The Experts below are selected from a list of 14946 Experts worldwide ranked by ideXlab platform
Stuart J. Smyth - One of the best experts on this subject based on the ideXlab platform.
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us regulatory system for genetically modified genetically modified organism gmo rdna or Transgenic Crop cultivars
Plant Biotechnology Journal, 2007Co-Authors: Alan Mchughen, Stuart J. SmythAbstract:Summary This paper reviews the history of the federal regulatory oversight of plant agricultural biotechnology in the USA, focusing on the scientific and political forces moulding the continually evolving regulatory structure in place today. Unlike most other jurisdictions, the USA decided to adapt pre-existing legislation to encompass products of biotechnology. In so doing, it established an overarching committee (Office of Science and Technology Policy) to study and distribute various regulatory responsibilities amongst relevant agencies: the Food and Drug Administration, Environmental Protection Agency and US Department of Agriculture. This paper reviews the history and procedures of each agency in the execution of its regulatory duties and investigates the advantages and disadvantages of the US regulatory strategy.
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us regulatory system for genetically modified genetically modified organism gmo rdna or Transgenic Crop cultivars
Plant Biotechnology Journal, 2007Co-Authors: Alan Mchughen, Stuart J. SmythAbstract:Summary This paper reviews the history of the federal regulatory oversight of plant agricultural biotechnology in the USA, focusing on the scientific and political forces moulding the continually evolving regulatory structure in place today. Unlike most other jurisdictions, the USA decided to adapt pre-existing legislation to encompass products of biotechnology. In so doing, it established an overarching committee (Office of Science and Technology Policy) to study and distribute various regulatory responsibilities amongst relevant agencies: the Food and Drug Administration, Environmental Protection Agency and US Department of Agriculture. This paper reviews the history and procedures of each agency in the execution of its regulatory duties and investigates the advantages and disadvantages of the US regulatory strategy.
Alan Mchughen - One of the best experts on this subject based on the ideXlab platform.
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us regulatory system for genetically modified genetically modified organism gmo rdna or Transgenic Crop cultivars
Plant Biotechnology Journal, 2007Co-Authors: Alan Mchughen, Stuart J. SmythAbstract:Summary This paper reviews the history of the federal regulatory oversight of plant agricultural biotechnology in the USA, focusing on the scientific and political forces moulding the continually evolving regulatory structure in place today. Unlike most other jurisdictions, the USA decided to adapt pre-existing legislation to encompass products of biotechnology. In so doing, it established an overarching committee (Office of Science and Technology Policy) to study and distribute various regulatory responsibilities amongst relevant agencies: the Food and Drug Administration, Environmental Protection Agency and US Department of Agriculture. This paper reviews the history and procedures of each agency in the execution of its regulatory duties and investigates the advantages and disadvantages of the US regulatory strategy.
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us regulatory system for genetically modified genetically modified organism gmo rdna or Transgenic Crop cultivars
Plant Biotechnology Journal, 2007Co-Authors: Alan Mchughen, Stuart J. SmythAbstract:Summary This paper reviews the history of the federal regulatory oversight of plant agricultural biotechnology in the USA, focusing on the scientific and political forces moulding the continually evolving regulatory structure in place today. Unlike most other jurisdictions, the USA decided to adapt pre-existing legislation to encompass products of biotechnology. In so doing, it established an overarching committee (Office of Science and Technology Policy) to study and distribute various regulatory responsibilities amongst relevant agencies: the Food and Drug Administration, Environmental Protection Agency and US Department of Agriculture. This paper reviews the history and procedures of each agency in the execution of its regulatory duties and investigates the advantages and disadvantages of the US regulatory strategy.
Henri Darmency - One of the best experts on this subject based on the ideXlab platform.
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fitness of backcross six of hybrids between Transgenic oilseed rape brassica napus and wild radish raphanus raphanistrum
Molecular Ecology, 2002Co-Authors: Gaelle Gueritaine, Martina Sester, Frederique Eber, Anne-marie Chèvre, Henri DarmencyAbstract:The process of introgression between a Transgenic Crop modified for better agronomic characters and a wild relative could lead potentially to increased weediness and adaptation to the environment of the wild species. However, the formation of hybrid and hybrid progeny could be associated with functional imbalance and low fitness, which reduces the risk of gene escape and establishment of the wild species in the field. Our work compares the fitness components of parents and different types of backcross in the sixth generation of hybrids between Transgenic oilseed rape ( Brassica napus , AACC, 2 n = 38) resistant to the herbicide glufosinate and wild radish ( Raphanus raphanistrum, RrRr, 2 n = 18). The backcross with oilseed rape cytoplasm (OBC) has a fitness value 100 times lower than that of the backcross with wild radish cytoplasm (RBC). The herbicide-resistant RBC has similar growth to the susceptible RBC, but final male and female fitness values are two times lower. In turn, susceptible RBC exhibit similar fitness to the control wild radishes. The relative fitnesses of the different types are the same whether or not they grow under competitive conditions. The consequence on fitness of the chromosome location of the transgene conferring resistance and the relevance of these results to the impact of gene flow on the environment are discussed.
Bernal E Valverde - One of the best experts on this subject based on the ideXlab platform.
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a strategy to provide long term control of weedy rice while mitigating herbicide resistance transgene flow and its potential use for other Crops with related weeds
Pest Management Science, 2009Co-Authors: Jonathan Gressel, Bernal E ValverdeAbstract:Transgenic herbicide-resistant rice is needed to control weeds that have evolved herbicide resistance, as well as for the weedy (feral, red) rice problem, which has been exacerbated by shifting to direct seeding throughout the world-firstly in Europe and the Americas, and now in Asia, as well as in parts of Africa. Transplanting had been the major method of weedy rice control. Experience with imidazolinone-resistant rice shows that gene flow to weedy rice is rapid, negating the utility of the technology. Transgenic technologies are available that can contain herbicide resistance within the Crop (cleistogamy, male sterility, targeting to chloroplast genome, etc.), but such technologies are leaky. Mitigation technologies tandemly couple (genetically link) the gene of choice (herbicide resistance) with mitigation genes that are neutral or good for the Crop, but render hybrids with weedy rice and their offspring unfit to compete. Mitigation genes confer traits such as non-shattering, dwarfism, no secondary dormancy and herbicide sensitivity. It is proposed to use glyphosate and glufosinate resistances separately as genes of choice, and glufosinate, glyphosate and bentazone susceptibilities as mitigating genes, with a six-season rotation where each stage kills Transgenic Crop volunteers and Transgenic Crop x weed hybrids from the previous season.
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a strategy to provide long term control of weedy rice while mitigating herbicide resistance transgene flow and its potential use for other Crops with related weeds
Pest Management Science, 2009Co-Authors: Jonathan Gressel, Bernal E ValverdeAbstract:Transgenic herbicide-resistant rice is needed to control weeds that have evolved herbicide resistance, as well as for the weedy (feral, red) rice problem, which has been exacerbated by shifting to direct seeding throughout the world—firstly in Europe and the Americas, and now in Asia, as well as in parts of Africa. Transplanting had been the major method of weedy rice control. Experience with imidazolinone-resistant rice shows that gene flow to weedy rice is rapid, negating the utility of the technology. Transgenic technologies are available that can contain herbicide resistance within the Crop (cleistogamy, male sterility, targeting to chloroplast genome, etc.), but such technologies are leaky. Mitigation technologies tandemly couple (genetically link) the gene of choice (herbicide resistance) with mitigation genes that are neutral or good for the Crop, but render hybrids with weedy rice and their offspring unfit to compete. Mitigation genes confer traits such as non-shattering, dwarfism, no secondary dormancy and herbicide sensitivity. It is proposed to use glyphosate and glufosinate resistances separately as genes of choice, and glufosinate, glyphosate and bentazone susceptibilities as mitigating genes, with a six-season rotation where each stage kills Transgenic Crop volunteers and Transgenic Crop × weed hybrids from the previous season. Copyright © 2009 Society of Chemical Industry
Charles Neal Stewart - One of the best experts on this subject based on the ideXlab platform.
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transgene excision in pollen using a codon optimized serine resolvase cinh rs2 site specific recombination system
Plant Molecular Biology, 2011Co-Authors: Hong S Moon, Laura L Abercrombie, Shigetoshi Eda, Robert Blanvillain, James G Thomson, Charles Neal StewartAbstract:Transgene escape, a major environmental and regulatory concern in Transgenic Crop cultivation, could be alleviated by removing transgenes from pollen, the most frequent vector for transgene flow. A transgene excision vector containing a codon optimized serine resolvase CinH recombinase (CinH) and its recognition sites RS2 were constructed and transformed into tobacco (Nicotiana tabacum cv. Xanthi). CinH recombinase recognized 119 bp of nucleic acid sequences, RS2, in pollen and excised the transgene flanked by the RS2 sites. In this system, the pollen-specific LAT52 promoter from tomato was employed to control the expression of CinH recombinase. Loss of expression of a green fluorescent protein (GFP) gene under the control of the LAT59 promoter from tomato was used as an indicator of transgene excision. Efficiency of transgene excision from pollen was determined by flow cytometry (FCM)-based pollen screening. While a Transgenic event in the absence of CinH recombinase contained about 70% of GFP-synthesizing pollen, three single-copy transgene events contained less than 1% of GFP-synthesizing pollen based on 30,000 pollen grains analyzed per event. This suggests that CinH-RS2 recombination system could be effectively utilized for transgene biocontainment.
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additive transgene expression and genetic introgression in multiple green fluorescent protein Transgenic Crop x weed hybrid generations
Theoretical and Applied Genetics, 2003Co-Authors: Reginald J Millwood, M D Halfhill, Arthur K Weissinger, Suzanne I Warwick, Charles Neal StewartAbstract:The level of transgene expression in Crop × weed hybrids and the degree to which Crop-specific genes are integrated into hybrid populations are important factors in assessing the potential ecological and agricultural risks of gene flow associated with genetic engineering. The average transgene zygosity and genetic structure of Transgenic hybrid populations change with the progression of generations, and the green fluorescent protein (GFP) transgene is an ideal marker to quantify transgene expression in advancing populations. The homozygous T1 single-locus insert GFP/Bacillus thuringiensis (Bt) Transgenic canola (Brassica napus, cv Westar) with two copies of the transgene fluoresced twice as much as hemizygous individuals with only one copy of the transgene. These data indicate that the expression of the GFP gene was additive, and fluorescence could be used to determine zygosity status. Several hybrid generations (BC1F1, BC2F1) were produced by backcrossing various GFP/Bt Transgenic canola (B. napus, cv Westar) and birdseed rape (Brassica rapa) hybrid generations onto B. rapa. Intercrossed generations (BC2F2 Bulk) were generated by crossing BC2F1 individuals in the presence of a pollinating insect (Musca domestica L.). The ploidy of plants in the BC2F2 Bulk hybrid generation was identical to the weedy parental species, B. rapa. AFLP analysis was used to quantify the degree of B. napus introgression into multiple backcross hybrid generations with B. rapa. The F1 hybrid generations contained 95–97% of the B. napus-specific AFLP markers, and each successive backcross generation demonstrated a reduction of markers resulting in the 15–29% presence in the BC2F2 Bulk population. Average fluorescence of each successive hybrid generation was analyzed, and homozygous canola lines and hybrid populations that contained individuals homozygous for GFP (BC2F2 Bulk) demonstrated significantly higher fluorescence than hemizygous hybrid generations (F1, BC1F1 and BC2F1). These data demonstrate that the formation of homozygous individuals within hybrid populations increases the average level of transgene expression as generations progress. This phenomenon must be considered in the development of risk-management strategies.
