Genetic modernization
Dispel the myths about GMOs
Alexander Panchin, Researcher at the Molecular Evolution Sector of the Institute of Information Transmission Problems of the Russian Academy of Sciences
"Popular Mechanics" No. 8, 2014
Published on the website "Elements"
In the universe of the strategic computer game StarCraft, the extraterrestrial race of Zerg is notable for having learned to assimilate the genetic material of other organisms and transform their own genes, changing and adapting to new conditions. This, at first glance, fantastic idea is much closer to the real possibilities of living organisms than it seems.
Today we know a lot about DNA: more than two million scientific publications have been devoted to this double-stranded molecule. A DNA molecule can be considered as a text written using an alphabet of four letters (nucleotides). The totality of all the nucleotides that make up the chromosomes of any organism is called the genome. The human genome has approximately three billion "letters".
Individual sections of the genome are isolated genes – functional elements that are most often responsible for the synthesis of specific proteins. Humans have about 20,000 protein-coding genes. Proteins, like DNA molecules, are polymers, but they do not consist of nucleotides, but of amino acids. The "alphabet" of amino acids that make up proteins has 20 molecules. Knowing the nucleotide sequence of a gene, it is possible to accurately determine the amino acid sequence of the protein that it encodes. The fact is that all organisms use the same (with slight variations) well–studied genetic code - the rules for matching codons (triples of nucleotides) to certain amino acids. This versatility allows genes from one organism to work in another organism and at the same time produce the same protein.
Natural EngineeringOne of the main methods of genetic engineering of plants uses agrobacteria and the mechanism of modification of plant genomes developed by them.
The genes of agrobacteria living in the soil encode special proteins that can "drag" a certain DNA molecule into a plant cell, embed it into the plant genome and thereby force the plant to produce the nutrients necessary for the bacteria. Scientists borrowed this idea and found its application by replacing the genes needed by bacteria with those that encode proteins needed in agriculture. For example, Bt toxins produced by the soil bacteria Bacillus thuringiensis, which are absolutely safe for mammals and poisonous for some insects, or proteins that give a plant resistance to a specific herbicide.
Gene exchange for bacteria, even unrelated ones, is a very common phenomenon. It is because of this that microbes resistant to penicillin appeared within a few years after the start of its mass use, and today the problem of antibiotic resistance has become one of the most alarming in medicine.
From viruses to organismsNot only bacteria, but also viruses are engaged in natural "genetic engineering".
In the genomes of many organisms, including humans, there are transposons – former viruses that have long been embedded in the DNA of the host and, as a rule, without harming it, can "jump" from one place in the genome to another.
Retroviruses (such as HIV) are able to embed their genetic material directly into the genome of eukaryotic cells (for example, human cells). Adenoviruses do not embed their genetic information into the genomes of animals and plants: their genes can turn on and work without it. These and other viruses are actively used in gene therapy to treat a whole range of hereditary diseases.
Thus, natural genetic engineering is very widely used in nature and plays a huge role in the adaptation of organisms to the environment. More importantly, all living organisms are constantly undergoing genetic changes as a result of random mutations. An important conclusion follows from this: in fact, every organism (except for clones) is unique and genetically modified compared to its ancestors. He has both new mutations and new combinations of previously existing gene variants – dozens of genetic variants are found in the genome of any child that none of the parents had. In addition to the emergence of new mutations, during sexual reproduction, a new combination of genetic variants already existing in the parents occurs in each generation.
Tested in experimentsThe safety of food products containing genetically modified organisms (GMOs) is being actively discussed today.
For the products of genetic engineering carried out by man, the term "genetically modernized organisms" is much better suited, since genetic engineering allows you to accelerate those processes of genetic changes that occur independently in nature and direct them in the right direction for a person. However, there are no significant differences between the mechanisms of genetic modernization and the natural processes of genetic modification, so it is quite reasonable to assume that the production of GM foods does not carry additional risks.
However, like any scientific hypothesis, the safety of GMOs needed experimental verification. Contrary to numerous statements by opponents of GMOs, this issue has been very, very carefully investigated for more than a dozen years. This year, the journal Critical reviews in biotechnology published a review of almost 1,800 scientific papers devoted to the study of the safety of GMOs over the past ten years. Only in three studies there were suspicions about the negative impact of three specific GM varieties, but these suspicions were not justified, and in two more cases the potential allergenicity of GM varieties was established. The only confirmed case concerned a Brazil nut gene embedded in a GM soybean variety. The standard test of the reaction of the blood serum of people suffering from allergies to the protein of a new GM variety in such cases showed the existence of danger, and the developers refused to promote the variety to the market.
In addition, it is worth mentioning separately the 2012 review published in the journal Food and Chemical Toxicology, which included 12 studies on the safety of GMO consumption in several (from two to five) generations of animals and 12 more studies on animals of long-term (from three months to two years) consumption of GMOs in food. The authors of the review concluded that there were no negative effects of GMOs (compared to unmodernized analogues).
Genetic modernization using a T-plasmid, in which the genes that cause the tumor and the synthesis of nutrients for the parasite are replaced with genes needed by the developers of a new variety. The control gene for antibiotic sensitivity allows you to weed out cells in which the target gene has not been introducedScandalous revelations
Curiosities arise around some works allegedly showing the harm of individual GM plant varieties.
A typical example that opponents of GMOs love to cite is the sensational publication of the French researcher Seralini in the journal Food and Chemical Toxicology, who claimed that GM corn causes cancer and an increase in rat mortality. In the scientific community, Seralini's work caused heated discussions, but not because the researcher received and published some unique data. The reason was that, from a scientific point of view, the work was done extremely carelessly and contained gross errors that were noticeable at first glance.
Nevertheless, the photographs of rats with large tumors presented by Seralini made a huge impression on the public. Despite the fact that his article could not withstand objective criticism and was withdrawn from the journal, it continues to be quoted by opponents of GMOs, who are clearly not interested in the scientific side of the issue, and photos of sick rats are still shown from screens.
The scientific level of discussion of the potential dangers of GMOs in the media and in society as a whole is striking naivety. On the shelves of stores you can find starch, salt and even "non-GMO" water. GMOs are constantly confused with preservatives, pesticides, synthetic fertilizers and food additives, to which genetic engineering is not directly related. Such discussions lead away from the real problems of food safety into the field of speculation and substitution of concepts.
Starch and fats without GMOsAccording to GOST R 51953-2002 "Starch and starch products", modified starches are called, the properties of which are changed (naturally, for the better compared to natural) as a result of physical, chemical, biochemical or combined processing.
Whether out of ignorance, or for a red word, ordinary people are often frightened by "genetically modified starch". Another common blunder of illiterate journalists is "transgenic fats". So often called trans isomers of fatty acids, or trans fats. Genetic methods have nothing to do with starch or trans fats.
The dangers are real and notHowever, neither this article nor other scientific papers try to prove that GMOs are "absolutely safe".
In fact, no food is absolutely safe, because even Paracelsus said the famous phrase: "Everything is poison, and nothing is devoid of poison; only one dose makes the poison invisible." Even ordinary potatoes can cause allergies, and green ones contain toxic alkaloids – solanins.
Can the work of existing plant genes somehow change as a result of embedding a new gene? Yes, it can, but no organism is immune from changes in the work of genes. Can a new plant variety appear as a result of genetic engineering, which will spread beyond agricultural land and somehow affect the ecosystem? Theoretically, this is possible, but it also happens everywhere in nature: new species appear, ecosystems change, some species die out, others take their place. However, there is no reason to believe that genetic engineering carries additional risks for the environment or for human or animal health. But these risks are constantly trumpeted in the media. Why?
The GMO market is largely monopolized. Among the giants, Monsanto is in the first place. Of course, large producers of GM seeds and technologies are interested in profit, they have their own interests and their own lobby. But they earn money not "out of thin air", but by offering mankind progressive agricultural technologies, for which producers vote in the most convincing way – in dollars, pesos, yuan, etc.
The main producers and suppliers of "organic" products grown using outdated technologies and, consequently, more expensive (but not of higher quality) are also not small farmers at all, but the same large companies with multibillion–dollar turnover. In the USA alone, the market for organic products amounted to $31 billion in 2012. This is a serious business, and since organic products do not have any advantages over GMOs, but are more expensive to produce, they cannot compete with GM varieties by market methods. So it is necessary to inspire unsubstantiated fear of the mythical "scorpion genes" through the media, which creates demand for expensive and non-technological "organic products". In addition, opponents of GMOs describing the terrible dangers of genetically modified varieties producing B.thuringiensis protein usually forget to mention that preparations based on such crops or proteins isolated from them are allowed (and widely used) in "organic farming". As well as natural manure, which can be a source of a bunch of pathogenic bacteria and other natural filth.
A bit of politicsToday, genetic engineering is one of the most studied technologies from the point of view of safety.
It allows you to create better food products, reduce the amount of pesticides used in the fields and protect the environment (yes, it is to protect: more insects and birds live in fields sown with Bt varieties than on "ordinary" ones, which have to be regularly treated with insecticides).
But there is another reason for the "fight" against GMOs – exclusively political. Countries that have lagged far behind in the field of biotechnology are trying to find a reason to prevent cheaper products from other countries from entering their market. However, such protection of domestic producers from foreign products makes sense only if it helps to gain time to develop their own technologies to a competitive state. If this is not done, there is a serious risk of falling behind the world scientific and technological level. Forever.
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