Gene pollution: the trouble of the new century

Introduction: there are fish genes in tomatoes Since human beings mastered the skill of operating on biological genes, human beings have learned a kind of ability, which is called "arbitrary tampering with God's works" by some people These "works" are not only sealed in test tubes in the laboratory, they have already spread on tens of millions of hectares of land These new crops are called "genetically engineered agricultural crops" Indeed, all of our traditional cultivated crops and domestic animals are quite different from the original biological species and have been genetically modified In this sense, genetic modification is nothing new Since the day when human ancestors mastered agricultural production technology thousands of years ago, they have been constantly carrying out great practice of gene transformation of crops, livestock and poultry, but this does not constitute a reason to say that there is no essential difference between genetically engineered agricultural organisms and traditional agricultural organisms The gene exchange of traditional agricultural organisms through chromosome recombination is basically carried out according to the law permitted by the organisms themselves, while gene engineering crops or animals "transplant" genes related to certain specific characters designed and assembled artificially, so that they can obtain the expected new characters in a relatively short time For genetically engineered organisms, one thing is very special, that is, the genes "transplanted" to them can come from any organism, completely breaking the original barrier of the species, "transplantation" is "mandatory", which is rarely possible or impossible in the natural state! In the natural state, tomato will never have the gene of fish, and corn will never have the gene of firefly From the perspective of biosafety, genetically engineered organisms and traditional hybrid organisms can not be equated, but the "substantial equivalence" evaluation principle of genetically engineered food proposed in the past is not comprehensive What was unimaginable 20 years ago 20 years ago, people would never have imagined that there are such a large number of recombinant organisms entering the nature At the time of the rise of genetic engineering technology in the 1970s, the experiment of gene recombination must be carried out in the "negative pressure" laboratory Various levels of physical barriers and biological barriers have been set up here to prevent genetically modified organisms (mainly microorganisms at that time) from entering the human body or escaping to the outside world Although the regulation of non pathogen genetic engineering experiment has been relaxed in the future, the principle of biosafety remains unchanged For gene recombination experiments, governments still issue corresponding operating procedures to prevent recombinant organisms from entering the human body or spreading outside the laboratory It is undeniable that although the safety of these dozens of genetically engineered crops to human body and environment has been seriously considered in the approval, it has been proved that the past consideration is not sufficient, there are limitations in understanding and lack of long-term data In just a few years, genetically engineered crops have been popularized so rapidly in North America One of the important reasons is that in order to compete for the market, bioengineering companies release genetically modified crops to the field too early to fully consider and conduct research on the long-term impact on human body, especially on the environment A far-reaching new concept of environmental protection in the United States, it is an indisputable fact that genetically modified pollution is caused by the large-scale promotion of genetically engineered crops From planting to finished products, pollution may occur in almost every link Hybridization in the field is the original pollution, and the second pollution occurs in the uncleaned warehouse and transportation links, resulting in the seeds of traditional crops mixed with the seeds of genetic engineering crops The pollution has reached such a level that the most picky food importers in the European Union and Japan have no choice but to stipulate that the seeds of traditional crops imported from North America, of which no more than 0.1% of genetically modified pollution is qualified They seem to have no hope of getting absolutely pure traditional crop seeds Little is known about the consequences It has become a fact that transgenes in genetically engineered crops can spread to other crops of the same kind through the sexual reproduction process carried out by pollen (wind blown or insect borne) This is a process called "gene drift" in genetics The gene of this artificial combination spreads to other cultivated crops or natural wild species through transgenic crops or domestic animals, and becomes a part of the latter gene, which is called "gene pollution" in environmental biology This is a far-reaching new concept of environmental protection The safety of genetically engineered crops and animals can be evaluated from two aspects: the safety of human body and the safety of environment There are still great disputes on these two aspects This paper only deals with the possible ecological risk of release of genetically engineered crops to nature Transgenes in genetically engineered crops can spread to traditional crops, and their harm is reflected in the impact on the formed agricultural ecosystem Although it is difficult to predict the consequences of gene pollution on traditional crops, it is undoubtedly harmful Traditional crops include a large number of varieties On their chromosomes, there are all kinds of genes for human needs, which are preserved by human cultivation and selection for thousands of years It is a huge resource There is no dispute that the genes of natural species can not be polluted The dispute is whether this kind of pollution will occur In theory, gene drift is possible between almost all crops because of the existence of wild species and related species with sexual reproductive compatibility (copulability) in their distribution areas In fact, in recent years, it has been reported that the herbicide resistant genes of genetically engineered maize have drifted to the wild maize like plants in the vicinity, and the herbicide resistant genes of genetically engineered rape have drifted to the wild turnips in the vicinity Some resistant genes have been polluted by wild plants, which have resulted in the emergence of so-called "super weeds" Some genetically engineered organisms are particularly dangerous, such as transgenic fish and some transgenic invertebrates, as well as transgenic forests and transgenic algae, which have strong fecundity or release a large number of reproductive gametes to the outside world In the study of the model system, American scholars have proved that the transgenic of genetically engineered fish can spread to the same species in the wild So in foreign countries, genetically engineered fish can only be cultured in an absolutely closed greenhouse As a result, some wild species may obtain new characters from transgenes, such as cold tolerance, disease resistance or fast growth, so they may have stronger vitality; or as another view holds, their vitality is weaker, because they have not gone through the process of natural selection No matter which result, it will break the ecological balance of nature! Genetically engineered Bt insecticidal crops continuously and uncontrollably produce large doses of Bt toxin protein, which can destroy pests on a large scale, but the insecticidal process can not be controlled, which may cause a sharp decline in the number of natural enemies (such as insects and birds) living on these pests, threatening the ecological balance A study in Scotland found that a aphid sucks the juice of Bt toxin from genetically engineered crops, and then it is preyed on by a beneficial insect, beetle Bt toxin protein is transferred to beetle and affects its reproduction A study from Canada reported that genetically engineered Bt crops can also poison another natural enemy of pests, membranous wing insects In the United States, scientists have found that genetically engineered Bt corn pollen can poison a non-target insect, the American monarch butterfly, which is regarded as the most beautiful butterfly in the world by Americans, and has attracted public attention The new concept of modern agricultural ecosystem is not to eliminate pests, but to reduce them to the level of no disaster For example, the transfer of Bt toxin protein through food chain is a serious interference to the maintenance of agricultural ecosystem balance and the implementation of traditional biological control It has also been found that Bt toxin protein produced by genetically engineered Bt insecticidal crops can leak from the roots of crops to the soil or enter the soil with the leaves of crops, and its toxicity can be retained for at least 7 months It is harmful to invertebrates in soil and water, but not in traditional BT powder The carrier DNA used in animal and plant transgenes contains a special gene for marking - antibiotic resistance gene The risk of this gene has not been fully recognized Researchers in Finland have found that antibiotic resistance genes in genetically engineered foods can be transferred to bacteria in the human gut Although no one has reported that the food can make intestinal bacteria, especially pathogenic bacteria, resistant to antibiotics in human body, the risk cannot be excluded because the gene itself has a movable nature On the other hand, no one has been able to prove that the resistance genes in genetically engineered food will never be transferred to human intestinal microorganisms What is the obligation of consumers to bear this risk? Ethical and responsible scientists should refuse to use antibiotic resistant genes when making transgenic animals and plants for genetically engineered crops Unfortunately, some people still use it Now some governments have made it clear that the production and sale of genetically engineered foods containing any antibiotic resistant genes are prohibited There are also some genetic pollution in nature that may not be imagined at all For example, scientists in Germany have found that genetically engineered rape has polluted the microbes in the intestines of honeybees The significance of the discovery is to remind people that genetic pollution will probably be pervasive Gene is the basic component of all life, and reproduction is the basic feature of life The essence of biological reproduction is gene replication Gene pollution is the incorporation of artificially recombined genes into natural biological species These foreign genes can be proliferated with the reproduction of the polluted organisms, and then spread with the spread of the polluted organisms Therefore, gene pollution is the only kind of pollution that can be continuously proliferated and diffused, and can not be eliminated This is a very special and dangerous environmental pollution Can we keep the last "pure land"? It is estimated that there are more than 10 million species of living things that have been found and have not been found on the earth, and their unique genes are formed during the evolution of life on the earth for 3 billion years The natural biological gene bank is a huge treasure for human beings, an immeasurable wealth, and it also maintains the fate of human beings But the worrying thing is: can we still hold the natural biological gene pool, the last "pure land" on the earth? We must face the fact that the genetically engineered crops that have been widely popularized are not ideal and must be improved Since we can do better, why rush for success now? If you are eager for success, you may