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Here is a term paper on ‘Modern Biotechnology and Crop Improvement’ for class 9, 10, 11 and 12. Find paragraphs, long and short term papers on ‘Modern Biotechnology and Crop Improvement’ especially written for school and college students.
Term Paper Contents:
- Term Paper on the Aim of Modern Biotechnology
- Term Paper on Food and Crop Quality
- Term Paper on Genetically Modified Crops
- Term Paper on the Breeding Techniques for Crops
- Term Paper on the Regulation of Genetically Engineered Foods
- Term Paper on the Use of Antibiotic Resistance in Crops
1. Term Paper on the Aim of Modern Biotechnology:
The primary aim of modern biotechnology is to make a living cell perform a specific useful task in a predictable and controllable way. The task could be to ferment soya beans to make soya sauce or to breed a plant that has a higher yield or increased resistance to insect attacks.
Whether a living cell will perform these tasks is determined by its genetic make-up that is by the instructions contained in the collection of chemical messages found within its genes. These genes are passed on from one generation to the next so that offspring inherit a range of individual traits from their parents. In 1953, scientists discovered that deoxyribonucleic acid (DNA) is found in all living things and that a gene is a segment of DNA that has a specific sequence, or code, of chemicals.
This code determines various characteristics or traits such as eye or hair colour. In 1973, scientists identified a way to isolate genes and by the 1980s, they had developed the tools necessary to transfer genes from one organism to another. With the discovery of enzymes that could be used to cut or remove a gene segment from a chain of DNA at a specific site along the strand, scientists were able to introduce new instructions that would cause cells to produce needed chemicals, carry out useful processes or give an organism desirable characteristics. This technique is called “recombinant DNA” (rDNA) technology.
The result is modern biotechnology the science of transferring specific genetic instructions from one cell to another. In addition to transferring genes between species, it is possible to eliminate undesirable traits by switching off the genes responsible for these traits. This technology has been used to switch off the gene responsible for softening in tomatoes. In the future, it may even be possible to remove the proteins that may cause allergic reactions from foods such as peanuts and milk.
Traditional plant breeding techniques using the controlled pollination of plants have limitations. Firstly, sexual crosses can only occur within the same or related species. This limits the genetic sources breeders can depend upon to enhance desirable characteristics of plants. Secondly, when two whole plants are crossed, each having some 100,000 genes or so, all the genes from both plants get jumbled up.
This presents a problem as the plant offspring may express both desirable and undesirable traits of the parent plants. Because of this, breeders must spend years “back crossing” the jumbled up plants with the plant they started with, again and again, to slowly breed out the tens of thousands of genes they do not want.
Traditional plant breeding takes time, sometimes as long as 10 to 12 years. Plant biotechnology is an extension of traditional plant breeding with one important difference. Instead of mixing hundreds of thousands of genes to improve a crop plant, breeders can use modern biotechnology to select a specific trait from any plant, microbe or animal and move it into the genetic code of another plant.
This is possible because of the similarity of all living things at the DNA level. After the gene has been transferred, the newly modified plant exhibits specific modifications rather than the extensive changes that occur with traditional breeding.
Devastation of crops by insect pests is a major problem for farmers. To fight crop pests, farmers usually spray crops with insecticides. These sprays have limitations as they may degrade in sunlight or be washed away by rain. By introducing a specific gene into the genetic make-up of a plant, the plants are able to continuously produce proteins to protect against harmful insects. This built in protection offers farmers an alternative to the use of chemical pesticides.
When the usage of chemical pesticides is decreased, beneficial bacteria survive and, in turn, help control harmful insect pests.
Other potential benefits of insect-protected plants include:
1. Maintenance or improvement of crop yields.
2. Reduced exposure of farmers to chemical insecticides.
3. Soil protection.
4. Less exposure of ground water to chemical insecticides.
5. Lower levels of fungal toxins spread by insect damage.
Weeds compete with crops for water, nutrients, sunlight and space. They also harbour insect and disease pests, reduce crop quality and deposit weed seeds in crop harvests. Farmers fight weeds by tilling, using herbicides or through a combination of these methods. Tilling exposes valuable topsoil to wind and water erosion, and has serious long-term consequences for the environment.
Environmentally conscious farmers try to reduce tilling and limit the use of chemical herbicides. By introducing into a plant a gene that confers tolerance to a specific herbicide, a farmer can apply this herbicide in judicious amounts to control weeds without destroying the crop.
This technology allows the grower to apply herbicide only when the presence of weeds requires it, a practice consistent with the concept of integrated pest management. It may also result in the increased use of environmentally favourable herbicides and reduce the use of tilling.
Plant disease, including fungal and viral diseases, can devastate both the yield and quality of crop harvests. To minimize the economic loss resulting from plant disease, farmers often plant more than they expect to harvest. This increases the costs of planting and results in wastage of fuel, water and fertiliser.
In addition, farmers use chemical insecticides to destroy pests such as aphids that carry viral disease. Researchers are working to develop crops protected from certain types of plant viruses.
By introducing a small part of the DNA from a virus into the genetic makeup of a plant, scientists are developing crops that have in-built immunity to specific viral diseases. This allows reduced dependence on chemical inputs and improves both productivity and crop quality.
2. Term Paper on Food and Crop Quality:
Since the beginning of time, farmers have sought to improve the quality and quantity of food crops through plant selection and hybridization. By introducing a gene through genetic modification, beneficial changes may be made to plant crops.
The development of stronger crops would allow for increased food production in regions of the world where farming conditions are too severe for traditional crops. Increasing the nutritional content of staple foods could help certain populations get more nutrients without having to change their diets significantly.
Modern biotechnology has played a role in producing a variety of fermented foods that are commonly used in Asian diets. Traditional foods such as soya sauce, tempeh (fermented soya beans), belacan (fermented shrimp paste), cincaluk (fermented shrimps), budu (fermented fish sauce), tapai (fermented rice/tapioca), dadih (fermented milk), pickles, vinegar, bread, yogurt, and cheese are all products of fermentation. A wide range of additives, processing aids and supplements have also been obtained from microbial sources by fermentation such as vitamins, citric acid, natural colouring, flavourings, gums and enzymes.
Modern biotechnology is increasingly being used in fermentation. Genetically modified strains of microbes and enzymes have been used for several decades to bring about desirable changes in food products and processes. One of the most promising outcomes of the use of modern biotechnology is the production of a wide variety of food enzymes using microorganisms.
With food biotechnology, a greater range of pure and highly specific enzymes can be efficiently produced. These enzymes can be used to make desirable changes to food rapidly and at relatively low temperatures, with subsequent reduction in raw material and fuel requirements. Food safety is the assurance that a food will not cause harm when it is prepared or eaten according to its intended use.
The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) of the United Nations advocate the concept of ‘substantial equivalence’ as the most practical approach to address the safety evaluation of foods or food components derived by modern biotechnology.
This approach states that if a new food or food component is found to be substantially equivalent to an existing food or food component, it can be treated in the same manner with respect to safety. Researchers must prepare comprehensive data to support the safety and wholesomeness of new crop varieties developed through modern biotechnology. This process requires years of laboratory and field testing before a product can be brought to the market.
Conventional breeding techniques have been used for centuries to genetically alter various plant characteristics. In conventional breeding, neither the genes bearing the desired trait or the protein expression products of these genes are fully characterised. Introduction of genes through genetic modification procedures is more precise as the genes have been defined prior to their introduction. However, unlike conventional breeding, introduced genes can be obtained from almost any source, not just sexually compatible relatives of the food crop.
For this reason, regulatory agencies have required considerably more safety data for the introduction of new crop varieties developed through modern biotechnology than those developed via conventional breeding techniques.
To provide assurance that foods derived through modern biotechnology are as safe as those produced by traditional breeding programmes, the safety assessment strategies involve several key steps. These steps include molecular characterisation of the genetic modification, agronomic characterisation, nutritional assessment, toxicological assessment and safety assessment.
The overall goal of these tests is to determine whether the plant is substantially equivalent to food derived from a conventional source that has a history of safe use. A substantial equivalence evaluation focuses on the product rather than the process used to develop the product.
If the new product is substantially equivalent to the conventional food or feed, then the product derived through modern biotechnology is considered as safe as the conventional counterpart. If the food produced using modern biotechnology contains new traits which no longer make it substantially equivalent, such as a higher level of a vitamin, the assessment focuses on demonstrating the safety of the new trait.
Some safety assessment strategies are:
1. Molecular Characterisation:
For new plant varieties developed through food biotechnology, the source of the gene introduced into the plant is first identified. The transformation system used to insert the gene into the plant genome is defined, as well as the number of copies of inserted genes, and the integrity and stability of the genetic insert are determined.
2. Agronomic Traits:
Are usually the starting points for evaluating substantial equivalence? For example, in the case of potatoes, the traits commonly examined are yield, tuber size and distribution, dry matter content and disease resistance.
3. Nutritional Assessment:
Involve key nutrients including fats, proteins, carbohydrates and essential minerals and vitamins. Critical nutrients to be assessed are determined, in part, by knowledge of the function and expression product of the inserted gene. If, for example, an inserted gene expresses an enzyme that is involved in amino acid biosynthesis, then the amino acid profile would be determined.
4. Toxicology Assessment:
Toxicants and anti-nutrients are those compounds known to be inherently present in some crop varieties which could have an impact on health if the levels were increased significantly (for example, solanine glyco-alkaloids in potatoes or trypsin inhibitors in soybeans). The levels of anti-nutrients in genetically modified crops are compared to conventional varieties grown under comparable environmental and agronomic conditions.
5. Safety Assessment:
When a genetically modified food crop has been shown to be substantially equivalent to a conventional crop, the safety assessment focuses on the introduced trait and the protein expression product of the cloned gene. The biological function specificity and mode of action of the protein determine the key assessment undertaken.
If the protein is an enzyme, its potential effects on metabolic pathways and levels of endogenous metabolites are assessed. The amino acid sequence of the protein is compared to known sequences to determine if the protein has a sequence found in food proteins, toxins or allergens.
The inherent digestibility of the protein with simulated gastric and intestinal protease preparations is assessed and the level of expression of the protein in the food is determined. This assessment may be made on the appropriate raw agricultural product or a specific processed food component (such as oil).
Specific criteria have been developed to establish if the introduced protein is “as-safe-as” proteins already present in foods. Additional testing may be undertaken on a case-by-case assessment. Toxicological and nutritional endpoints can be evaluated in rat feeding studies to determine a “no-effect level” for anti-nutrient effects and compared to potential human exposures to determine if an adequate safety margin exists.
A small proportion of the adult human population (1- 2%) suffers from food allergies induced by immunologic reactions to foods such as eggs, milk, fish, shellfish, peanuts, soybeans, wheat and tree nuts. All food allergens are protein in nature, but most proteins do not elicit any allergenic effects in adults or children. Rigorous and comprehensive guidelines are in place at both the international and national levels to assess all foods for potential allergenicity before they are approved for public use.
In the case of foods produced using modern biotechnology, specific guidelines have been developed by leading organisations in food safety such as WHO, FAO and the U.S. Food and Drug Authority. Early allergenicity assessment focuses on the characterization of any protein produced as a result of introducing a new gene during genetic modification. The source of the protein, its history of safe use, the function of the gene/protein, its digestibility, stability to heat and other processes, are all used to compare the protein with known allergens.
Any potential safety issues are identified and a decision is made on whether to proceed further with developing the particular product. If the trait is considered crucial to assuring a supply of food through reliable crop production and the protein is found to be allergenic, a decision is commonly made to find alternative genes.
Based on over a decade of testing, it is now possible to reliably identify if a protein has the potential to be allergenic. Certain key principles underlie the selection and allergenicity testing of genetically modified foods.
These are:
1. The transfer of any known allergens is avoided.
2. An assumption is made that genes from allergenic sources will encode an allergen unless proven otherwise.
3. All introduced proteins are assessed for allergenicity.
The effectiveness of this testing scheme was demonstrated in the case of the Brazil nut 2S storage protein. This protein was introduced into soybean to increase the sulphur amino acid content and thereby improve its nutritional value. A small number of individuals who were allergic to Brazil nuts were tested to see if their blood samples cross-reacted with the Brazil nut 2S storage protein. Samples from eight out of nine individuals with allergy to Brazil nut reacted with this storage protein.
Plant breeders and farmers over the ages have selected plants that will either tolerate pests or be completely immune to them. This tolerance or immunity is conferred by the presence of genes that control the expression of certain cellular phenomenon, such as the production of substances which are toxic to the insects, fungi, bacteria or viruses concerned. Many of the modern agricultural crop varieties grown by farmers worldwide contain genes which confer resistance to pests.
The other way farmers control pests is by spraying chemicals on crops. Among the most common applications of modern biotechnology are plants that have been improved for their resistance to pest infestations and injury by plant disease. Examples include “B.t. crops”, and virus-protected crops.
This resistance helps avoid or reduce the need for insecticides. Natural evolution in pest populations means that some pests will eventually emerge that is able to tolerate either the herbicides or pesticides applied by farmers or, in the case of genetically modified crops, the inbuilt resistance in the crop.
Most strategies for delaying a pest’s ability to develop resistance have relied on reduced selection pressure on the pests to evolve. The most common method used by farmers planting genetically modified crops is to have a certain proportion of their farms planted to non-genetically modified crops so that not all insect pests are killed.
“Pyramiding” of several genes into the same crop variety is another method because pests have greater difficulty evolving to overcome this more complex form of resistance. Monitoring programs are another important component of resistance management strategies.
Antibiotics are chemical compounds capable of killing harmful bacteria. Many are natural substances produced by bacteria or moulds as part of their struggle for living space in their environments. In nature, bacteria develop resistance to antibiotics produced by other bacteria as a means of surviving their harmful effects.
This resistance is very specific and is genetically controlled by antibiotic-resistance genes. In modern biotechnology, antibiotic-resistance genes are used to make plant tissues resistant to a specific antibiotic so that this tissue can be clearly identified.
The tissue of interest commonly contains the useful trait that is desired in the particular crop. For example, during the research and development process, plant tissue containing a gene that allows a plant to produce more vitamins may be identified by being linked to an antibiotic-resistance gene.
When a population of tissue cells is exposed to a specific antibiotic, those cells containing the antibiotic resistance gene are able to be identified. Genetically modified plants commonly contain one antibiotic resistance gene to allow confirmation that the gene for the desired trait is present.
However, these plants do not contain antibiotics nor are they capable of producing any antibiotics. There is therefore no antibiotic in the food produced from genetically modified crops. Concern has been expressed about whether the use of antibiotic resistant marker genes will lead to an increase in antibiotic resistance in naturally occurring bacteria populations.
This is further spurred by concern that there will then be no drugs effective against certain harmful bacteria. The truth is that some 20-40% of bacteria typically contain some form of antibiotic resistance; otherwise they would not be able to compete with other bacteria.
Also, the two marker genes that are used in modern biotechnology confer resistance to old antibiotics, which are almost never used in human health care. These antibiotics were selected by scientists because of their relatively low likelihood of being used again for human health as new and more powerful antibiotics are now available.
Antibiotic- resistance genes work by producing proteins to protect plant cells from the specific antibiotic. These proteins have been shown to be easily broken down within seconds of being ingested and do not have any allergenic or toxic effects on humans or animal life.
In modern biotechnology, it is not the antibiotic that is incorporated in the plant tissues but the gene that confers resistance to the antibiotic. Transfer of this gene from a plant cell back to bacteria has not been shown to occur in nature. The safety of antibiotic-resistance marker genes has also been attested to by international organizations such as the Organization for Economic Cooperation and Development (OECD), WHO and FAO, after exhaustive testing over many years.
Nevertheless, in response to the concern about spreading antibiotic resistance among bacteria populations, scientists in several countries are working to identify new marker genes and also to remove antibiotic resistance marker genes from current products.
Modern biotechnology makes it possible to develop bacteria essential to herbicide and other pesticide compounds. Certain chemicals produced by these organisms are called allelopathic agents. These chemicals act as natural herbicides, preventing the growth of other plant species in the same geographic area.
Black walnut trees, for example, release an allelopathic agent against tomato plants. Modern high-yield agriculture entails consumption of vast amounts of chemicals for use as fertilizers and as agents to control pests and plant diseases, and any means that will permit the plant to do this work itself could result in significant savings for the farmer.
Chemical pesticide technology, bio pesticide technology is based on potent, naturally occurring proteins. These living particles are produced in nature by microorganisms such as Bacillus thuringiensis (B.t.). Discovered at the turn of the century, B.t. has been used without risk in the United States for almost three decades by home gardeners, farmers, and forestry officials.
Its active component, a protein, specifically attacks the stomachs of target pests, disrupting their digestive tracks so thoroughly that the pests stop eating and eventually die of starvation. Higher organisms, such as mammals, fish, birds, and other non-target species remain unthreatened, however, because their stomach acid easily breaks down the protein toxin. The delivery of these bio-pesticides varies in method and design.
In one method, dormant spores of B.t. are dusted on crops. The spores then become active and multiply, covering plants with bacteria poisonous to the target insects that feed on them. The B.t. toxin gene can also be inserted into the genetic makeup of crops, giving them a built-in resistance to insects.
Similarly, the toxin gene can be put into a third party, such as a microorganism that lives within the plant’s sap. These organisms known as endophytes multiply within the host plant and move throughout the plant’s vascular system, forming a microscopic defense against feeding insects.
This process resembles vaccines moving throughout a person’s vascular system to defend against harmful disease. Some of the concerns farmers raise about having to use increasingly dangerous pesticides to produce adequate crops may well be addressed by biotechnology.
Further research in agricultural biotechnology and bio-pesticide development aims to provide attractive alternatives to the farmer that will lower overall unit cost of production and allow the farmer to be more competitive in the highly cost-sensitive world markets. While some uses of chemical pesticides will be necessary for decades to come, continued development by biotechnology companies of useful biological pesticides will offer farmers viable alternatives.
3. Term Paper on Genetically Modified Crops:
Modern biotechnology may offer a way out of the dependence on unsustainable agriculture by eventually producing crop plants that enable agriculture to sustain yields but minimize environmental impacts.
But the perception in Europe is that some of the present generation of genetically modified (GM) crops, especially those developed for the US agricultural situations, which are herbicide-tolerant and insect-resistant, may present yet further risks to biodiversity in present intensive agricultural system. There are many genetic transformations in crops, such as altered starch, oil, and fat content, which will probably have little or no adverse impact on biodiversity.
Most of the present generations of GM crops carry transformations for the insertion of genes for herbicide tolerance and insect resistance into existing crop varieties. Comments will therefore focus on the genetically modified herbicide tolerant (GMHT) and genetically modified insect resistant (GMIR) crops which are closest to commercial use in Europe, but are being used commercially now over some 40 million hectares worldwide. Recent research confirms that genes introduced into some genetically improved crops will spread into related native species.
Gene transfer is almost inevitable from crops that have interfertile relatives in adjacent natural ecosystems, but not from crops such as the maize and cereals grown in Europe, whose closest relatives are on the other side of the oceans.
The difference of course is that genes inserted into GM crops are often derived from other phyla, giving traits that have not been present in wild plant populations, and if introduced accidentally, may change the fitness and population dynamics of hybrids between native plants and crops, eventually backcrossing into the native species and becoming established.
So the issue is not so much the rate of gene flow, rather the impact that this might have on agriculture and biodiversity. Conventional plant breeding, using mutagenesis and embryo rescue techniques, also produces lots of completely new genes in crops, about which we know very little. Interestingly, these are often the very crops being used by organic farmers and being sold as “natural foods”!
Most geneticists would argue that most “foreign” genes introduced into crop/native hybrids would in fact decrease their fitness in the wild, leading to rapid selection of these genes out of the population. This is particularly true of genes designed to prevent germination of saved seed, like the so called terminator gene if this were to “escape” it would commit instant suicide and certainly not spread into the natural world as has been suggested by some anti GM campaigners.
There is no difference to the farmer between buying seed with terminator technology and buying hybrid seed, because neither can be saved and grown next year. There is a serious issue about whether farmers in the developing countries should become locked into a cycle of dependence on patented seed, but the genetics of this technology is not a direct environmental threat. Transfer of certain genes, such as resistance to insects, fungi and viruses could increase fitness of any resulting hybrids, possibly forming aggressive weeds or plants that swamp wild populations.
Weeds having tolerance to a range of herbicides could also emerge; these would be difficult to control in agriculture, or in natural ecosystems like grasslands. Farmers may eventually need mixtures of herbicides to control them, causing yet more damage to biodiversity. There is already evidence from North America that this “multiple tolerance” and resistance to herbicides is beginning to emerge. If non-target plants acquired insect resistance from GM crops, they could damage food chains dependent on insects feeding on previously nontoxic wild plants.
Not only would there be a direct effect, for many insects are entirely dependent on single plant species, but acquisition of resistance in wild plants may change their population dynamics, increasing the risks of them invading agricultural land and natural ecosystems. These ecological genetics principles also apply to virus and fungus resistances.
This is an even more serious issue for developing countries where control of invasive plants is a major problem for subsistence farmers and may have implications for biotopes of global importance. The science we urgently need to be able to assess these risks is simply not being done.
At the moment we do not know what effect escaped genes might have on natural and farmland ecosystems. This lack of science is disturbing, given the commercial pressure and rapid timetable for the introduction of GM crops into landscapes. Science will never tell us everything about what might happen, but no science will tell us nothing.
Genetic transfer to native ecosystems not only carries ecological risk, but also undermines fundamental reasons for conserving plants and their dependent ecosystems in situ. Ecological genetics depends on research on gene pools of species making up native ecosystems, and the genetic code of each wild species holds information which may eventually benefit us.
So-called “genetic pollution” of native gene pools raises some legitimate questions about the loss of basic scientific resources. As scientists, we are keenly interested in the genetics of native populations, so to add genes from other phyla unwittingly and randomly to gene pools is not necessarily a good idea.
There is clearly a need to set up effective monitoring systems to detect gene transfer and research to assess ecological impacts. Research in this area would be in the interests of both the industry and the environment. It would be far better for biotechnology companies to produce the next generation of GM crop plants with in-built mechanisms, such as pollen incompatibility, to prevent gene flow.
Perhaps the ecologically simplest way to ensure genetic isolation is to make sure that wherever possible plants used for genetic modification are unrelated to native species and edible crops whose center of origin is within the intended market territory.
Modern biotechnology companies should start thinking now about which plants are chosen as platforms for biomedical and industrial product transformations. If modern biotechnology is ever to become a standard technique for plant breeding, predict that genetic isolation of crops from the rest of the living environment will become normal practice, as will the removal of certain genes such as antibiotic resistance.
At least two research programs in Europe and the United States have recently inserted novel genes into native species. One is concerned with inserting herbicide tolerance and genes for increased yield into native grasses, aimed at establishing monoculture high-output forage crops.
The other is aimed at inserting genes for insecticide immunity into predatory mites, so when a field is treated with insecticide the mites survive and set about mopping up any surviving pests. These developments greatly increase the risks of gene transfer and may run unacceptably high risks, because such genetically improved native organisms are completely cross-fertile with native species.
From a farmland management perspective, the long term prospect of having most pasture planted with herbicide-resistant grasses, and then sprayed to eliminate all other plants, could have devastating effects on remnant populations of wild plants, invertebrates, and birds that live in these agricultural grasslands.
There is also a real danger that such new varieties of native plants would be fitter than natives and colonize natural ecosystems with unpredictable results. This scenario is especially important in Europe, where we farm a much greater proportion of land than in the United States, and have less wilderness.
The UK and other European governments are committed to several international agreements to conserve wildlife, and we know we cannot do so solely by trying to protect isolated sites. This means that we need to farm in a way that allows biodiversity to thrive within farmland, alongside or within crops, unlike in the United States where intensively farmed areas are often quite separate from large protected wildernesses.
Why then are commercial companies and research institutions introducing agricultural biotechnology without assessing properly and holistically the potential risks and benefits to biodiversity?
Perhaps regulatory systems throughout the globe need to give some clear signals to the industry about where the boundaries between the possible and the unacceptable might lie. In other words, like in medical Research and Development (R&D), we may need an ethical framework to help science and industry to develop R&D strategies for different agro-ecosystems.
The prospect of gene transfer causes concern for crops that have wild relatives in the same ecosystem, and occupies reams of headline comment in the press. Perhaps of greater importance is the fact that management of some genetically improved crops would be very different from conventional intensive agriculture or organic farming. In the United States, genetically modified herbicide tolerant (GMHT) crops are grown under a regime of broad-spectrum herbicides applied during the growing season.
Farmers report almost total weed elimination from GMHT crops, which include cotton, soybean, maize, beet, and oilseed rape. They also report substantial reduction in herbicide use. Recent research in the United Kingdom confirms that weed control in GM beets and other GMHT crops is likely to become much more efficient.
These results are hardly surprising since this is the main purpose behind the technology. This GMHT system will soon be available, at least experimentally, for virtually all mainstream agricultural crops, including vegetables.
Broad-spectrum herbicides used on commercial scale GMHT crops during the growing season may be far more damaging to farmland ecosystems than the selective herbicides they might replace. Using these herbicides in the growing season may also increase the impact of spray drift onto marginal habitats such as ancient hedgerows and watercourses.
It is not only the volume of herbicides that is the issue but their efficiency and impact on wildlife. When insect resistance and herbicide tolerance are combined in the same crop variety, there may be few insects capable of feeding on the crops and few invertebrates and birds would be able to exploit the weed-free fields.
In Europe we already have massive declines in farmland birds, with several previously common species now close to extinction. The problem with assessing the environmental impact of these changes in management is that the regulatory system and the public has very little scientific data on which to assess the real risks, and potential benefits, from adopting GMHT crop systems. Formal risk assessments submitted by the biotechnology companies as part of the regulatory process deal with this issue inadequately.
In the United Kingdom, the Department of Environment, Transport and the Regions and the Ministry of Agriculture, Food and Fisheries have realized this, changed the regulatory system, and commendably have started some field-scale experiments to try to answer some of these important questions.
The development of new crops with improved tolerance to abiotic factors and the potential advent of ‘pharmed’ crops producing vaccines and GM biomass systems, may also change crop management, perhaps increasing demand for arable land in the long term, and putting further pressure on natural biodiversity on marginal land.
If we want to make predictions about how intensification enabled by GM crops could affect biodiversity, we can turn to evidence of declines in farmland plants, insects, and birds resulting from agricultural intensification in Europe over the past 30 years. Factors responsible include abandoning traditional crop rotations, increased pesticide efficiency and drift, use of artificial fertilizer, drainage, and intensification of soil cultivation.
There is overwhelming evidence demonstrating that the use of more effective pesticides over the past 20 years has been a major factor causing serious declines in farmland birds, arable wild plants, and insects. Pesticides not only have direct toxic effects on wildlife but they also enable modern crop management changes to take place.
Winter-sown crops rely heavily on effective fungicides. Thirty years ago winter sowing was unknown in the United Kingdom and winter stubbles were widespread, providing an essential food source for wintering flocks of birds. There are many examples of declines in farmland wildlife in the UK and these are typical of intensively managed farmland throughout Europe.
It is important to remember that although these declines in biodiversity have been severe in many intensively managed areas, there are still viable populations of many farmland- dependent species throughout Europe. Some of these, however, are only just surviving the impact of intensive agriculture.
More effective herbicides are responsible; similar trends have been observed elsewhere in Europe. Changes in herbicide practice have also been a major factor in reducing the distribution of insects such as the common blue butterfly, the larvae of which feed on broad-leaved weeds.
Over half of British farmland birds are now in serious decline and 13 are red-listed. The 78 percent drop in grey partridge numbers observed in the United Kingdom between 1972 and 1996, has been directly attributed to increased herbicide and pesticide efficiency.
Skylark populations have declined by 75 percent over this period mainly due to increased pesticide efficiency. Recent research implicates agricultural intensification in the decline of other songbirds.
Besides the aesthetic and scientific reasons for conserving biodiversity within and around agricultural crops, there is another important utilitarian reason for wanting to do so. This is the need to maintain the food chain links between native species and crop systems. This link is vital if we are to preserve the function of biodiversity to deliver early warning of dangers in crops or the chemicals used to manage them.
Without these links, are unlikely to be able to detect any dangers arising from the new agriculture by monitoring wildlife; the first organism in the food chain will increasingly be Homo sapiens. This “natural early warning system” has served agriculture and the public very well over the past 50 years.
It detected the toxicity of DDT and aldrin based organochlorine pesticides and showed up the potentially lethal effects of PCBs before toxic levels built up in humans. This is not just an issue for the industrial countries. It is a natural alarm system which is probably the most cost-effective way of monitoring environmental safety in developing countries.
Until research makes the ecological consequences of using new genetically modified crops clearer, the UK government, acting on advice from regulatory committees and statutory conservation agencies, have negotiated a delay in commercial releases of GIHT and GIIR crops for at least the next 3 years, to enable sufficient time for ecological research such as the present field scale trials to take place.
Information from such research can then be used by regulators to make more informed and publicly defensible decisions about whether GM crops should be commercialized, and under what conditions and in what environments. The delay also allows time to develop better regulations controlling where and how these crops may be grown.
In the United Kingdom there is currently no mechanism for on farm regulation of GM crops, but we believe that for some GM crops this should be put in place. Delaying commercial release could also allow development of better genetically improved crops with, for example, inbuilt safeguards against gene transfer. The crops coming to commercialization today are the first generation of new biotechnology products.
4. Term Paper on the Breeding Techniques for Crops:
Conventional breeding technique is the basis for the development of essentially all varieties of plants and animals used in agriculture today. But the biggest problem is that a desirable characteristic being sought to improve a given species may not be found among any of the plants or animals of that species in the world.
The source for genetic resources is expanded to include all living species, making the possibility of improvements virtually unlimited. Modern techniques fall into three categories: cross-breeding between species, cell fusion, and genetic engineering. The reproductive process through which genetic material is transferred between individuals of a species does not normally work between species.
The desire to improve certain crops, however, has led plant breeders to develop processes for interspecific hybridization to transfer genes from one plant to another plant of a related species. This transfer has been accomplished during the last 80 years only through the discovery of efficient ways to circumvent the natural barriers to the exchange of genetic information between species.
The processes for interspecific gene transfers are usually laborious, time consuming, and quite often unsuccessful. There are many steps in the process of developing a hybrid plant, and each step is a possible point for failure, either through death or sterility of the plant.
Even when a hybrid plant is created, there is a possibility that undesirable traits that affect crop quality, yield, or adaptation to stress may be transferred along with the desirable trait.
Even with all of these problems, interspecific hybridization has been responsible for many improvements in the tolerance of crops to physical stresses, resistance to diseases and insects, and increased yield potential for certain crops. The process has even made possible the development of a new grain crop, triticale, from the hybridization of wheat and rye.
Microbiologists and breeders have been looking for alternate means to transfer genes. Such exchange of genes depends on the scientist’s ability to regenerate a plant from tissues or organs. Much effort has been devoted to cell fusion, a process for combining two cells of the same or different species in the presence of certain chemicals or electrical current.
In addition to the problem of regenerating a complete plant from the resulting cell, it is often difficult to achieve a stable hybrid because of incompatibility between the parent species. As with interspecific hybridization, many genes are transferred during the cell fusion process, and thus unwanted traits may be transferred with the desirable ones. Further crosses may be necessary to obtain plants with the desired combination of parental traits.
i. Genetic Engineering:
Genetic engineering may help crop producers reduce dependence on pesticides by affecting the plant’s resistance or tolerance to pests in the field. It can also affect production efficiency and profitability by improving the climatic adaptation of the plant and by enhancing the postharvest storability of the product.
Genetic engineering can speed up the process of developing resistant varieties and potentially can introduce genes that will provide new ways for plants to withstand pests. There has been much interest in using genetic engineering for insect control. The interest in developing insect-resistant varieties results from the desire to reduce the extent of pesticide use and to avoid the development of pesticide resistance in some of the important insect pests.
The development of crops with insect resistance is not a new idea. Classical breeding programs have been developing varieties with insect and disease resistance or tolerance for many years. The problem has been that insects are generally able to overcome the resistance in 2 to 10 years.
Another aim of modern biotechnology in insect control is to provide materials that are selective, will not affect non-target species, and to which insects will not easily develop resistance. Much of the work to date has focused on applications of Bacillus thuringiensis (Bt), an insect control bacterium, but other approaches are being explored as well.
Bt has been used as a bio-control agent for 20 years. It is a naturally occurring bacterium that produces protein crystals that are toxic to insects. These proteins are very specific insecticides with activities against some species of caterpillars, mosquitoes, flies, and beetles. Recent research on Bt has followed two approaches.
The first is the selection and development of Bt strains that are specific for other pests or that produce higher concentrations of the compounds. Different strains of Bt to control plant and animal parasitic nematodes, animal- parasitic liver flukes, protozoan pathogens, and mites have been identified.
The second approach is to move the gene that controls the production of the Bt proteins into crop plants. Bt genes for control of an insect species have been incorporated into tomatoes, tobacco, cotton, and corn with good results. Bt proteins are highly specific to particular insect species. Therefore, to achieve control of several different insect species at one time, many different gene codes would have to be incorporated into the plant’s genetic makeup.
The incorporation of Bt genes into plants causes concern that insects will likely develop resistance to the Bt strain. The probability is especially high in current cases where the gene is expressed throughout the plant. If three to four generations of an insect feed on the plant leaves or fruits throughout the growing season, the insect would be constantly exposed to the chemical.
It is likely that the insect will develop resistance to the chemical. It may become possible to direct the expression of the Bt products to only the fruit tissues, meaning that only one generation of insects would be exposed.
It may also become possible to incorporate the genes in such a way that they are expressed only after an insect begins to feed on the plant. Finally, several different Bt genes may be introduced at one time, making the development of resistance more difficult.
ii. Weed Control:
In the near future, biotechnology will probably influence weed control in at least four ways. The first is through the production of bio-herbicides. Bio-herbicides are fungal or bacterial products selected for their ability to cause disease in specific plants, such as weeds, without harming desirable plants.
They may be applied in the same manner as conventional herbicides. At present, two bio-herbicides are being marketed for the control of specific weeds that are normally hard to control: DeVine for control of strangler vine in Florida citrus and College for control of northern joint vetch in rice and soybeans in Arkansas, Louisiana, and Mississippi.
DeVine has been so successful in destroying strangler vine that the market for the product has almost been lost. The reason for its great effectiveness is that the product remains in the soil and gives 95 to 100 percent control for 6 to 10 years after a single application.
There are other bio-herbicides in various stages of research and development for such things as control of prickly soda in cotton and soybeans, control of sickle-pod in cotton and soybeans, control of spurred anode in cotton, control of velvetleaf, and growth suppression of water hyacinth.
Biotechnology will play a major role in helping overcome problems in manufacturing these bio-herbicides by the development of better fermentation processes, as well as assisting in the isolation of the genetic determinants of virulence, specificity, sporulation capacity, toxin production, and tolerance to climatic stresses.
A second application of biotechnology that shows promise is the development of microbial and secondary plant products for use as herbicides. Much effort has been devoted to determining the actual compounds associated with allelopathy. Many of these compounds have limited selectivity and a lack of stability.
However, one herbicide derived from chemicals found in a naturally occurring microbe is being marketed in Japan. Herbiaceae exhibits strong herbicidal activity against a wide spectrum of grass and broadleaf weeds when it is applied to foliage.
A more important role for these compounds is to provide models for the development of new chemicals that could be produced as commercial herbicides. It may be possible to produce synthetic derivatives of these chemicals that are more stable under field conditions, have greater selectivity than the natural chemicals, or have other advantages over the original chemicals.
Several companies have developed chemicals based on this natural herbicide chemistry. It is believed that the naturally occurring herbicides will be safer for the environment because many of them are degraded rapidly in the soil. Concerns have been raised about these developments.
One is that development of herbicide resistant or herbicide-tolerant crop varieties may lead to overdependence on herbicides. Many of the herbicides being used for the development of crop herbicide resistance are broad spectrum, low-mammalian-toxicity chemicals that are thought to be safer for the environment than conventional herbicides.
However, attempts are also being made to develop varieties with resistance to certain other compounds, such as atrazine, that are more persistent and have been found in groundwater in certain areas of the United States. Continued use of these older chemicals, ones that tend to persist in the soil and may move into groundwater, could cause environmental problems.
Associated with the exclusive use of one herbicide for weed control in each crop in a rotation is the possible development of herbicide-resistant weeds. There are already over 100 species of weed plants known to have developed resistance to one herbicide or another.
Much of this resistance has resulted from the continual use of one type of herbicide increasing the probability of developing resistant plants within the weed population. The use of a comprehensive weed control program, including rotating chemicals based on their mode of action, should allow the successful use of the new, “safer” herbicides.
Another concern is the possible movement (outcrossing) of the “engineered” genes from the host plant to related weed species. This possibility has not received much attention in the United States because in most cases our weed species are not closely related to crop species.
An exception is the vegetable industry in California because many of the vegetable crops have closely related weed relatives in the wild. On the other hand, the possibility of outcrossing may not be very likely, considering the lengths to which plant breeders had to go to accomplish interspecific hybridization before genetic engineering was introduced. Control of disease is a subject of great interest for biotechnologists.
The majority of advances have been in control of viral diseases. Because most viruses are spread mechanically or through insect vectors, control efforts have traditionally revolved around control of the vectors and destruction of diseased plant material. Viruses are composed of two parts—the viral DNA and a coat protein that surrounds the viral DNA.
Researchers have known about the phenomenon of cross-protection: that infection of a plant by a mild strain of virus can often protect the plant from a serious infection by a more virulent related strain. The researchers have recently discovered that it is the presence of the coat protein that restricts the infection by the virus in cross-protection.
By incorporating the genes for the coat protein into the plant it is possible to have the plant itself produce low levels of the coat protein. These low levels of the coat protein delay or restrict infection of the plant by the virus.
Cross-protection via gene transfer offers a number of advantages. The first is that the protection is essentially permanent, similar to that afforded animals by vaccines. The need for the use of chemicals to control insect vectors is also reduced. Other possible aspects of disease control in which modern biotechnology may play a role include the use of plant disease bio-control fungi and the development of fungal resistance in plants.
Plant disease bio-control fungi are naturally occurring organisms that are antagonists for certain soil-borne plant pathogens. Biotechnology will play a role in better understanding the mechanisms for host specificity and virulence of these fungi and may lead to the production and formulation of control products.
Fungal resistance is an area of interest, but no great progress has been made yet. Modern biotechnology will enhance our understanding of the mechanisms that control a plant’s ability to recognize and defend itself against disease-causing fungi.
Although modern biotechnology efforts have focused primarily on pest management, there are other potential applications to crop production. The possibilities are highly varied, and new applications are developing so quickly that it is difficult to keep up with all of them. Here are a few examples of current biotechnology research on plants.
Plant breeders have long been interested in modifying components of crop products, such as the amount of various amino acids contained in the proteins of corn used for human and animal feeds. Traditional breeding has developed cultivars with high concentrations of lysine, an essential amino acid.
The increase in lysine content, however, was accompanied by a 10 percent decrease in yield. Scientists are working to incorporate a gene in corn that will increase the amount of lysine without the associated yield decrease. They have also developed corn with higher-than-usual oil content for use as a source of vegetable oil and feed.
5. Term Paper on the Regulation of Genetically Engineered Foods:
Modern biotechnology products are regulated primarily by three federal authorities- the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), and the U.S. Department of Agriculture (USDA). The FDA has jurisdiction over new human and animal drugs as well as older drugs produced in new ways.
The FDA also has jurisdiction in ensuring the safety of new foods and of new or increased amounts of substances in foods or food additives. The EPA has jurisdiction over any product that may have pesticide properties and for any new chemical substance for introduction into the U.S. market that is not regulated under any other statutory authority.
The USDA has broad statutory powers to regulate agricultural research and agricultural products to protect crops and livestock from pests, disease, or harmful plants. Along with the federal regulation, several states, including North Carolina, have also developed legislation to control certain aspects of biotechnology.
North Carolina was one of the first states to formulate and enact legislation specifically regulating modern biotechnology. The North Carolina Genetically Engineered Organisms Act regulates the release into the environment and the commercial use of genetically engineered organisms.
The state law, administered by the North Carolina Department of Agriculture (NCDA), requires that a permit be obtained from the NCDA for field testing of genetically engineered microbes, plants, or animals. Organisms produced by traditional breeding methods, such as hand pollination of crop plants and artificial insemination of animals, do not require a permit.
The law and regulations are formulated to work with existing federal regulatory procedures, and the NCDA cooperates with federal regulatory agencies in the permit review process. The legislation regulating modern biotechnology must address the concerns of the general public, farmers, and the business community.
Modern biotechnology offers increased opportunities for improving or developing food production systems, especially from an environmental standpoint. Moreover, the potential benefits extend to improving the nutritional quality, safety, flavor, convenience, and cost of the food supply.
However, acceptance by both regulatory agencies and consumers will depend on ensuring that foods resulting from the application of modern biotechnology are indeed safe to eat. To suggest that we should not be concerned about the safety of these foods would be misleading.
Any changes in the composition of foods or in the methods used to handle, process, preserve, and distribute them must be evaluated to determine their impact on food safety. However, we must be careful not to exaggerate the safety issue beyond its true dimensions. We must remember that all of our food has been genetically modified through the years. The U.S. Food and Drug Administration, in late May of 1992, announced its policy for foods derived from genetically engineered plant varieties.
In essence, the policy statement reaffirmed that genetically engineered foods will be judged on the characteristics of the food and not on how the plant genes may have been manipulated. The policy also stated that the anticipated regulatory approach will be “identical in principle” to that applied to foods – genetically modified by traditional plant breeding practices.
Thus, it appears that the FDA views the safety considerations for genetically engineered products to be no greater than for products genetically modified by traditional practices. The FDA’s policy on the regulation of genetically engineered foods should not be viewed as fixed.
Modern biotechnology promises many potential benefits for farmers and consumers. We will achieve these benefits, however, only if the public accepts biotechnology as ethical and safe. Because genetic engineering is new and complex, people may see it as mysterious and controversial.
Public opinion could have an important influence on the future direction of modern biotechnology. Modern biotechnology is developing within a larger context of consumer concerns about health and environmental problems, especially those attributed to technology. Consumers increasingly express concern about food safety.
In particular, the public perceives certain agricultural practices as potentially dangerous. The use of biotechnology in agriculture and food production could elicit concerns similar to those expressed about agricultural chemicals. In addition, other dimensions of biotechnology are also starting to draw public attention.
Current techniques of developing organisms used in the production of BD foods typically involve the transfer to the host of the desired gene or genes in combination with a promoter and a gene for a selectable marker trait that allows the efficient isolation of cells or organisms that have been transformed from those that have not.
Common selectable markers in plants have included resistance to antibiotics (kanamycin/neomycin or ampicillin) or herbicides. Several key issues have been raised with respect to the potential toxicity associated with BD foods, including the inherent toxicity of the transgenes and their products, and unintended effects resulting from the insertion of the new genetic material into the host genome.
Unintended effects of gene insertion might include an over expression by the host of inherently toxic or pharmacologically-active substances, silencing of normal host genes, or alterations in host metabolic pathways.
It is important to recognize that, with the exception of the introduction of marker genes, the process of genetic engineering does not, in itself, create new types of risk. Most of the hazards listed above are also inherent in conventional breeding methods.
The guiding principle in the evaluation of BD foods by regulatory agencies in Europe and the USA is that their human and environmental safety is most effectively considered relative to comparable products and processes currently in use. From this arises the concept of “substantial equivalence.”
If a new food is found to be substantially equivalent in composition and nutritional characteristics to an existing food, it can be regarded as being as safe as the conventional food and does not require extensive safety testing.
Evaluation of substantial equivalence includes consideration of the characteristics of the transgene and its likely effects within the host, and measurements of protein, fat and starch content, amino acid composition and vitamin and mineral equivalency together with levels of known allergens and other potentially toxic components.
BD foods can either be substantially equivalent to an existing counterpart, substantially equivalent except for certain defined differences, or be non-equivalent, which would mean that more extensive safety testing might be necessary. The examination of substantial equivalence therefore may only be the starting point of the safety assessment.
It provides a valuable guide to the definition of potential hazards from BD foods and illuminates necessary areas for further study. While there is some concern relative to the meaning of “substantial” and how equivalency should be established, and debate over its use continues, the concept appears to be logical and robust in assessing the safety of foods derived from both genetically-modified plants and microorganisms.
If it can be established with reasonable certainty that a BD food is no less safe than its conventional counterpoint, it provides a standard likely to be satisfactorily protective of public health. It is also an approach that has the flexibility to evolve in concert with the field of transgenic technology.
A recent study of FDA procedures for assessing the safety of BD foods by the US General Accounting Office reviews these procedures and concludes that the current regimen of safety tests are adequate to assess existing BD foods.
6. Term Paper on the Use of Antibiotic Resistance in Crops:
Bacteria are microbes that are present everywhere in the environment and in plants and animals. Microbes occupying the same habitat compete for nutrients and for their own survival some have evolved naturally to produce antibiotics to eliminate their competitors. Antibiotics inhibit a cell’s growth by blocking some of its essential metabolic processes.
Bacterial strains producing a given antibiotic therefore have to carry resistance to inactivate the corresponding antibiotic and thus prevent its own self- destruction. In the evolutionary race between microbes the production of new antibiotics is usually countered through the development of resistance mechanisms both by producing-and target-organism.
There is in nature a wide range of antibiotic and corresponding antibiotic genes. However, rather than developing their own resistance mechanisms, targeted bacteria will in general acquire antibiotic resistance genes which are already present in the bacterial pool surrounding them.
This is facilitated due to the fact that bacteria are generally quite promiscuous about exchanging genetic material between each other. The presence of an antibiotic confers an advantage to a resistant bacterium and so under these conditions resistance development and spread increases.
The discovery of antibiotic action against disease- causing agents at beginning of the 20th century had a major impact on medicine. However, it has been used without sufficient limitation. Man’s use of antibiotics has drastically increased their global distribution and consequently promoted the spread of resistant microbes.
Increased use of antibiotics in clinical and also veterinary medicine is the major cause of the increasing incidence of antibiotic resistance in bacteria. In addition, antibiotics have been and still are used extensively as animal feed additives which have brought about the selection of resistant bacteria in healthy animals. Antibiotics are also widely sprayed on crop plants, orchards, vines, etc. to protect against pathogens.
Today resistance to antibiotics is so widespread that some of the first generation of antibiotics is of no use anymore. Multiple antibiotic resistances in pathogenic strains of Staphylococcus and Mycobacterium tuberculosis, especially in hospitals, are of particular concern to the medical community.
Concern about the use of antibiotic resistance markers in relation to overall antibiotic use management is expressed. Since the mid-1980s modern biotechnology methods have been developed to improve agricultural crops through the introduction of genetic material that confers advantageous characteristics.
There are two types of antibiotic resistant marker (ARM) genes used in transgenic plants:
a. Genes Driven by Bacterial Promoters:
These genes have been used during the initial stages of the assembly of the pieces of DNA intended for transfer into the plant cells. The purpose of these genes was to select for the amplification of the pieces of constructed DNA in the receiving bacteria. The gene providing resistance to ampicillin belongs to this category.
Genetically modified plants containing those genes are from the earliest generation of technologies and present technologies only allow the removal of these genes before initiating the plant transformation process.
b. Genes which allow the Selection of Plant Cells which have up taken the Piece of DNA Carrying the Trait or Characteristic of Interest:
The insertion of a gene into a plant cell by transformation is a very inefficient process since only a few thousand cells of the many millions used take up the desired gene. The transfer of an antibiotic resistance marker gene together with the gene of interest allows these very few cells to be selected as only those cells that have taken up both genes will survive and multiply in the presence of the corresponding antibiotic in the growth medium. A genetically modified plant is then grown from these modified cells and the marker is no longer needed.
The time needed for the development of a genetically modified crop with a new trait usually exceeds 10 years. Safety aspects are taken into consideration at each step of product development. This starts at the selection of appropriate proteins and genes to insert into the plant, followed by experiments designed to assess potential impacts on human health from the consumption of the GM crop and then several years of field trials with the genetically modified crop to assess potential environmental safety impacts.
Antibiotic resistance markers used in the development of genetically modified crops have been selected by scientists according to various safety criteria.
These include that the marker genes occur frequently in natural microbial populations and that they confer resistance to a narrow range of specific antibiotics with limited application in human and veterinarian medicine. The most widely used antibiotic resistance marker for the selection of transformed plant cells is the nptII gene, also called aph(3′)-II, which confers resistance to the antibiotics neomycin and kanamycin.
This gene is present in ten of the fourteen GM plants containing antibiotic resistant marker gene submitted for marketing in the EU.
For example, it has been used to develop the delayed ripening tomato, herbicide-tolerant and insect-protected corn and cotton varieties. The choice of using this antibiotic resistant marker gene has been driven by the fact that the antibiotics kanamycin and neomycin are not important in medical treatment and that, on average, 20 to 40% of the bacteria that occur naturally in human or animal digestive tracts are already resistant to kanamycin. Kanamycin/ neomycin resistant bacteria are ubiquitous in nature, their prevalence being dependent upon the source of the bacteria isolated, the highest level being found in pig manure.