Genetic Modification Advisory Committee
- established in Singapore in April 1999
- oversee and advise on the research and development, production, use and handling of Genetically Modified Organisms (GMOs) in Singapore.
- to ensure public safety while allowing for the commercial use of GMOs and GMO-derived products by companies and research institutions, in compliance with international standards.
Singapore Guidelines for GMOs
1) Questionnaire for Risk Assessment
2) Risk Assessment Criteria
3) Flowchart for Evaluation, Approval & Registration
Adapted & can be found in detail from
www.gmac.gov.sg> Home> Guidelines> Agriculture Products> Biosafety Guidelines
Monday, July 30
Various Detection Methods
Chromatography
TLC Analysis
As the chemicals being separated may be colorless, several methods exist to visualize the spots.
Often a small amount of a fluorescent compound, usually Manganese-activated Zinc Silicate, is added to the adsorbent that allows the visualization of spots under a blacklight (UV254).
The adsorbent layer will thus fluoresce light green by itself, but spots of analyte quench this fluorescence. Iodine vapors are a general unspecific color reagent Specific color reagents exist into which the TLC plate is dipped or which are sprayed onto the plate.
Once visible, the Rf value of each spot can be determined by dividing the distance traveled by the product by the total distance traveled by the solvent (the solvent front). These values depend on the solvent used, and the type of TLC plate, and are not physical constants.
Gas-Liquid Chromatography
Gas-liquid chromatography (GLC), or simply gas chromatography (GC), is a type of chromatography in which the mobile phase is a carrier gas, usually an inert gas such as helium or an unreactive gas such as nitrogen, and the stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside glass or metal tubing, called a column.
The instrument used to perform gas chromatographic separations is called a gas chromatograph (also: aerograph, gas separator).
Spectroscopy
Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. Spectroscopy is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from or absorbed by them.
Atomic Absorption Spectroscopy
Atomic absorption spectroscopy is a technique for determining the concentration of a particular metal element in a sample. Atomic absorption spectroscopy can be used to analyse the concentration of over 62 different metals in a solution.
Three steps are involved in turning a liquid sample into an atomic gas:
Desolvation – the liquid solvent is evaporated, and the dry sample remains
Vaporisation – the solid sample vaporises to a gas
Volatilisation – the compounds making up the sample are broken into free atoms
A beam of light passes through this flame at its longest axis (the lateral axis) and hits a detector.
The light that is focused into the flame is produced by a hollow cathode lamp. Inside the lamp is a cylindrical metal cathode containing the metal for excitation, and an anode.
When a high voltage is applied across the anode and cathode, the metal atoms in the cathode are excited into producing light with a certain emission spectra. This amount of energy is specific to a particular electron transition in a particular element.
As the quantity of energy put into the flame is known, and the quantity remaining at the other side (at the detector) can be measured, it is possible to calculate how many of these transitions took place, and thus get a signal that is proportional to the concentration of the element being measured.
DNA & protein eletrophoresis
Gel electrophoresis is the separation of deoxyribonucleic acid, ribonucleic acid, and protein through an electric charge. It is usually performed for analytical purposes, but may be used as a preparative technique to partially purify molecules prior to use of other methods such as mass spectrometry, PCR, cloning, DNA sequencing, or immuno-blotting for further characterization.
"Electrophoresis", refers to the electromotive force (EMF) that is used to push or pull the molecules through the gel matrix; by placing the molecules in wells in the gel and applying an electric current, the molecules will move through the matrix at different rates, towards the anode if negatively charged or towards the cathode if positively charged.
After the electrophoresis runs, when the smallest molecules have almost reached the anode, the molecules in the gel can be stained to make them visible. Ethidium bromide, silver, or coomassie blue dye can be used. Other methods can also be used to visualize the separation of the mixture's components on the gel. If the analyte molecules fluoresce under ultraviolet light, a photograph can be taken of the gel under ultraviolet light. If the molecules to be separated contain radioactive atoms, an autoradiogram can be recorded of the gel.
Thin-Layer Chromatography
TLC is a widely-used chromatography technique used to separate chemical compounds. It involves a stationary phase consisting of a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose immobilised onto a flat, inert carrier sheet.
A liquid phase consisting of the solution to be separated dissolved in an appropriate solvent is drawn through the plate via capillary action, separating the experimental solution.
It can be used to determine the pigments a plant contains, to detect pesticides or insecticides in food, in forensics to analyze the dye composition of fibers, or to identify compounds present in a given substance, among other uses. It is a quick, generic method for organic reaction monitoring.
TLC Analysis
As the chemicals being separated may be colorless, several methods exist to visualize the spots.
Often a small amount of a fluorescent compound, usually Manganese-activated Zinc Silicate, is added to the adsorbent that allows the visualization of spots under a blacklight (UV254).
The adsorbent layer will thus fluoresce light green by itself, but spots of analyte quench this fluorescence. Iodine vapors are a general unspecific color reagent Specific color reagents exist into which the TLC plate is dipped or which are sprayed onto the plate.
Once visible, the Rf value of each spot can be determined by dividing the distance traveled by the product by the total distance traveled by the solvent (the solvent front). These values depend on the solvent used, and the type of TLC plate, and are not physical constants.
Gas-Liquid Chromatography
Gas-liquid chromatography (GLC), or simply gas chromatography (GC), is a type of chromatography in which the mobile phase is a carrier gas, usually an inert gas such as helium or an unreactive gas such as nitrogen, and the stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside glass or metal tubing, called a column.
The instrument used to perform gas chromatographic separations is called a gas chromatograph (also: aerograph, gas separator).
Spectroscopy
Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. Spectroscopy is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from or absorbed by them.
Atomic Absorption Spectroscopy
Atomic absorption spectroscopy is a technique for determining the concentration of a particular metal element in a sample. Atomic absorption spectroscopy can be used to analyse the concentration of over 62 different metals in a solution.
Three steps are involved in turning a liquid sample into an atomic gas:
Desolvation – the liquid solvent is evaporated, and the dry sample remains
Vaporisation – the solid sample vaporises to a gas
Volatilisation – the compounds making up the sample are broken into free atoms
A beam of light passes through this flame at its longest axis (the lateral axis) and hits a detector.
The light that is focused into the flame is produced by a hollow cathode lamp. Inside the lamp is a cylindrical metal cathode containing the metal for excitation, and an anode.
When a high voltage is applied across the anode and cathode, the metal atoms in the cathode are excited into producing light with a certain emission spectra. This amount of energy is specific to a particular electron transition in a particular element.
As the quantity of energy put into the flame is known, and the quantity remaining at the other side (at the detector) can be measured, it is possible to calculate how many of these transitions took place, and thus get a signal that is proportional to the concentration of the element being measured.
DNA & protein eletrophoresis
Gel electrophoresis is the separation of deoxyribonucleic acid, ribonucleic acid, and protein through an electric charge. It is usually performed for analytical purposes, but may be used as a preparative technique to partially purify molecules prior to use of other methods such as mass spectrometry, PCR, cloning, DNA sequencing, or immuno-blotting for further characterization.
"Electrophoresis", refers to the electromotive force (EMF) that is used to push or pull the molecules through the gel matrix; by placing the molecules in wells in the gel and applying an electric current, the molecules will move through the matrix at different rates, towards the anode if negatively charged or towards the cathode if positively charged.
After the electrophoresis runs, when the smallest molecules have almost reached the anode, the molecules in the gel can be stained to make them visible. Ethidium bromide, silver, or coomassie blue dye can be used. Other methods can also be used to visualize the separation of the mixture's components on the gel. If the analyte molecules fluoresce under ultraviolet light, a photograph can be taken of the gel under ultraviolet light. If the molecules to be separated contain radioactive atoms, an autoradiogram can be recorded of the gel.
Mini Summary over GM debates
So far....
Health concerns:
- allergenicity
- eating foreign DNA
- unknown effects on health
- changed nutrient levels
- horizontal transfer & antibiotic resistance
Economic concerns
- GM food would result in unequal distribution of wealth as the rich who could afford GM crops would earn more and the poor would become poorer as a result
Concerns on the damage to the environment:
- Unintended harm to other organisms (plants, insects, birds and soil organisms)
- Leakage of GM proteins into soil
- Crop-to-weed gene flow
- Antibiotic resistance reduced effectiveness of pesticides
- Crop-to-crop gene transfer
- Resistance
- RecombinationLoss of biodiversity
There is some evidence for positive impacts of the planting of GM crops on reduced greenhouse gas emissions and pesticide loads in the environment. However, there has been controversy over the impact of GM crops and conventional crops on farmland biodiversity.
The benefits:
1) Better resistance for pests, disease & weather thus increased yields = enhanced food security
2) Shortened maturation time allows more crops to be grown annually = better income
3) Reduced need for chemical pesticides
4) Reduced nutrient deficiencies in under-developed countries
Other Considerations>
Social & moral concerns:
- Tampering with nature by mixing genes among species
- Important distinctions between species blurred
- Objections to consuming animal genes in plants and vice versa
- New advances may be skewed to interests of rich countries
Product Labeling is important for consumers to make informed choices
Consumers are concerned with the integrity of genetic modification. Alterations in genes refer to an item that is unnatural hence consumers are apprehensive towards this biotechnology. People especially with pious religion values and beliefs therefore find GE unacceptable.
Many people feel that gene transplantation processes to the germ plasm of crops violates the natural order. Religion devotees fear that genes for the GM food might be isolated or derived from abstained animals.
Health concerns:
- allergenicity
- eating foreign DNA
- unknown effects on health
- changed nutrient levels
- horizontal transfer & antibiotic resistance
Economic concerns
- GM food would result in unequal distribution of wealth as the rich who could afford GM crops would earn more and the poor would become poorer as a result
Concerns on the damage to the environment:
- Unintended harm to other organisms (plants, insects, birds and soil organisms)
- Leakage of GM proteins into soil
- Crop-to-weed gene flow
- Antibiotic resistance reduced effectiveness of pesticides
- Crop-to-crop gene transfer
- Resistance
- RecombinationLoss of biodiversity
There is some evidence for positive impacts of the planting of GM crops on reduced greenhouse gas emissions and pesticide loads in the environment. However, there has been controversy over the impact of GM crops and conventional crops on farmland biodiversity.
The benefits:
1) Better resistance for pests, disease & weather thus increased yields = enhanced food security
2) Shortened maturation time allows more crops to be grown annually = better income
3) Reduced need for chemical pesticides
4) Reduced nutrient deficiencies in under-developed countries
Other Considerations>
Social & moral concerns:
- Tampering with nature by mixing genes among species
- Important distinctions between species blurred
- Objections to consuming animal genes in plants and vice versa
- New advances may be skewed to interests of rich countries
Product Labeling is important for consumers to make informed choices
Consumers are concerned with the integrity of genetic modification. Alterations in genes refer to an item that is unnatural hence consumers are apprehensive towards this biotechnology. People especially with pious religion values and beliefs therefore find GE unacceptable.
Many people feel that gene transplantation processes to the germ plasm of crops violates the natural order. Religion devotees fear that genes for the GM food might be isolated or derived from abstained animals.
What is Genetic Engineering?
Definition:
Genetic Engineering is the use of various methods to manipulate the DNAof cells to change hereditary traits or produce biological products. It involve gene splicing or recombinant DNA, in whihc the DNA of a desired gene is inserted into the DNA of a bacterium,which then reproduces itself yielding more of the desired gene.
Genetic Engineering Techniques
Genetic Engineering is the use of various methods to manipulate the DNAof cells to change hereditary traits or produce biological products. It involve gene splicing or recombinant DNA, in whihc the DNA of a desired gene is inserted into the DNA of a bacterium,which then reproduces itself yielding more of the desired gene.
Genetic Engineering Techniques
1) Recombinant DNA
- the common technique that relies on biological vectors like plasmids & vectors
2) Microinjection
- simply injecting the genetic materialof the new gene into the recipient cell
3) Electro- and Chemical Poration
- involves creating pores or holes int he cell membrane to allow entry of the new genes
4) Bioballistics
- projectile method that uses metal silvers to deliver the genetic material to the interior of the cell
Purposes of Genetic Modification- Improve & extend shelf life of crops
- Improve nutritional value
- Improved farmer's crop yield
- Pest resistance
- Herbicide resistance
- Pharmaceutical benefits
Risks of Genetic Engineering
>>> Potential Harm to Health
- Transferring of gene, could bring about new allergens in food supply
- The presence of antibiotic-resistance genes could be harmful in the long run
- Addition of new genetic material can activate the inactive pathways in the organism hence indirectly causing the production of new toxins
>>> Potential Environmental Harm
- Increased weediness; Weeds are plants that grow unaided by humans in places where they have unwanted effects. A new combination of traits might enable crops to thrive unaided in the environment in circumstances where they would then be considered new or worse weeds WHICH COULD SEVERELY INHIBIT CROP YIELD..
- Cross pollination to wild or weedy relatives could intensify the weedy properties.
- Certain Genetically engineered crops like Bt crops; pest constantly exposed to it could develop a resistance and will render the Bt pesticide useless..
- One of the most common application of genetic engineering is the production of virus-tolerant crops. The plants producing viral components on their own are resistant to subsequent infection by those viruses. Such plants, however, pose other risks of creating new or worse viruses through two mechanisms: recombination and transcapsidation.
GM food safety issues
Toxic GM Potatoes
In August 1998 widespread concern, especially in Europe, was sparked by remarks by nutrition researcher, regarding some of his research into the safety of GM foods.
Pusztai claimed his experiments showed that rats fed on potatoes genetically engineered to express a lectin from snowdrop had suffered serious damage to their immune systems and shown stunted growth. The lectin expressed by the genetically modified potatoes is toxic to insects and nematodes and is allegedly toxic to mammals. He was criticized by leading British politicians, the majority of scientific peers with expertise in the area and by the GM companies because the announcement of his results in a television interview, preceded the scientific publication of his results. When his studies were finally published in The Lancet, no evidence of stunted growth or damage to immune system was substantiated.
GM Corn
Another controversy recently arose around biotech company Monsanto's data on a 90-Day Rat Feeding Study on the MON863 strain of GM corn. In May 2005, critics of GM foods pointed to differences in kidney size and blood composition found in this study, suggesting that the observed differences raises questions about the regulatory concept of substantial equivalence.
The raising of this issue prompted the European Food Safety Authority (EFSA) to reexamine the saftey data on this strain of Corn. The EFSA concluded that the observed small numerical decrease in rat kidney weights were not biologically meaningful, and the weights were well within the normal range of kidney weights for control animals. There were no corresponding microscopic findings in the relevant organ systems, and all blood chemistry and organ weight values fell within the "normal range of historical control values" for rats.
GM soybean (Brazil-nut allergy)
A gene for an allergenic trait has been transferred unintentionally from the Brazil nut into genetically engineered soybeans while intending to improve soybean nutritional quality for animal feed use. Brazil nuts were already known to produce food allergies in certain people prior to this study. In 1993 Pioneer Hi-Bred International developed a soybean variety with an added gene from the Brazil nut. This trait increased the levels in the GM soybean of the natural essential amino acid methionine, a protein building block commonly added to poultry feed to improve effective protein quality. Investigation of the GM soybeans revealed that they produced immunological reactions with people suffering from Brazil nut allergy, and the explanation for this is that the methionine rich protein chosen by Pioneer Hi-Bred is the major source of Brazil nut allergy
What is wrong with Genetic Modification?
1) Crops which have been Genetically Modified to resist herbicides encourage the use of larger quantities of herbicide, with the effect that both weeds and beneficial plants are killed indiscriminately. These herbicides are harmful to both the environment and to humans.
2) Crops which have been Genetically Modified to contain their own insecticide, such as Bt, cause insects to become resistant to the insecticide.
3) Genetically Modified plants may crossbreed with wild species to produce "superweeds", which cannot be eliminated using standard herbicides.
4) The use of Genetically Modified seed encourages dependence by the farmers on a single seed supplier and may involve the purchase of both the seed and herbicide from one supplier. Seed companies impose 'licensing agreements' for the seed which forbid the farmer from replanting seed from one year to the next.
5) Toxic compounds such as glyphosate (RoundUp) and Bromoxynil are used on Genetically Modified crops.
6) The nature of genetic modification and long term effects are not well understood as these products have not been properly tested before being released into the environment.
7) Genetic material inserted into plants can transfer to animals and humans in the intestinal wall.
8) Crops which have been Genetically Modified to resist insects kill not just the "target insect" (such as the borer or weevil) but beneficial insects (such as the Monarch butterfly). They also threaten the habitats of other animals, such as birds.
9) Crops which have been Genetically Modified to produce pharmaceuticals can contaminate the food supply.
In August 1998 widespread concern, especially in Europe, was sparked by remarks by nutrition researcher, regarding some of his research into the safety of GM foods.
Pusztai claimed his experiments showed that rats fed on potatoes genetically engineered to express a lectin from snowdrop had suffered serious damage to their immune systems and shown stunted growth. The lectin expressed by the genetically modified potatoes is toxic to insects and nematodes and is allegedly toxic to mammals. He was criticized by leading British politicians, the majority of scientific peers with expertise in the area and by the GM companies because the announcement of his results in a television interview, preceded the scientific publication of his results. When his studies were finally published in The Lancet, no evidence of stunted growth or damage to immune system was substantiated.
GM Corn
Another controversy recently arose around biotech company Monsanto's data on a 90-Day Rat Feeding Study on the MON863 strain of GM corn. In May 2005, critics of GM foods pointed to differences in kidney size and blood composition found in this study, suggesting that the observed differences raises questions about the regulatory concept of substantial equivalence.
The raising of this issue prompted the European Food Safety Authority (EFSA) to reexamine the saftey data on this strain of Corn. The EFSA concluded that the observed small numerical decrease in rat kidney weights were not biologically meaningful, and the weights were well within the normal range of kidney weights for control animals. There were no corresponding microscopic findings in the relevant organ systems, and all blood chemistry and organ weight values fell within the "normal range of historical control values" for rats.
GM soybean (Brazil-nut allergy)
A gene for an allergenic trait has been transferred unintentionally from the Brazil nut into genetically engineered soybeans while intending to improve soybean nutritional quality for animal feed use. Brazil nuts were already known to produce food allergies in certain people prior to this study. In 1993 Pioneer Hi-Bred International developed a soybean variety with an added gene from the Brazil nut. This trait increased the levels in the GM soybean of the natural essential amino acid methionine, a protein building block commonly added to poultry feed to improve effective protein quality. Investigation of the GM soybeans revealed that they produced immunological reactions with people suffering from Brazil nut allergy, and the explanation for this is that the methionine rich protein chosen by Pioneer Hi-Bred is the major source of Brazil nut allergy
What is wrong with Genetic Modification?
1) Crops which have been Genetically Modified to resist herbicides encourage the use of larger quantities of herbicide, with the effect that both weeds and beneficial plants are killed indiscriminately. These herbicides are harmful to both the environment and to humans.
2) Crops which have been Genetically Modified to contain their own insecticide, such as Bt, cause insects to become resistant to the insecticide.
3) Genetically Modified plants may crossbreed with wild species to produce "superweeds", which cannot be eliminated using standard herbicides.
4) The use of Genetically Modified seed encourages dependence by the farmers on a single seed supplier and may involve the purchase of both the seed and herbicide from one supplier. Seed companies impose 'licensing agreements' for the seed which forbid the farmer from replanting seed from one year to the next.
5) Toxic compounds such as glyphosate (RoundUp) and Bromoxynil are used on Genetically Modified crops.
6) The nature of genetic modification and long term effects are not well understood as these products have not been properly tested before being released into the environment.
7) Genetic material inserted into plants can transfer to animals and humans in the intestinal wall.
8) Crops which have been Genetically Modified to resist insects kill not just the "target insect" (such as the borer or weevil) but beneficial insects (such as the Monarch butterfly). They also threaten the habitats of other animals, such as birds.
9) Crops which have been Genetically Modified to produce pharmaceuticals can contaminate the food supply.
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