BIOTECHNOLOGY - Inshyna N.M. - 2009

CHAPTER 1. GENETIC ENGINEERING

Advantages and Disadvantages of Using Transgenic Plants and Animals in Agriculture

Applying the Achievements of Genetic engineering in agriculture is a primary objective of agricultural biotechnology. The most advanced branch of agricultural biotechnology is the application of Cell biology, which involves The Use of PLANT AND ANIMAL cell, tissue, and organ cultures. In practice, these Methods enable solutions to problems such as the rapid propagation of valuable plant genotypes, their eradication of pathogenic Viruses, the generation of somatic hybrids, Artificial Insemination in animals, embryo transfer, and The production of Monoclonal Antibodies AND BIOLOGICALLY ACTIVE SUBSTANCES.

Another vital area of modern biotechnology application is the use of molecular genetic markers in breeding, as well as for propagating plants and animals and preserving their Gene pools. Markers are utilized to identify and map valuable genes or trait loci on Chromosomes, construct chromosome maps, control seed quality, and compile molecular genetic catalogs of cultivars and lines.

Obtaining Transgenic Plants makes it possible to develop a new generation of varieties resistant to aggressive pathogens and pests, viruses, Viroids, Mycoplasmas, abiotic stresses (low and high temperatures, soil salinization or acidification, drought, waterlogging), and herbicides. The use of biological plant protection products, plant and animal growth stimulators, and microbial fertilizers helps reduce the amounts of chemical plant protection agents and mineral fertilizers, improve product quality, and establish eco-friendly technologies. Genetically engineered Vaccines, sera, and monoclonal antibodies are employed for the Prevention, Diagnosis, and Treatment of major agricultural animal diseases.

The advantages and disadvantages of applying biotechnology in agro-industrial production are summarized in Table 1.6.

Class="center">Table 1.6.

Advantages and Disadvantages of Applying Biotechnology in Agriculture

The ability to transfer genes across different taxonomic groups is a distinct advantage of the biotechnological approach in breeding. Traditional breeding methods require significant time and effort, whereas Genetic Engineering techniques accelerate The Development of novel plants with unique traits.

Biotechnology allows new crop varieties to be bred within 2 to 3 years, compared to 10 years or more for traditional breeding. However, the success of the biotechnological approach depends on a precise understanding of the molecular mechanisms underlying the trait. For instance, transferring cold tolerance into a crop plant typically involves a wild donor species characterized by low yield and other undesirable agronomic traits, a process that could take decades through conventional breeding. Cloning the genes responsible for freezing tolerance and introducing them into the target plant occurs without transferring the undesirable traits of the donor. Bacteria or animal Cells can serve as sources of cold-tolerance genes. Products of plant biotechnology are significantly less aggressive than their progenitor or wild-type plants. Experiments conducted in the United Kingdom demonstrated that genetically modified plants possess no survival advantages in natural environments compared to their wild relatives. This confirms the low probability of herbicide- and insect-resistant GM plants surviving in the wild or turning into superweeds.

The fiercest debates revolve around the use of genetically modified organisms (GMOs) in agro-industrial production.

The most widespread genetically modified crops are soybean, corn, rapeseed, and cotton. The vast majority of transgenic crops are cultivated in the USA, Canada, and Argentina, whereas Austria, France, Greece, and the UK have imposed moratoria on the import of GM foods.

Since 2003, European Union countries have mandated labeling to inform consumers about the presence of GM products. According to European standards, the maximum allowable content of GM organisms in food products is 0.9%. Approximately two-thirds of US food products contain GM ingredients. Accurate and reliable information regarding the safety of biotechnological products must be accessible to the general public. In accordance with WHO recommendations, the potential toxicity, carcinogenicity, and allergenic properties of genetically modified organisms are actively evaluated.

An objective assessment of potential negative impacts of genetically modified organisms on human health and the environment is essential. Special attention must be paid to the fact that the agricultural sphere is an anthropogenic system with suppressed natural defense mechanisms, which requires extreme caution when evaluating the consequences of introducing new organisms into it.

Currently, genetic engineering remains technically imperfect, as it cannot precisely control the gene insertion process. DNA knowledge is incomplete, with the Functions of only 3% of DNA having been studied. It is impossible to predict the exact insertion site and the resulting effects of a new gene, and determining the long-term consequences of genetic manipulation remains difficult.

In 1998, British scientist Árpád Pusztai announced for the first time, based on experimental data, that feeding genetically modified potatoes to laboratory rats caused severe damage to their Internal Organs and immune systems. The animals experienced significant alterations in the digestive tract, Liver, Thyroid Gland, and Spleen, along with a decrease in Brain volume. This announcement triggered mixed reactions. The institute where Dr. Pusztai worked claimed his research findings were biased; however, an independent commission of 20 international scientists confirmed the validity of his Conclusions. Consequently, the safety of genetically modified foods requires a substantial reassessment.

In May 1999, John Losey reported that pollen from genetically modified corn containing a low concentration of pesticide could kill monarch butterfly larvae. In November 1999, a special scientific conference was held to discuss the findings of A. Pusztai and J. Losey, though no consensus was reached. Some scientists argued that Laboratory studies cannot accurately replicate natural environmental conditions. The persistence of such controversies indicates that breeding genetically modified plants and animals poses risks driven by the unpredictability of their development and behavior in nature.

Ecological, medical, and socio-economic risks (negative impacts) associated with the use of transgenic plants and animals are distinguished.

Ecological risks

- The emergence of super-pests resistant to natural toxins (a pest resistant to Bt-toxin has already been discovered in cotton fields).

- Disruption of the ecological balance (it has been proven that GM tobacco or technical rice used for manufacturing plastics and Pharmaceuticals are lethal to field-dwelling rodents).

- Loss of control over transgenes, leading to the appearance of superweeds resistant to pesticides, herbicides, and pests.

Cases of herbicide-resistance gene transfer from genetically modified rapeseed to wild mustard have been documented. The risk of gene flow from transgenic crops to wild species or weeds can be mitigated by adhering to proper agricultural practices.

Medical Risks

- Increased allergy risks associated with genetically modified foods. As a rule, testing GM products on allergic individuals is not included in the safety assessment protocols for new foods.

- Potential toxicity and threats to human health. Reliable methods for verifying the safety of genetic engineering products do not currently exist. In 1989, the Japanese chemical company Showa Denko introduced a new GM variant of the dietary Supplement L-Tryptophan to the US market. As a result, 37 people died and over 5,000 were disabled with a potentially fatal condition known as eosinophilia-myalgia syndrome, an incurable Blood disorder. It is known that the Toxic effects of a protein may take more than 30 years to manifest, yet safety trials for GM products typically last only three years.

- Antibiotic Resistance. To determine whether a target gene has successfully integrated into the DNA chain, geneticists tag it with an antibiotic resistance marker gene. However, removing this marker gene is impossible. Consequently, the consumption of GM products can neutralize the effectiveness of prescription Antibiotics.

- Potential emergence of new dangerous viruses. Viral genes integrated into a genome can recombine with The genes of infectious viruses. These novel viruses may exhibit higher virulence and lower host Specificity (for instance, plant viruses could potentially become harmful to insects, animals, or humans).

Socio-Economic Risks

The majority of social and economic threats posed by genetic engineering relate to food security. Studies on the economic impact of gene technology, specifically regarding the yield levels of transgenic crops, yield mixed results. In some instances, the productivity of GM crops was significantly lower than that of traditional varieties. Scientists have concluded that the efficacy of these new crops depends on a multitude of factors, including weed and insect pest pressures, weather conditions, soil types, and others.

Transgenic plants are often sterile and do not produce viable seeds, requiring farmers to purchase new GM seeds from biotechnology companies year after year. If transgenic crops become widespread, as few as 10 companies could control 85% of the global agrochemical market, severely limiting consumer freedom of choice in food purchasing.