വികൃതി: ശാന്തി

വികൃതി: ശാന്തി

Health Risks And Other Possible Environmental Biohazards Due To The Application of Genetically Modified Organisms

Genetically Modified Organisms

A genetically modified organism (GMO) or genetically engineered organism (GEO) is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one molecule to create a new set of genes. This DNA is then transferred into an organism, giving it modified or novel genes. Transgenic organisms, a subset of GMOs, are organisms which have inserted DNA that originated in a different species. Some GMOs contain no DNA from other species and are therefore not transgenic but cisgenic. Genetic Engineering as a tool of Biotechnology necessary to utilize for the benefit of the nature and mankind. But now, the blind applications of the Bioengineering made the Biotechnology,in its naked essence as Thano-technology. Hybridizations does work harmoniously with superficial aspects of nature without fully disturbing the essential life force at the centre of each cell. Also with hybridizations, conscious life makes primary genetic decisions. We can understand this with an analogy. Fifty years ago few predicted that chemical pollution would cause so much environmental harm - with nearly 1/3rd of all species now threatened with extinction. Or that cancer rates would have doubled and quadrupled. No one has a crystal ball to see future consequences. Some of those releases, however, could wreak havoc with the planet's biospheres.

Possible Health risks:–

The Reports of health impacts of Genetically altered food started from 1989 in U.S., dozens of Americans died and several thousands were afflicted and impaired by a genetically altered version of the food supplement – L- tryptophan produced by Showa Denko, Japan’s third largest chemical company. (Mayeno and Gleich, 1994). Many other studies has been conducted in different part of the globe after this incident and confirmed that the GM foods are harmful to health, will lead to the serious health problems such as cancer and other degenerative diseases. In 1994, FDA approved Monsanto's rBGH, a genetically produced growth hormone, for injection into dairy cows – even though scientists warned the resulting increase of IGF-1, a potent chemical hormone, is linked to 400-500% higher risks of human breast, prostrate, and colon cancer. The hormone induces induces the malignant transformation of human breast epithelial cells." Rat studies confirmed the suspicion and showed internal organ damage with rBGH ingestion(Dr. Samuel Epstein,1989). Therefore it is significant to study more about the possible health risks of GM crops and GM foods. There are many perspectives to study about the possible health problems occur in human body.

The first step in estimating risk is identifying the potential harm. It is not very meaningful task: How much risk does rDNA pose? The concept of risk takes on meaning only when harm is identified. The question should be: What is the likelihood that rDNA will cause a specific disease such as in a single individual or in an entire population? The magnitude of the possible harm is incorporated in the question of risk, but differs in the two cases. The detention of rDNA refers specifically to the combination of DNA from two organisms outside the cell. If the DNA is combined within the living cells, the Guidelines do not pertain. Several methods that achieve the same goal–transferring genetic material from one cell to another, bypassing the normal sexual mechanisms of mating. Combining genes from different species may disturb an extremely intricate ecological interaction that is only dimly understood. Hence, such experiments, it is argued, are unpredictable and therefore hazardous. Citing some possibilities below,

1. Increased Food Allergies: Frequently foods we eat and crave are precisely those testing positive for food allergies. Cells in our body recognize this lack of vitality, producing antibodies and white cells in response. GM foods those we consume as part of our dietary source may lead to the allergic response and trigger the production of IgE antibodies inside the human body system as it is new to the immune system. A number of chance to occur autoimmune diseases enhanced by the foreign DNA fragments that are not fully digested in the human stomach and intestines. DNA fragments are absorbed into the bloodstream, potentially mixing with normal DNA. The genetic consequences are unpredictable and unexpected gene fragments have shown up in GM crops.

2. Possibility of Infectious diseases: There are much more possibilities to occur new infectious diseases. This occurs in multiple ways. There is growing resistance to antibiotics misused in bioengineering, the formation of new and unknown viral strains, and the lowering of immunity through diets of processed and altered foods. There is also the horizontal transfer of transgenic DNA among bacteria. Several studies have shown bacteria of the mouth, pharynx and intestines can take up the transgenic DNA in the feed of animals, which in turn can be passed on to humans. This threatens the hallmark accomplishment of the twentieth century - the reduction in infectious diseases that critically helped the doubling of life expectancy.

3. Horizontal Gene transfer: The main and most important impact of this GM crops are the responsibilities of Horizontal Gene transfer, the process in which an organism incorporates genetic material from another organism without being the offspring of that organism. This can happen, without warning, inside of our bodies creating an unpredictable chain reaction. A four-year study at the University of Jena in Germany conducted by Hans-Hinrich Kaatz revealed that bees ingesting pollen from transgenic rapeseed had bacteria in their gut with modified genes. Commonly found bacteria and microorganisms in the human gut help maintain a healthy intestinal flora. These, however, can be mutated. Mutations may be able to travel internally to other cells, tissue systems and organs throughout the human body.

4. Antibiotic Resistance: Much of genetic implantation uses a marker gene,commonly antibiotic or herbicide resistance gene to track where the gene goes into the cell. The resistant qualities of GM bacteria in food can be transferred to other bacteria in the environment and throughout the human body. This issue arose in connection with a GM-maize variety produced by Ciba-Geigy (now Novartis). The UK Advisory Committee for Novel Foods and Processes (ACNFP) recommended against authorization of this product for animal feed, its only projected use. This was because of the perceived risk associated with the transfer of an antibiotic-resistance marker gene in the maize to the bacterial gut of livestock that had been given the feed. If the antibiotic in question (ampicillin) was present in the animal feed, there was perceived to be an eventual possibility of transfer of the resistance gene to humans through transfer of resistant bacteria to those in contact with the cattle, although this has not been observed. The widespread use of antibiotics in animal feed, coupled with their widespread clinical use has already led to an alarmingly high level of antibiotic resistance in bacteria which infect humans.

Failure of RNA interference may also cause the integration of these viral marker gene with other microbes to produce harmful mutant varieties. The use of RNA interference for artificially manipulating gene expression was limited by the activation of cellular antiviral mechanisms. Exposure of cells to Si RNA sequences longer than 30 nucleotides interfere on gene expression, resulting nonspecific RNA degradation and reduced protein synthesis. Though this problem was circumvented a little by designing 19-29 nucleotides of Si RNA sequences, the complete chance of interference is yet cannot be tackled.

5. Superviruses: Viruses can mix with genes of other viruses and retroviruses such as HIV. This can give rise to more deadly viruses – and at rates higher than previously thought. One study showed that gene mixing occurred in viruses in just 8 weeks (Kleiner, 1997). This kind of scenario applies to the cauliflower mosaic virus CaMV, the most common virus used in genetic engineering which is a recombinogenic pararetrovirus - in Round Up ready soy of Monsanto, Bt-maise of Novaris, and GM cotton and canola. It is a kind of "pararetrovirus" or what multiplies by making DNA from RNA. It is somewhat similar to Hepatitis B and HIV viruses and can pose immense dangers.

6. Gene Silencing: We have, as yet, no control over where in the plant’s chromosomes a transgene will integrate. Some regions of the plant genome contain large domains of non-coding DNA, which will be highly methylated. Transgenes inserted into this part of the DNA are prone to become methylated themselves, and eventually to cease to function, although this may take several generations. Gene silencing is effectively non-reversible and the GM plant will revert to the way it was before it was modified.

7. GM DNA transfer in animals: Concerns have been expressed that the DNA introduced by genetic modification might be transferred across the wall of the gut to the host, and lead to genetic alteration of that host, despite the fact that we eat large amounts of degraded and undegraded DNA in our everyday diet. Experiments h ave shown that DNA consumed in the diet is very unlikely to survive intact beyond the stomach and into the gastrointestinal tract. That DNA which remains after digestion consists of very small fragments which do not contain whole genes. However, some experiments have shown that these fragments may enter the blood stream28 and that small amounts may even enter cells and attach to cellular DNA. Such DNA fragments would not function in the human or animal because of their small size. Furthermore, no evidence of active ingested genes, even those designed to work in human cells, has been found.

8. Birth defects and Shorter life span: As we ingest transgenic human or animal products there is no real telling of the impact on human evolution. We know that rBGH in cows causes a rapid increase in birth defects and shorter life spans.

Possible Environmental Biohazards:–

1. Toxicity to Soil: The majority of GM agricultural products are developed specifically for toxin-resistance - namely for higher doses of herbicides/ pesticides, but the herbicide use will triple as a result of GM products. Since the genetically modified plants have alternative ways to create photosynthesis, they are hyper-tolerant, and can thus be sprayed repeatedly without killing the crop. Though decaying in the soil, Roundup residues are left on the plant.

2. Soil Sterility and Pollution: In Oregon, scientists found GM bacterium, Klebsiella planticola meant to break down wood chips, corn stalks and lumber wastes to produce ethanol - with the post- process waste to be used as compost - rendered the soil sterile. It killed essential soil nutrients, robbing the soil of nitrogen and killed nitrogen capturing fungi (Elaine Ingham & Micheal Holmes, 1998. A similar research conducted on the GM bacteria Rhizobium melitoli in New York University showing the toxins that were lethal to Monarch butterfly are also released by the roots to produce soil pollution. The pollution was found to last up to 8 months with depressed microbial activity. An Oregon study showed that GM soil microbes in the lab killed wheat plants when added to the soil( Professor Guenther Stotzky, 1997).

3. Resistance breakdown: Disease or pest resistance conferred by a transgene can become ineffective. Many plant disease resistance genes are specific to particular pathogen strains. This means that growing such crops becomes, effectively, an ideal environment for the rare mutant in the pathogen or pest population that can overcome the resistance gene and that such mutants would prosper. Strategies to avoid, or at least delay, this outcome include the use of multiple resistance genes or the cultivation of small areas of susceptible crop varieties to provide refuges in which the non-resistant pathogen or pest may persist. As a result, resistance to the genetic modification will develop more slowly. However, the conventional use of pesticides sprayed on crops encourages resistance in a similar fashion. GM sources of resistance are therefore likely to be no different from conventional resistance genes. Resistance genes derived from BT, for example, are very specific in their ability to kill certain insect pests but are likely to be overcome by resistant insects in due course.

4. Super weeds: It has been shown that genetically modified Bt-endotoxin remains in the soil at least 18 months (according to Marc Lappe and Britt Bailey) and can be transported to wild plants creating super weeds - resistant to butterfly, moth, and beetle pests – potentially disturbing the balance of nature. A study in Denmark (Mikkelsen, 1996) and in the UK (National Institute of Agricultural Botany) showed super weeds growing nearby in just one generation. A US study showed the super weed resistant to glufosinate to be just as fertile as non-polluted weeds. Another study showed 20 times more genetic leakage with GM plants – or a dramatic increase in the flow of genes to outside species. Also in a UK study by the National Institute of Agricultural Botany, it was confirmed that super weeds could grow nearby in just one generation. The National Academy of Science's study stated that " concern surrounds the possibility of genes for resisting pests being passed from cultivated plants to their weedy relatives, potentially making the weed problem worse. This could pose a high cost to farmers and threaten the ecosystem." (quoting Perry Adkisson, chancellor emeritus of Texas A&M University, who chaired the National Academy of Science study panel). An experiment in France showed a GM canola plant could transfer genes to wild radishes, what persisted in four generations.

5. Super pests: Pests the transgenic cotton was meant to kill - cotton boll worms, pink boll worms, and bud worms - were once "secondary pests." Toxic chemicals killed off their predators, unbalanced nature, and thus made them more harmful pests.

6. Genetic Pollution: Genetic pollution is being used to describe the undesirable gene flow between GE species and wild relatives. Biologists using the term to describe the undesirable gene flow from domestic, feral, non-native and invasive species into wild indigenous species. Carrying GM pollen by wind, rain, birds, bees, insects, fungus, bacteria – the entire chain of life becomes involved. Once released, unlike chemical pollution, there is no cleanup or recall possible. As mentioned, pollen from a single GM tree has been shown to travel 1/5th of the length of the United States. Thus there is no containing such genetic pollution. Experiments in Germany have shown that engineered oilseed rape can have its pollen move over 200 meters. As a result German farmers have sued to stop field trials in Berlin. In Thailand, the government stopped field tests for Monsanto's Bt cotton when it was discovered by the Institute of Traditional Thai Medicine that 16 nearby plants of the cotton family, used by traditional healers, were being genetically polluted. US research showed that more than 50% of wild strawberries growing inside of 50 meters of a GM strawberry field assumed GM gene markers. Another showed that 25-38% of wild sunflowers growing near GM crops had GM gene markers. A recent study in England showed that despite the tiny amount of GM plantings there (33,750 acres over two years compared to 70-80 million acres per year in the US) wild honey was found to be contaminated. This means that bees are likely to pollinate organic plants and trees with transgenic elements. Many other insects transport the by-products of GM plants throughout our environment, and even falling leaves can dramatically affect the genetic heritage of soil bacteria. The major difference between chemical pollution and genetic pollution is that the former eventually is dismantled or decays, while the later can reproduce itself forever in the wild.

The research conducted by different scientists are showing that the GM crops are giving no more benefits to the mankind and nature as propagated by the companies, moreover it is deadly harmful to the ecology and the whole biosphere. So the works should be conducted more to convince the public and scientists to make aware about the future possible loss due to the application of these genetically modified organisms.