOs It refers to genetically modified foods that use genetically modified plants as raw materials.

(2) Animal genetically modified food. The so-called animal genetically modified food refers to genetically modified food that uses genetically modified animals as raw materials.

Genetically modified foods for animals are mainly cultured using embryo transfer technology to cultivate animals or animal products with fast growth rate, strong disease resistance and good meat quality.

(3) Microbial genetically modified food. The so-called microbial genetically modified food refers to a genetically modified food that contains a genetically modified microorganism as a raw material. Genetically modified microbial foods are mainly the use of microbial interactions to cultivate a series of new species that are beneficial to humans. ^[5]

According to the function of genetically modified food in food, it can be roughly divided into the following six types:

(1) Increased production of genetically modified foods;

Genetically modified domestic pig

(2) Genetically modified foods of controlled maturity;

(3) Health-care genetically modified food;

(4) processed genetically modified food;

(5) Highly nutritious genetically modified food;

(6) New varieties of genetically modified foods. ^[6]

Genetically modified food properties

Advantages of genetically modified food

Genetically modified food has many advantages: it can increase crop yield, reduce production costs, enhance crop resistance to insects and viruses, improve the storage stability of agricultural products, shorten the time for crop development, get rid of the supply of four seasons, break the boundaries of species, and continuously cultivate New species produce foods that are good for human health. ^[7]

GM food disadvantages

There are also disadvantages to genetically modified foods: the so-called increase in output is obtained without being affected by the environment. If it encounters natural disasters such as rain and snow, it may also reduce production even more. At the same time, during the cultivation process, genetically modified crops may evolve into farmland weeds; other species may be affected by genetic drift; genetically modified foods may cause allergies. ^[7]

Development and category introduction of genetically modified food

According to a report issued by the International Agricultural Biotechnology Application Service Organization (ISAAA) on February 13, 2014, the global planting area of genetically modified crops has increased more than 100 times in the 18 years of commercialization of genetically modified crops, an increase from 1.7 million hectares in 1996. By 2013 175 million hectares. Among them, the United States is still the world's leading producer of genetically modified crops, with a planting area of 70.1 million hectares. It accounts for 40% of the global planted area. More than 18 million farmers in 27 countries worldwide planted GM crops in 2013. The planted area increased by 3% compared to 2012, which is an increase of 5 million hectares. In 2013, the top five countries in planting genetically modified crops had planted areas of more than 10 million hectares, respectively in the United States, Brazil, Argentina, India, and Canada. The area of genetically modified crops in developing countries has exceeded that of developed countries for two consecutive years. It accounts for 54% (94 million hectares) of the global planting area of genetically modified crops. ^[8]

Genetically modified food

Plant genetically modified foods are an important source of genetically modified foods, and there are mainly three types of genetically modified plants that make up such foods. The first category is herbicide-resistant transgenic plants, such as 5-enolacetone shikimate-3-phosphate synthase (EPSPS) gene herbicide-resistant soybeans, this soybean and related foods made from this soybean (such as soybean oil ) Also belongs to genetically modified food; the second category is insect-resistant transgenic plants, such as Bt-resistant insect-resistant corn; the third category is genetically modified plants that improve product quality, such as rice that changes the composition and content of starch, disease-resistant sweet peppers, Tomatoes that are kept fresh for a long time. At present, China has approved the commercial production of six kinds of transgenic plants such as antiviral papaya and storage-resistant tomato. ^[9]

Genetically modified food

Transgenic animals are mainly used in medical treatment, construction of disease models, organ transplants, etc., while transgenic animals used for food are mainly auxin gene animals. It is difficult to obtain safety approval for edible genetically modified animals, partly because of auxin problems, and partly because of potential ecological risks. If transgenic animals escape to the wild, competing for food and mating with wild animals will not only contaminate the gene pool of the species, but may also lead to the extinction of non-transgenic wild animal groups. In 2015, a fast-growing salmon became the world's first genetically modified animal approved for human consumption in the United States. Salmon is the main ingredient of western and Japanese cuisine. Not only is it delicious, but it is also rich in cardiovascular health omega-3 fatty acids. The US company that developed the genetically modified fish filed a marketing application with the Food and Drug Administration (FDA) in 1995 and did not meet all FDA requirements until 2009. In 2010, the FDA granted its safety certificate. Normal salmon takes 30 months to mature, and genetically modified salmon can be served on the table in 16 to 18 months. These fish are all sterile female triploids, thus avoiding the problem of transgenic salmon contaminating wild fish genes. Following genetically modified salmon, genetically modified animal foods such as "environmental pigs" developed by Canada to efficiently use phosphorus to reduce environmental pollution, and "super muscle pigs" developed by Chinese and Korean scientists are expected to enter the market in the near future. ^[9]

Genetically modified foods

Microbial genetically modified food does not refer to genetically modified microorganisms, but foods made with genetically modified microorganisms, typically cheese. Cheese is a common food. Two processes, fermentation and curd, are used in the production process. The rennet that acts as a curd is derived from the folds of the stomach of a weaned calf. Conventional methods require the rennet to be extracted from the stomach to produce cheese after the calf is slaughtered. Now the use of transgenic microorganisms has been able to produce large amounts of rennet in vitro, avoiding the innocent death of calves, and reducing production costs. More than two-thirds of cheese in the United States uses this genetically engineered rennet in its production. Except for common cheese, bread, beer, and alcoholic beverages processed by this type of genetically modified microorganisms are all microbial genetically modified foods. ^[9]

Genetically modified foods

Whether it is plant-based genetically modified food, animal-based genetically modified food, or microbial-based genetically modified food, we must eat it as a food that fills our stomachs, and in the end, this type of genetically modified foods can also fill our stomachs, but it is the most important Yes, this kind of food can also prevent diseases. This kind of food is "vaccine food". At present, more and more disease resistance genes are being transferred into plants, enabling people to achieve the purpose of disease prevention while tasting the deliciousness of fresh fruits. For example, our country is developing tomatoes that can prevent hepatitis B. In addition to "vaccine food", we use genetically modified animals and plants as bioreactors to produce medicinal proteins that belong to this special type of genetically modified food. At present, we can use animal reactors to produce pharmaceutical proteins such as human hemoglobin, trypsin inhibitor, and human milk protein, which have also played a huge role in the treatment of diseases. ^[9]

Safety Evaluation of Genetically Modified Food

Origin of GM food safety issues

In the 1960s, PaulBerg spliced the simian virus SV40 and the blunt ends of E. coli DNA fragments. Created the world's first recombinant DNA. At the Cold Spring Harbor Conference in 1971, RobeaPollack proposed that SV40 is a tumor virus that is released into nature and may become a potential carcinogen, so the trial was terminated. This conference is the first to discuss the safety of recombinant DNA. The following year, the European Molecular Laboratory (EMBO) specifically discussed the potential harms of genetic recombination technology. At the Gordon conference in the United States on June 13, 1973, the safety of genetically modified crops was discussed, and some related suggestions were made. ^[8]

Historic milestones in genetically modified food

Domestic opposition to GM rice banners In February 1975, the Asilomar conference was held in California, USA, specifically to discuss the safety of genetically modified organisms. This conference was the first formal conference on genetic engineering technology, that is, the safety of genetically modified organisms. It became a "historical milestone of human society's concern for the safety of genetically modified organisms." After the Asilomar meeting, the National Institutes of Health (NIH) released the "Recombinant DNA Molecular Research Guidelines", the Organization for Economic Cooperation and Development (OECD) issued the "Biotechnology Management Regulations", Europe and the United States and Japan also issued some relevant guidance documents . in 1989. With the first commercial production of bovine chymosin, a genetically modified and transgenic food, the safety of genetically modified organisms has received more and more attention. The World Health Organization and the World Health Organization (FAO / WHO) held the first expert consultation meeting on the safety of genetically modified foods in 1990, which took a first step in safety evaluation. The meeting reviewed the status of biotechnology in food production and processing for the first time, and discussed the general and specific issues of food safety evaluation of biotechnology. It was considered that traditional toxicological methods of food safety evaluation were no longer applicable to genetically modified foods: and In 1991, a report on "Biotech Food Safety Analysis Strategies" was published. ^[8]

Basic principles of genetically modified food

1993. The OECD specifically held a meeting on the safety of genetically modified foods and conducted a report on "Safety Evaluation of Modern Biotechnology Foods: Concepts and Principles". "Principle of Substantial Equivalence". It refers to the analysis of the agronomic traits of genetically modified crops and the types and quantities of major nutrients, nutritional antagonists, toxic substances and allergic substances in food, and compared with corresponding traditional foods. If there are obvious differences, it is considered that the genetically modified food and the traditional food are substantially equivalent in terms of eating safety, and there is no safety problem. In 1995, WHO formally applied the "substantial equivalence principle" to the safety evaluation of modern biotechnology plant foods, the FAO / WHO Expert Consultation Meetings in 1996 and 2000, and the World Codex Committee in Japan in 2000 and 2001 ( The meeting of the Intergovernmental Task Force on Genetically Modified Foods (CAC) also affirmed the "substantial equivalence principle". So far, the basic principles of safety and health evaluation of genetically modified food have been recognized worldwide.

The conference divided the substantive equivalence into the following three categories:

(1) Equivalent to traditional foods and food ingredients;

(2) Except for certain specific differences, it is equivalent to traditional foods and food ingredients;

(3) There is no substantial equality with traditional foods and food ingredients. ^[8]

Basic content of genetically modified food

The safety evaluation of genetically modified food is inseparable from the safety of genetically modified food. The main content of China's safety assessment of genetically modified foods includes analysis of key components and nutritional evaluation of genetically modified crops and their products, toxicological evaluation of genetically modified crops and products, allergenicity evaluation of gene sources and foreign gene expression products, and intestinal microorganism Health evaluation, etc. Simply put, genetically modified foods must be evaluated for nutrition, toxicology, and allergenicity before they are approved for commercial production. ^[8]

(1) Nutrition evaluation

Genetically modified foods are all produced by exogenous gene expression to produce new varieties similar in appearance to gene receptors. Basic analysis of the nutritional composition and chemical properties of traditional foods and genetically modified foods should be the first research task. Nutrition evaluation mainly targets substances closely related to human health nutrition such as protein, starch, cellulose, fat, amino acids, fatty acids, carbohydrates, vitamins, mineral elements, and anti-nutritional factors (phytic acid, protease inhibitors, tannins, etc. ), If there is a statistical difference compared to traditional food, you should also fully consider whether this difference is within the reference range of this type of food. In addition, nutritional evaluation can be carried out by observing the feed intake and digestibility of genetically modified foods. ^[8]

(2) Toxicological evaluation

Toxicological evaluation mainly includes the evaluation of foreign gene expression products and toxicological testing of whole foods. The evaluation of foreign gene expression products is mainly through bioinformatics analysis. The amino acid sequences of known toxic proteins were compared to see their homology, followed by tests to simulate gastrointestinal digestion and thermostability, and rodent tests for acute toxicity. According to the situation of the expression product produced by the foreign gene, it can be used for acute toxicity, hereditary toxicity (triple test: sperm abnormality test, bone marrow micronucleus test, Ames test), subchronic toxicity, chronic toxicity, immunotoxicity, etc. experimenting. The toxicological evaluation of whole foods mainly uses 90-day animal feeding tests to investigate the long-term effects of genetically modified foods on human health. The animals currently used are generally rats, mice, pigs, sheep, chickens, monkeys, etc. For animal prices, rats are usually selected for 90-day subchronic toxicity tests. Generally speaking, if there is no special abnormal response in the subchronic toxicity test of genetically modified food, it is considered that such food will not cause adverse effects on human health during long-term use. ^[8]

(3) Evaluation of allergenicity

In 1988, the International Food Biotechnology Commission established standards and procedures for the evaluation of the safety of genetically modified foods, including allergenicity. At present, the internationally recognized allergy evaluation strategy for foreign gene expression products in genetically modified foods is the allergy evaluation procedure and method issued by FAO / WHO in 2001. The main reason for the allergy evaluation of genetically modified food is that the genetically modified food contains a specific protein expressed by a foreign gene, whether the protein encoded by the foreign gene is a known allergen or it has the amino acid sequence of a known known allergenic protein. Obvious homology or allergenic proteins in the protein family to which they belong may cause allergic reactions in genetically modified foods. The main methods for sensitization evaluation include comparison of amino acid sequence homology with known allergens, serum screening test, simulated gastrointestinal digestion test and animal model test. Finally, the potential sensitization of the protein produced by the foreign gene is comprehensively determined. The content and method of evaluation vary according to the donor of the foreign gene. ^[8]

(4) Other evaluations

The safety evaluation of genetically modified foods also includes research on undesired effects, horizontal transfer of foreign genes and intestinal flora. These are still in the scientific research stage and have not been included in the safety evaluation indicators of genetically modified foods. The development of these scientific research will reveal the impact of genetically modified technology on the organism itself and human and animal health, and provide more comprehensive scientific data for the development of genetically modified technology. ^[8]

Genetically Modified Food Evaluation Program

Substantial equivalence is the guiding principle before the implementation of the safety evaluation process. The main points of a comprehensive food safety evaluation are:

(1) Safe consumption history, ingredients, nutrition, toxic substances, anti-nutrients, etc. of the parent (host) crop.

(2) The history of safe use of donor genes, the molecular characteristics of gene combinations and the nature and marker genes inserted into the host genome, taking into account horizontal gene transfer and DNA safety.

(3) Evaluation data on the hazards of gene products, including toxicology and allergies.

Through an in-depth evaluation of the safety of the "starting materials" and a comprehensive evaluation of the transformation process, in order to ensure that new crops are "as safe" as their traditional counterparts, the phenotype and agronomy of genetically modified crops must also be based on the principle of substantial equality The comprehensive evaluation of the equivalence of academic traits, composition, comprehensiveness, nutrition and feeding, etc., proved that they are equivalent to traditional counterparts. Countries used this method to evaluate more than 50 GM crops, and concluded that the food and feed produced by GM crops are as safe and nutritious as those produced by traditional crops. ^[10]

GMO food regulations and policies

Different countries have adopted different policies when protecting intellectual property rights for genetically modified biotechnology. The typical ones include the dual-track protection model represented by the United States and Japan and the single-system protection model represented by the European Union. For example, the United States mainly implements a dual-track protection model for genetically modified intellectual property rights through patent laws and specialized laws: Among them, the patent law covers any genetically modified technology and its products, and the specialized laws are targeted at a specific species. The applicant may choose to apply for a patent right or apply for a special law protection right according to the actual situation. However, Japan has adopted the latter-oriented compromise protection model-combining patent protection with plant variety rights. Similar to the United States, Japan does not stipulate non-patentable objects in its patent law like China s patent law or the European Patent Convention (EPC), but only defines the invention in Article 2 of its Patent Law: "So-called inventions, It refers to the technical conception and high creation using the laws of nature. " Therefore, in Japan, whether it is genetically modified animals or plants or microorganisms, as long as they meet the essential conditions of the invention (practicability, novelty and creativity, which is commonly referred to as the "three natures"), patent protection can be obtained. Some developing countries, such as Brazil, have been at the forefront of research on genetically modified plants as the country that started planting genetically modified crops earlier in the world. In Brazil, the government and the general public attach great importance to the protection of genetic resources. In response to the rapid development of biotechnology, especially the use of genetically modified biotechnology for agricultural development and the expansion of production applications, Brazil has enacted the Biosafety Law and the GMO Trade Law, which prohibits unauthorized persons from accessing and using biological resources and traditions. Knowledge to intercept the outflow of biological resources. ^[11]

In October 2014, the Ministry of Agriculture sent a letter to the State Administration for Industry and Commerce, inviting requests to strengthen the management of genetically modified advertising. On October 9, an official from CCTV's advertising department said that the use of misleading advertisements such as "healthier and safer" for non-GMO advertising was banned. We will strengthen the review of advertisements for GM and non-GMO products. Among them, there is no commercial cultivation of GM varieties in China and the world, such as rice, peanuts and processed products. The use of non-GMO advertisements is prohibited. Commercialized products of soybeans, rapeseed, and other processed products of genetically modified varieties and their processed products are prohibited from using non-GMO words, such as healthier and safer misleading advertisements, in addition to receiving certification materials in accordance with regulations. ^[12]