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I was wondering: when a treatment modifies a group of gene (like in gene therapy), what makes a group of cell remains?
I mean, when a cell divide itself to create new ones, if a cell was initially genetically modified, it will lead to two modified one, right? But, I assume that we have a finite number of cells in our body, so if the process was going on like that, we would just have to modify one cell of our body. But, besides this, the other cells divide themselves too, so there might be something that makes a group of cell dominant (like the proportion, the number of neighbors of one cell… ).
So, my question (cut in three) is:
- What are the conditions for a group of modified cells to remain?
- In what extend the modification can spread?
- If it can't spread, why?
(I'm not a biologist student (I studied it in high school, so I may be able to understand the basics), but I'm interested in making a mathematical model of such a process. So if there is an answer, could you make it understandable for someone who has only the basis?)
Top 4 Applications of Genetic Engineering
The following points highlight the top four applications of genetic engineering. The applications are: 1. Application in Agriculture 2. Application to Medicine 3. Energy Production 4. Application to Industries.
Genetic Engineering: Application # 1. Application in Agriculture:
An important application of recombinant DNA technology is to alter the genotype of crop plants to make them more productive, nutritious, rich in proteins, disease resistant, and less fertilizer consuming. Recombinant DNA technology and tissue culture techniques can produce high yielding cereals, pulses and vegetable crops.
Some plants have been genetically programmed to yield high protein grains that could show resistance to heat, moisture and diseases.
Some plants may even develop their own fertilizers some have been genetically transformed to make their own insecticides. Through genetic engineering some varieties have been produced that could directly fix atmospheric nitrogen and thus there is no dependence on fertilizers.
Scientists have developed transgenic potato, tobacco, cotton, corn, strawberry, rape seeds that are resistant to insect pests and certain weedicides.
Bacterium, Bacillus thurenginesis produces a protein which is toxic to insects. Using the techniques of genetic engineering, the gene coding for this toxic protein called Bt gene has been isolated from bacterium and engineered into tomato and tobacco plants. Such transgenic plants showed nee to tobacco horn worms and tomato fruit worms. These genotypes are awaiting release in USA.
There are certain genetically evolved weed killers which are not specific to weeds alone but kill useful crops also. Glyphosate is a commonly used weed killer which simply inhibits a particular essential enzyme in weeds and other crop plants. A target gene of glyphosate is present in bacterium salmonella typhimurium. A mutant of S. typhimurium is resistant to glyphosate.
The mutant gene was t cloned to E. coli and then recloned to Agrobacterium tumifaciens through its Ti Plasmid. Infection of plants with Ti plasmid containing glyphosate resistant gene has yielded crops such as cotton, tabacco maize, all of which are resistant to glyphosate.
This makes possible to spray the crop fields with glyphosate which will kill the weeds only and the genetically modified crops with resistant genes remain unaffected.
Recently Calogene, a biotech company, has isolated a bacterial gene that detoxifies side effects of herbicides. Transgenic tobacco plants resistant to T MV mosaic virus and tomato i resistant to Golden mosaic virus have been developed by transferring virus coat protein genes »susceptible plants. These are yet to be released.
The gene transfer technology can also play significant role in producing new and improved variety of timber trees.
Several species of microorganisms have been produced that can degrade toxic chemicals and could be used for killing harmful pathogens and insect pests.
For using genetic engineering techniques for transfer of foreign genes into host plant cells, a number of genes have already been cloned and complete libraries of DNA and mt DNA of pea are now known.
Some of the cloned genes include:
(i) Genes for phaseolin of french bean,
(ii) Few phaseolin leg haemoglobin for soybean,
(iii) Genes for small sub-unit RUBP carboxylase of pea, and i genes for storage protein in some cereals.
Efforts are being made to improve several agricultural crops using various techniques of genetic engineering which include:
(i) Transfer of nitrogen fixing genes (nif genes) from leguminous plants into cereals.
(ii) Transfer of resistance against pathogens and pests from wild plants to crop plants.
(iii) Improvement in quality and quantity of seed proteins.
(iv) Transfer of genes for animal proteins to crop plants.
(v) Elimination of unwanted genes for susceptibility to different diseases from cytoplasmic male sterile lines in crop like maize, where cytoplasmic male sterility and susceptibility are located in mitochondrial plasmid.
(vi) Improvement of photosynthetic efficiency by reassembling nuclear and chloroplast genes and by the possible conversion of C3 plants into C4 plants.
(vii) Development of cell lines which may produce nutritious food in bioreactors.
Genetic Engineering: Application # 2. Application to Medicine:
Genetic engineering has been gaining importance over the last few years and it will become more important in the current century as genetic diseases become more prevalent and agricultural area is reduced. Genetic engineering plays significant role in the production of medicines.
Microorganisms and plant based substances are now being manipulated to produce large amount of useful drugs, vaccines, enzymes and hormones at low costs. Genetic engineering is concerned with the study (inheritance pattern of diseases in man and collection of human genes that could provide a complete map for inheritance of healthy individuals.
Gene therapy by which healthy genes can be inserted directly into a person with malfunctioning genes is perhaps the most revolutionary and most promising aspect of genetic engineering. The use of gene therapy has been approved in more than 400 clinical trials for diseases such as cystic fibres emphysema, muscular dystrophy, adenosine deaminase deficiency.
Gene therapy may someday be exploited to cure hereditary human diseases like haemophilia and cystic fibrosis which are caused by missing or defective genes. In one type of gene therapy new functional genes are inserted by genetically engineered viruses into the cells of people who are unable to produce certain hormones or proteins for normal body functions.
Introduction of new genes into an organism through recombinant DNA technology essentially alters protein makeup and finally i body characteristics.
Recombinant DNA Technology is also used in production of vaccines against diseases. A vaccine contains a form of an infectious organism that does not cause severe disease but does cause immune system of body to form protective antibodies against infective organism. Vaccines are prepared by isolating antigen or protein present on the surface of viral particles.
When a person is vaccinate against viral disease, antigens produce antibodies that acts against the viral proteins and inactivate them. With recombinant DNA technology, scientists have been able to transfer the genes for some viral sheath proteins to vaccinia virus which was used against small pox.
Vaccines produced by gene cloning are contamination free and safe because they contain only coat proteins against which antibodies are made. A few vaccines are being produced by gene cloning, e.g., vaccines against viral hepatitis influenza, herpes simplex virus, virus induced foot and mouth disease in animals.
Until recently the hormone insulin was extracted only in limited quantities from pancreas of cows and pigs. The process was not only costly but the hormone sometimes caused allergic reactions in some patients of diabetes.
The commercial production of insulin was started in 1982 through biogenetic or recombinant DNA technology and the medical use of hormone insulin was approved by food and drug administration (FDA) of USA in 1982.
The human insulin gene has been cloned in large quantities in bacterium E. coli which could be used for synthesis of insulin. Genetically engineered insulin is commercially available as humilin.
Lymphokines are proteins which regulate immune system in human body, α -Interferon is one of the examples. Interferon is used to fight viral diseases such as hepatitis, herpes, common colds as well as cancer. Such drugs can be manufactured in bacterial cell in large quantities.
Lymphokines can also be helpful for AIDS patients. Genetically engineered interleukin-II, a substance that stimulates multiplication of lymphocytes is also available and is being currently tested on AIDS patients.
A fourteen aminoacid polypeptide hormone synthesized by hypothalamus was obtained only in a small quantity from a human cadavers. Somatostatin used as a drug for certain growth related abnormalities appears to be species specific and the polypeptide obtained from other mammals has no effect on human, hence its extraction from hypothalamus of cadavers.
Genetic engineering technique has helped in chemical synthesis of gene which is joined to the pBR 322 plasmid DNA and cloned into a bacterium. The transformed bacterium is converted into somatostatin synthesising factory. ADA (adenosine deaminase) deficiency is a disease like combined immune deficiency which killed the bubble boy David in 1984.
The children with ADA deficiency die before they are two years old. Bone marrow cells of the child after removal from the body were invaded by a harmless virus into which ADA has been inserted.
Erythropoetin, a genetically engineered hormone is used to stimulate the production of red blood cells in people suffering from severe anaemia.
Production of Blood clotting factors:
Normally heart attack is caused when coronary arteries are blocked by cholesterol or blood clot. plasminogen is a substance found in blood clots. Genetically engineered tissue plasminogen activator (tPA) enzyme dissolves blood clots in people who have suffered heart attacks. The plasminogen activator protein is produced by genetech company which is so potent and specific that it may even arrest a heart attack underway.
Cancer is a dreaded disease. Antibodies cloned from a single source and targetted for a specific antigen (monoclonal antibodies) have proved very useful in cancer treatment. Monoclonal antibodies have been target with radioactive elements or cytotoxins like Ricin from castor seed to make them more deadly. Such antibodies seek cancer cells and specifically kill them with their radioactivity or toxin.
Genetic Engineering: Application # 3. Energy Production:
Recombinant DNA technology has tremendous scope in energy production. Through this technology Ii is now possible to bioengineer energy crops or biofuels that grow rapidly to yield huge biomass that used as fuel or can be processed into oils, alcohols, diesel, or other energy products.
The waste from these can be converted into methane. Genetic engineers are trying to transfer gene for cellulase to proper organisms which can be used to convert wastes like sawdust and cornstalks first to sugar and then to alcohol.
Genetic Engineering: Application # 4. Application to Industries:
Genetically designed bacteria are put into use for generating industrial chemicals. A variety of organic chemicals can be synthesised at large scale with the help of genetically engineered microorganisms. Glucose can be synthesised from sucrose with the help of enzymes obtained from genetically modified organisms.
Now-a-days with the help of genetic engineering strains of bacteria and cyanobacteria have been developed which can synthesize ammonia at large scale that can be used in manufacture of fertilisers at much cheaper costs. Microbes are being developed which will help in conversion of Cellulose to sugar and from sugar to ethanol.
Recombinant DNA technology can also be used to monitor the degradation of garbage, petroleum products, naphthalene and other industrial wastes.
For example bacterium pseudomonas fluorescens genetically altered by transfer of light producing enzyme called luciferase found in bacterium vibrio fischeri, produces light proportionate to the amount of its breaking down activity of naphthalene which provides way to monitor the efficiency of the process.
Maize and soybeans are extensively damaged by black cutworm. Pseudomonas fluorescens is found in association with maize and soybeans. Bacillus thuringiensis contain a gene pathogenic to the pest. The pest has, over the years, not only become dangerous to the crops but has developed resistance to a number of pesticides.
When the gene from B. thuringiensis (Bt) was cloned into pseudomonas fluorescence and inoculated into the soil, it was found that genetically engineered pseudomonas fluorescens could cause the death of cutworms.
Role of GMOs in environmental management
Another application of GMOs is in the management of environmental issues. For example, some bacteria can produce biodegradable plastics, and the transfer of that ability to microbes that can be easily grown in the laboratory may enable the wide-scale “greening” of the plastics industry. In the early 1990s, Zeneca, a British company, developed a microbially produced biodegradable plastic called Biopol (polyhydroxyalkanoate, or PHA). The plastic was made with the use of a GM bacterium, Ralstonia eutropha, to convert glucose and a variety of organic acids into a flexible polymer. GMOs endowed with the bacterially encoded ability to metabolize oil and heavy metals may provide efficient bioremediation strategies.
Mixing plant species is how we've gotten papayas free of viruses, corn plants that survive drought, soybeans that stand up to weed killer, potatoes that don't bruise, and crops that yield more and cost less. That's good news for our food supply and the business of farming.
Some GMOs are specially made to be packed with extra vitamins, minerals, and other health benefits. For example, Swiss researchers created a strain of "golden" rice with a lot of beta-carotene, an antioxidant good for your eyes and skin. Soybeans whose fats have been changed so they're more like olive oil can be turned into a heart-healthy replacement for oils with trans fats that's more heat-tolerant and better for cooking. And those bruise-free potatoes are supposed to cut down on cancer-causing chemicals created when spuds become french fries.
Some biotech companies are doing experiments to make meat better for us, such as boosting the amount of omega-3-fatty acids in it. These essential fats help prevent heart disease and stroke and may protect against cancer and other conditions. They may also help control lupus, eczema, and rheumatoid arthritis. But your body doesn't make them, so you have to get them from food.
As the population grows, it's going to get harder to feed everyone. The Food and Agriculture Organization of the United Nations (FAO) estimates food production will need to double in some parts of the world by 2050. GMOs are one way to make enough nutritious food available with limited land, water, and other resources.
But people worry about pollen and seeds from genetically engineered plants spreading beyond the fields where they were planted. Or what could happen if genetically modified animals mate with non-modified or wild ones.
Reap the Benefits of GMOs
Creating GMOs offers the manufacturer many benefits. Some GMOs can resist pesticides and herbicides, so they grow strong while unwanted organisms wither around them. Genetically altered species can now thrive in climates and soils once hostile to them. They can better tolerate crowding and produce more offspring.
The consumer also benefits from GMOs. Genetically altering vegetables and fruits can make them more vibrant and last longer. Scientists can fortify them with more antioxidants, minerals and vitamins. The greater yields from GMO crops allow manufacturers to lower the price of many popular food items.
- Genetic modification (GM) technology allows the transfer of genes for specific traits between species using laboratory techniques.
- GM crops were first introduced in the U.S. in the mid-1990s. Most current GM crops grown in the U.S. are engineered for insect resistance or herbicide tolerance. Corn, soybeans, and cotton are the three largest acreage GM crops.
- GM crops grown in Colorado include corn, alfalfa, sugar beet, soybeans, and canola.
- Potential future applications of the technology include nutritional enhancements, stress tolerance, disease resistance, biofuel efficiency, and remediation of polluted sites.
- GM crops are regulated at the federal level by the U.S. Department of Agriculture (USDA), the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA), each with authority to oversee specific aspects of the crops and their products.
Since GM crops were introduced in the U.S. in the mid-1990s, they have become widely adopted by growers of several largeacreage field crops. This fact sheet explains the technology for developing GM crops and describes GM crops currently on the market in the U.S.
What are GM crops?
The term genetically modified (GM), as it is commonly used, refers to the transfer of genes between organisms using a series of laboratory techniques for cloning genes, splicing DNA segments together, and inserting genes into cells. Collectively, these techniques are known as recombinant DNA technology. Other terms used for GM plants or foods derived from them are genetically modified organism (GMO), genetically engineered (GE), bioengineered, and transgenic. ‘Genetically modified’ is an imprecise term and a potentially confusing one, in that virtually everything we eat has been modified genetically through domestication from wild species and many generations of selection by humans for desirable traits. The term is used here because it is the one most widely used to indicate the use of recombinant DNA technology. According to USDA standards for organic agriculture, seeds or other substances derived through GM technology are not allowed in organic production.
Which GM crops are currently grown in the U.S.?
Although in the U.S. genetically engineered versions of 19 plant species have been approved, only eight GM crop species are grown commercially (Figure 1). Because several of them are major crops, the area planted to GM varieties is very large. Most current GM crops have been engineered for resistance to insects, tolerance to herbicides (weed control products) or both.
Figure 1. Currently grown GM crops in the U.S., traits for which they are modified, and percent of total acreage of the crop that is planted to GM varieties. IR=insect resistant, HT=herbicide tolerant, DT=drought tolerant, VR=virus resistant.
What traits have been modified in GM crops?
Insect-resistant crops contain genes from the soil bacterium Bacillus thuringiensis (Bt). The protein produced in the plant by the Bt gene is toxic to a targeted group of insects—for example European corn borer or corn rootworm—but not to mammals. The most common herbicide tolerant (HT) crops are known as Roundup Ready®, meaning they are tolerant to glyphosate (the active ingredient in Roundup® herbicide). Glyphosate inactivates a key enzyme involved in amino acid synthesis that is present in all green plants therefore, it is an effective broad spectrum herbicide against nearly all weeds. Roundup Ready® crops have been engineered to produce a resistant form of the enzyme, so they remain healthy even after being sprayed with glyphosate. Some cultivars of corn and cotton are referred to as ‘stacked’, meaning they have transgenes for both insect resistance and HT. According to USDA-ERS (2013), over half of the U.S. corn and cotton acreage was planted to stacked cultivars in 2013.
Which GM crops are grown in Colorado?
Corn, alfalfa, and sugar beet are the major GM crops grown in Colorado, but smaller areas of soybeans and canola are also planted. The corn, alfalfa, and soybean crops are nearly all used as livestock feed. Sugar beet is used to extract and purify sugar, and canola is used mostly for edible oil. All GM seeds are targeted to commercial growers no vegetable or fruit varieties for home production are GM.
What are potential GM crops of the future?
Some potential applications of GM crop technology are:
- Nutritional enhancement: Higher vitamin content more healthful fatty acid profiles
- Stress tolerance: Tolerance to high and low temperatures, salinity, and drought
- Disease resistance: For example, orange trees resistant to citrus greening disease or American chestnut trees resistant to fungal blight
- Biofuels: Plants with altered cell wall composition for more efficient conversion to ethanol
- Phytoremediation: Plants that extract and concentrate contaminants like heavy metals from polluted sites.
How are GM crops regulated in the U.S.?
Three U.S. government entities have authority to regulate GM crops: the United States Department of Agriculture (USDA), the Environmental Protection Agency (EPA), and the Food and Drug Administration (FDA). They do not, however, individually regulate all GM crops. For example, USDA is involved in approving the field release of most GM plants, but EPA is involved only in pest and pesticide resistance traits, and FDA only regulates crops destined for food, feed, or pharmaceuticals. Thus, EPA does not have authority to regulate a vitamin-enhanced tomato, and FDA would not regulate a drought tolerant turfgrass. These federal agencies review extensive information submitted by the crop developer, for example, the nature and stability of the transgene and its protein product, effects on non-target organisms in the field environment, composition of the food product, and potential for allergic reaction. If the agencies are satisfied that the proposed crop does not pose threats to the environment and does not increase risks for food or feed safety, the crop is determined to have nonregulated status, that is, it is approved for commercialization.
Are GM crops grown in other countries?
According to a recent report (James 2014), GM crops were grown in 26 other countries in 2013. The largest global acreage crops were soybean, corn, cotton, and canola, in that order. The U.S. has the greatest area of these crops, about 40% of the world total. Other large producers include Brazil, Argentina, India, and Canada.
Besides GM crops, are there other GM ingredients in our food supply?
No GM food animals have yet been approved in the U.S., although a GM salmon engineered for rapid growth is under review. GM microorganisms are used to produce rennin for production of cheese and GM yeast has been approved for winemaking .
How does GM technology differ from other plant breeding techniques?
The era of scientific crop improvement dates back to around 1900, when the impact of Gregor Mendel’s studies on trait inheritance in peas became widely recognized. Since then, a broad range of techniques has been developed to improve crop yields, quality, and resistance to disease, insects, and environmental stress. Most plant breeding programs rely on manual cross-pollination between genetically distinct plants to create new combinations of genes. The progeny plants are intensively evaluated over several generations and the best ones are selected for potential release as new varieties. An example is a tomato variety that is selected for disease resistance and tolerance to cool temperatures. Other techniques included within the conventional plant breeding toolbox are development of hybrid varieties by crossing two parental strains to produce offspring with increased vigor and induced mutations to create useful variation. GM technology is much more precise in that it transfers only the desired gene or genes to the recipient plant. Another branch of agricultural biotechnology—distinct from GM technology—involves selecting plants for DNA patterns known to be associated with favorable traits such as higher yield or disease resistance.
The shared DNA code
Most organisms store their genetic information in the form of DNA molecules in chromosomes. The sequence of chemical bases in a DNA strand encodes a specific order of amino acids, which are the building blocks of proteins. Proteins carry out many functions in cells and tissues, which together are responsible for an organism’s characteristics. Because most life forms share this same language of heredity—and due to scientific advances in molecular biology—it is now possible to transfer a gene from one species to another, for example from a bacterium to a plant, and have it function in its new host.
What is inserted into a GM plant?
The inserted DNA fragment contains one or a few genes, which contain the DNA sequence information encoding specific proteins, along with DNA segments that regulate production of the proteins. The inserted fragment also sometimes contains a marker gene to easily identify plants that have incorporated the transferred genes, also known as transgenes, into their chromosomes.
How are transgenes inserted?
There are two principal methods for transgene insertion:
Gene gun: In this method, microscopic pellets of gold or tungsten are coated with the transgene fragment and shot at high velocity into plant cells or tissues. In a small proportion of cases, the pellet will pass through the cells and the DNA fragment will remain behind and become incorporated into a plant chromosome in the cell nucleus.
Agrobacterium tumefaciens: This method utilizes a biological vector, the soil dwelling bacterium Agrobacterium tumefaciens, which in nature transfers part of its DNA into plants and causes crown gall disease. Genetic engineers have taken advantage of this DNA transfer mechanism while disarming the disease-causing properties. Plant and bacterial cells are co-cultivated in a petri dish under conditions that facilitate gene transfer. This allows incorporation of genes in a more controlled manner than with the gene gun however, it does not work equally well in all plant species.
How are whole plants obtained from plant cells or tissues?
Insertion of transgenes is generally an inefficient process, with only a few percent of plant cells or tissues successfully integrating the foreign gene. Various strategies are used to identify the small percentage of cells/tissues that have actually been transformed. The next step is to develop those cells or tissues into whole plants capable of producing seed. This is done through a process called tissue culture, that is, growing plants on agar or a similar medium in the presence of plant nutrients and hormones under controlled environmental conditions.
What happens next?
The crop developers then begin a long series of evaluations to determine that the gene has been incorporated successfully, that it is inherited in a stable and predictable manner, that the desired trait is expressed to the expected level, and that the plant does not show any negative effects. Evaluations are initially done in controlled greenhouses and growth chambers. Once sufficient seed is produced and the appropriate permission is received, experimental plants are grown in field trials. Field evaluations follow strict guidelines that include isolation from related plants to avoid cross-pollination, careful cleaning of planting and harvesting machinery, frequent monitoring of crop growth, and checking the field for two seasons after the trial for the presence of volunteer plants that have arisen from seed inadvertently left behind.
Council for Agricultural Science and Technology (CAST). 2014. The potential impacts of mandatory labeling for genetically engineered food in the United States. Issue Paper 54. CAST, Ames, Iowa. Available at www.castscience.org/file.cfm/media/products/digitalproducts/CAST_Issue_Paper_54_web_optimized_29B2AB16AD687.pdf
Federoff, N. 2004. Mendel in the Kitchen: A Scientist’s View of Genetically Modified Food. National Academies Press, Washington, D.C. Available at www.nap.edu/catalog.php?record_id=11000
James, C. 2014. ISAAA Brief 46-2013, Global Status of Commercialized Biotech/GM Crops: 2013. www.isaaa.org/resources/publications/briefs/46/default.asp
Kole, C., C.H. Michler, A.G. Abbott, and T.C. Hall. 2010. Transgenic Crop Plants. Vol. 1: Principles and Development. Springer-Verlag, Berlin, Heidelberg.
* P. Byrne, Colorado State University, professor, soil and crop sciences. 8/14
Mutations in the PAH gene cause phenylketonuria. The PAH gene provides instructions for making an enzyme called phenylalanine hydroxylase . This enzyme converts the amino acid phenylalanine to other important compounds in the body. If gene mutations reduce the activity of phenylalanine hydroxylase, phenylalanine from the diet is not processed effectively. As a result, this amino acid can build up to toxic levels in the blood and other tissues. Because nerve cells in the brain are particularly sensitive to phenylalanine levels, excessive amounts of this substance can cause brain damage.
Classic PKU, the most severe form of the disorder, occurs when phenylalanine hydroxylase activity is severely reduced or absent. People with untreated classic PKU have levels of phenylalanine high enough to cause severe brain damage and other serious health problems. Mutations in the PAH gene that allow the enzyme to retain some activity result in milder versions of this condition, such as variant PKU or non-PKU hyperphenylalaninemia.
Changes in other genes may influence the severity of PKU, but little is known about these additional genetic factors.
Learn more about the gene associated with Phenylketonuria
6. What are the implications of GM-technologies for animals?
6.1 Animal feeds frequently contain genetically modified crops and enzymes derived from genetically modified micro-organisms. There is general agreement that both modified DNA and proteins are rapidly broken down in the digestive system.
To date no negative effects on animals have been reported. It is extremely unlikely that genes may transfer from plants to disease-causing bacteria through the food chain. Nevertheless, scientists advise that genes which determine resistance to antibiotics that are critical for treating humans should not be used in genetically modified plants. More.
6.2 As of 2004, no genetically modified animals were used in commercial agriculture anywhere in the world, but several livestock and aquatic species were being studied. Genetically modified animals could have positive environmental impacts, for example through greater disease resistance and lower antibiotic usage. However, some genetic modifications could lead to more intensive livestock production and thus increased pollution. More.
Sickle cell disease affects millions of people worldwide. It is most common among people whose ancestors come from Africa Mediterranean countries such as Greece, Turkey, and Italy the Arabian Peninsula India and Spanish-speaking regions in South America, Central America, and parts of the Caribbean.
Sickle cell disease is the most common inherited blood disorder in the United States, affecting an estimated 100,000 Americans. The disease is estimated to occur in 1 in 500 African Americans and 1 in 1,000 to 1,400 Hispanic Americans.
Current crops being sold in the food market were tested and approved for consumption by the FDA. The FDA issued a statement in regards to GM safety: "We recognize and appreciate the strong interest that many consumers have in knowing whether a food was produced using bioengineering. FDA supports voluntary labeling that provides consumers with this information and has issued draft guidance to industry regarding such labeling. One of FDA's top priorities is food safety, which means ensuring that foods, whether genetically engineered or not, meet applicable requirements for safety and labeling."
The World Health Organization (WHO) and the Organization first proposed comparative approaches to safety assessments for Economic Co-operation and Development (OECD). Comparative safety assessments are meant to be a starting point for a safety assessment and not a safety assessment in itself. However, there are some studies such as Constable and colleagues that claimed a comparative safety assessment between novel foods and GM crops does not correctly describe the safety profile of GM crops. The comparative safety assessment is focused on the safety evaluation of GM crop foods – structured outline of any potential differences between novel foods and GM crops in terms of the safety implications through appropriate methods and approaches as outlined by the OECD.
Traditional foods are inherently noted as safe due to a long history of consumption as opposed to systematic toxicological and nutritional assessment. The disconnect between comparative safety assessments and the safety of traditional foods create a false/imprecise checklist of criteria to determine whether GM crops are safe or harmful. It is important to note that the history of safe use is largely determined by the context of its traditional use, population consuming the food product and ways the traditional foods are prepared and processed. Conducting a comparative safety assessment is more of a benchmark location as to where GM crops' safety is relative to the perceived safety of traditional foods. Make this paragraph briefer and more concise
Important information in regards to both traditional and GM crops to conduct a comparative safety assessment include (Constable et al., 2007):
- Toxiocology data including details of known natural toxicants
- Nutritional data including details of known natural antinutritional factors
- Pathogenicity (for micro-organisms)
- Known health compromising contaminants (nature and level of)
- Bioactive substances
- Metabolic and/or gastrointestinal effects in humans
There are detailed guidelines for the preparation and presentation of application for approval for human consumption of GMO crops. The approval process of GMO crops into mainstream consumption requires a number of testing and the ability to pass multiple criteria to ensure safety. A history of safe use is needed to determine the regulatory status of a food, whether it is appropriate to conduct research and/or evaluate the safety of a food. The assessment, as a whole, will then be reviewed to determine the safety of GM crops for human consumption.
Below are the criteria to determine a history of safe use taken from Constable et al. 2007.
History of Safe Use - Key Issues
- Correct identification
- Biology (origin, genetic diversity)
- Length of use
- Geographic/demographic distribution of use
- Details of use
- Evidence of adverse effects
- Reliability of data
- Composition (especially toxic, allergenic, metabolic, nutritional and antinutritional components as well as health compromising compounds)
- In silico tests (e.g. structural homology to known allergens of known toxins)
- In vitro tests (e.g. serum screening, digestibility tests)
- Animal studies (toxiocology and nutritional studies)
- Clinical studies
- Epidemiological evidence
- Type/purpose (e.g. as a food, ingredient, supplement or pharmaceutical)
- Preparation and processing
- Known precautions
- Pattern of consumption (occasional, regular or co-administration)
- Intake (level, populations exposed, mean/extremes)
Need to organize this pageand incorporate some citations into sections throughout the module