Genetic engineering not only allows this process to be dramatically accelerated in this report, it must be emphasized that GM crops grown to date have been .. effects, not least because many developing countries that could benefit from the. “To date, no adverse health effects attributed to genetic engineering have been A variety of hypothesized health risks posed by and benefits of GE crops are. Pros and cons of genetic engineering: 'Genetic engineering' is the process to alter the structure and nature of genes using techniques like cloning and.
Some secondary metabolites and other products such as proteins and peptides in commonly consumed plant materials can be toxic to humans when consumed in large amounts, and examples are listed below: Steroidal glycoalkaloids in green potato skin, which can cause gastrointestinal discomfort or, more severely, vomiting and diarrhea.
Oxalic acid in rhubarb, which can cause symptoms ranging from breathing difficulty to coma. Gossypol in cottonseed oil and cake, which can cause respiratory distress, anorexia, impairment of reproductive systems, and interference with immune function in monogastric animals. Nonprotein amino acid canavanine in alfalfa sprouts, which can be neurotoxic.
Hemolytic triterpene saponins in many legume species, which can increase the permeability of red blood cell membranes. Cyanogenic glycosides in almonds and cassava, which can cause cyanide poisoning.
Phototoxic psoralens in celery, which are activated by ultraviolet sunlight and can cause dermatitis and sunburn and increase the risk of skin cancer.
The Food and Agriculture Organization has recognized that foods often contain naturally occurring food toxins or antinutrients but that at naturally occurring concentrations in common diets they can be safely consumed by humans Novak and Haslberger, ; OECD, The health risks associated with some secondary metabolites in common foodstuffs are generally well understood, and the plants are either harvested at times when the concentrations of the compounds are low, the tissues with the highest concentrations of toxins are discarded, or, as in the case of cassava Manihot esculentathe food is prepared with special methods to remove the toxic compounds.
In other cases, food preparation may be the cause of the presence of a toxic compound for example, the formation of the probable carcinogen acrylamide when potatoes are fried at high temperatures or when bread is toasted.
Pros and Cons of Genetic Engineering
Plant breeders have generally screened for toxins that are typical of the plant group from which a crop was domesticated and have excluded plants that have high concentrations of the compounds. Unintended changes in the concentrations of secondary metabolites can result from conventional breeding Sinden and Webb, ; Hellenas et al.
In some cases, conventionally bred varieties have been taken off the market because of unusually high concentrations of a toxic compound, as in the case of a Swedish potato variety that was banned from sale in the s because of high concentrations of glycoalkaloids Hellenas et al.
Rather than being a cause of worry, many secondary metabolites are perceived as having potential health benefits for humans and are consumed in increasingly large quantities Murthy et al. Examples include the isoflavone phytoestrogens found in a number of leguminous plants, such as soybean Glycine max and clover Trifolium spp.
Pros and Cons of Genetic Engineering - Conserve Energy Future
Also, various perceived antioxidants, such as anthocyanins Martin et al. There is, however, disagreement as to whether many of the compounds are beneficial or toxic at the concentrations consumed in herbal medicines or dietary supplements see, for example, Patisaul and Jefferson, Crop plants naturally produce an array of chemicals that protect against herbivores and pathogens.
Some of these chemicals can be toxic to humans when consumed in large amounts.
In addition to the plant toxins, nutrients, introduced genes, and proteins and their metabolic products in specific GE crops are assessed with a comparative approach that is generally encompassed by the concept of substantial equivalence.
The concept of substantial equivalence has a long history in safety testing of GE foods. Foods derived from GM crops have been consumed by hundreds of millions of people across the world for more than 15 years, with no reported ill effects or legal cases related to human healthdespite many of the consumers coming from that most litigious of countries, the USA.
There is little documented evidence that GM crops are potentially toxic. A notorious study claiming that rats fed with GM potatoes expressing the gene for the lectin Galanthus nivalis agglutinin suffered damage to gut mucosa was published in Is there any a priori reason to believe that GM crops might be harmful when consumed?
The presence of foreign DNA sequences in food per se poses no intrinsic risk to human health. This would occur if the transgene coded for a toxin that was subsequently absorbed systemically by the host.Genetic Engineering : What Are the Advantages of Genetic Engineering?
However, the potential toxicity of the protein expressed in a GM food is an essential component of the safety assessment that has to be performed.
Allergies to non-GM foods such as soft fleshed fruit, potatoes and soy are widespread. Clearly, new varieties of crops produced by either GM techniques or conventional breeding both have the potential to be allergenic. Concern surrounding this topic relates to two factors; the possibility that genes from known allergens may be inserted into crops not typically associated with allergenicity and the possibility of creating new, unknown allergens by either inserting novel genes into crops or changing the expression of endogenous proteins.
Assessment of the allergenic potential of compounds is problematic and a number of different bodies have produced guidelines and decision trees to experimentally evaluate allergenic potential. In addition, animal models are used to screen GM foods. Two examples are frequently quoted regarding GM crop allergenicity: A project to develop genetically modified peas by adding a protein from beans that conferred resistance to weevils was abandoned after it was shown that the GM peas caused a lung allergy in mice 44 Soya bean engineered to express a Brazil nut protein was withdrawn from production after it was also found to be allergenic in tests.
It is perhaps a sobering thought, that if conventional plant breeding techniques had been used to achieve the same aims, there would have been no legal requirement for the assessment of allergenicity and the plant varieties could have been commercialized without in vivo testing.
Genetically modified plants and human health
However, GM technology might also be used to decrease the levels of allergens present in plants by reducing expression levels of the relevant genes. For example, research was recently undertaken to identify an allergen in soybeans and remove it using GM technology. In all cases, non-GM and GM approaches are both being developed. Of significance to the medical field is the use of GM plants for production of recombinant pharmaceuticals.
Molecular farming to produce GM plant-derived pharmaceutical proteins PDPs is currently being studied by academic and industrial groups across the world 4. The first full-size native human recombinant PDP, human serum albumin, was demonstrated in47 and since then antibodies, blood products, hormones and vaccines have all been expressed in plants.
As the molecular farming industry is still in its infancy, only one product has been approved for use so far — recombinant human intrinsic factor for use in vitamin B12 deficiency http: However, a number of molecular farming candidates are in clinical trials, including hepatitis B vaccine produced in potatoes and lettuce, 49 vaccines for heat labile toxin produced by E.
Genetically modified plants and human health
For example, GM plants can produce complex multimeric proteins such as antibodies that cannot be readily expressed by microbial systems. In addition, pharmaceutical production can potentially be on a vast agricultural scale.
These include topical application of antibodies and microbicides on mucosal surfaces for the prevention of infection. Not all applications need be on such a large scale; the hepatitis B vaccine is currently produced in genetically modified yeast, but not enough can be made at an affordable price to meet the demands of developing countries.
The current model of profit-motivated pharmaceutical production by companies in the developed world is ineffective in ridding the developing world of disease. GM plant technology may provide an alternative, as it is relatively low-tech and can be applied locally in the developing world by scientists working in partnership with governments and not-for-profit research funding agencies.
As with all aspects of GM crops, objections have been raised to the use of plants for manufacturing recombinant pharmaceuticals. Of greatest concern is that the pharmaceutical could inadvertently enter the human food chain. Theoretically, this might happen by uncontrolled dispersal of GM seed or by hybridization with a sexually compatible food crop following escape of GM pollen. Ina company called Prodigene was fined and was severely censured for breaches in safety regulation when, due to inappropriate removal procedures, GM maize expressing a PDP was found to be growing in a soybean crop destined for human food consumption in the next growing cycle.
More advanced forms of gene therapy attempt to correct the mutation at the original site in the genome, such as is the case with treatment of SCID.
Gene therapy using an adenovirus vector can be used to treat or cure certain genetic diseases in which a patient has a defective gene. Other trials have shown the clear hazards of attempting genetic manipulation in complex multicellular organisms like humans. Moreover, because viruses can often target multiple cell types, the virus vector may infect cells not targeted for the therapy, damaging these other cells and possibly leading to illnesses such as cancer.
Another potential risk is that the modified virus could revert to being infectious and cause disease in the patient. Four days after the treatment, Jesse died after a massive immune response to the adenovirus vector. Despite this information, it appears that neither Jesse nor his family were made aware of these outcomes when they consented to the therapy.
As a result, the regulation and oversight of gene therapy overall was reexamined, resulting in new regulatory protocols that are still in place today. Identify some risks of gene therapy. Oversight of Gene Therapy Presently, there is significant oversight of gene therapy clinical trials. At the federal level, three agencies regulate gene therapy in parallel: Along with several local agencies, these federal agencies interact with the institutional review board to ensure that protocols are in place to protect patient safety during clinical trials.
Compliance with these protocols is enforced mostly on the local level in cooperation with the federal agencies. Gene therapies are currently under the most extensive federal and local review compared to other types of therapies, which are more typically only under the review of the FDA.
Some researchers believe that these extensive regulations actually inhibit progress in gene therapy research. This raises questions such as: