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Ecological Considerations in the Release of Transgenic Plants |
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Ecological Considerations in the Release of Transgenic Plants
Biotechnology research which began in the seventees of this century has now begun to yield fruitful results in industrial pharmaceutical, agricultural and veterinary fields. Currently, there are about 1500 companies operating in the U.S.A alone. The first pharmaceutical product to come out was insulin and the first agricultural biotechnology product was a swine vaccine.
Since that time over 2000 transgenic plants and microorganisms have been released in the world depending upon how one defines the word 'release' in each country and the rules pertaining to releasing a product.
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The commercial use of engineered plants or microorganisms is the largest in China, especially tobacco and tomato. In the U.S.A, as mentioned earlier, a transgenic Pseudomonas to which a toxic gene from Bacillus thuringiensis has been added is being commercially distributed. Transgenic plant products such as tomatoes and cotton have been approved and tomatoes have been marketed since 1994.
From the current information available with the USDA, it is gathered that the following transgenic crops, with the altred phenotypes indicated in parenthesis, have the approval of USDA for unristricted planting
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Beet (Glufosinate and glyphosate tolerant); com (lepidopteran resistant and glyphosate tolerant); cotton (lepidopteran and herbicide tolerant); flax (Sulfonylurea tolerant); melon (delayed ripening); papaya (PRSV resistant); potato (insect resistant); rape (oil profile altered, male sterile and herbicide tolerant); rice (Glufosinate tolerant); soybean (herbicide tolerant, oil profile altered); squash (virus resistant) and tomato (fruit ripening altered and lepidopteran resistant).
The definitions of a microorganism or a recombinant microorganism are not clear. Description and scope covered by the term microorganism rather than its definition per se appears to be more important.
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The European union has recently decided to use the term 'Biological material' in place of microorganism. Similarly, to decide when a sufficient modification has occurred from the original microorganism to call it a genetically engineered organism (GEO) has also been a debatable issue. Secondly, deciding the appropriate stage when the product could be released is dependent upon field trials for the particular product in one location or many locations (presently size of plots ranging from 0.25 to 10.0 acres) and the attendant assessment of the overall risks involved for the society.
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The first successful field test of an engineered organism was a bacterium capable of resisting frost injury carried out in 1986. Since that time over 2000 field tests of plants and microorganisms have been conducted in the U.S.A by academicians as well as company managers. Many developed countries have designed protocols for field testing, reviewing and legislation to deal with GEOs. UNIDO has drafted a voluntary code for underdeveloped countries where no such regulations exist.
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The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) regulates the introduction of genetically modified organisms which are or may be derived from plant pests or which are used in veterinary products such as vaccines. APHIS has established a division called Biotechnology, Biologics and Environmen¬tal Protection (BBEP) which overseas the regulatory process and provides a circle of protection to safeguard American agriculture. APHIS was the first federal agency to promulgate a set of codified rules governing the introduction of genetically engineered plants and microorganisms.
The reactions of public or the common man to the release of GEO or a transgenic plant are vital; for example, in the U.S.A, India, Germany and Holland transgenic plants have been uprooted and demonstrations held against the introduction of foreign genes into naturally growing plants. Such reactions are mostly based on the lack of knowledge of potential risks involved in planting transgenic plants fuelled by such disasters as Chernobyl nuclear spill over. On the contrary, it was found in a public survey that over 60 per cent of people in the U.S.A. believe that genetically engineered products would usher in the desired change and that hardly 19 per cent of people had really the knowledge needed to perceive the potential risks involved. A recent survey in the U.S.A. revealed that 94 per cent of people felt that the benefits were worth the risks involved.
Will genes from transgenic plants get transferred to other related or unrelated crops or weeds? Will pollinations result in viable progeny? Will the resulting progeny persist, be more aggressive, invasive and persistant than the parent crop? Is it likely that the DNA in transgenic plants transform other forms of life? Is it possible that while insects pollinate transgenic plants (via pollen) or while earthworms graze plant debris or vertebrates consumes them, the gut microflora of these living beings get modified? What happens to DNA from the remains of transgenic plants bound to soil particles?.
The answers to the above questions have not come in a large measure eventhough some indications are available to demonstrate that nontarget effects may occur unintentionally. However, these results have come from small scale studies but answers to many other ecological issues arising out of large scale introduction of transgenic plants must come from experience as we learn increasingly from future field trials which are now currently estimated at 400-600 in the U.S.A and hundreds of similar tests in India, Canada, Europe, New Zealand, Australia ane Latin America involving about 24 to 36 plant species. The largest number of tests conducted in the U.S.A relate to herbicide tolerance followed by insect and virus resistance tests involving tomatoes, cotton, potatoes, soybeans, tobacco, com and alfalfa.
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