ISSUES AND ETHICS SURROUNDING GENETIC ENGINEERING OF FOODS

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1 ISSUES AND ETHICS SURROUNDING GENETIC ENGINEERING OF FOODS BACKGROUND This activity is aimed at increasing student awareness of the issues surrounding the development of biotechnology and the products of genetic engineering, especially in the area of food. Within the next few years literally thousands of genetically modified food products or products with genetically modified components could be put onto the world market. The incentive for pursuing this area of biotechnology comes in four main categories: better health, better products, better for the environment, and better business. There are a number of practical and ethical implications associated with this technology which are not readily understood by the public and often become emotive when publicised through the news media. It is important for people to be able to knowledgeably discuss the possible benefits and costs of this technology along with some of the ethical concerns as public debate heightens in the future. WHAT IS GENETIC ENGINEERING? The process of genetic engineering is known by many different names such as gene, or DNA manipulation, gene splicing, transgenics and many others. However the underlying processes all have the same aim and that is: To isolate single genes of a known function from one organism and transfer a copy of that gene to a new host to introduce a desirable characteristic The structure of every living thing is determined by its genes. A gene is a chemical code which contains an instruction for the body to express a particular attribute such as eye colour, skin pigment or height. Each gene is made up of a segment of DNA (deoxyribonucleic acid). Scientists are able to extract DNA from any organism and can then isolate a specific gene through the use of restriction endonucleases, which cut DNA strands at specific points. The gene is then copied billions fold in readiness for transfer to another organism. METHODS OF GENE TRANSFER There are four primary methods of introducing an isolated gene into the host. These are: 1. Injection. This is used primarily in animals. The new DNA is injected with a very small sharp needle into the nucleus of a single cell. This cell is usually a fertilised egg which can then be placed back in the female uterus where the injected cell is allowed to develop

2 normally. Unfortunately there is a high rate of failure when using this technique as cells infrequently take up and express the desired traits of the introduced DNA. 2. Biolistics. Biolistics is used in the genetic modification of plants and involves shooting new genes into the potential host. Microscopic particles of gold or titanium are coated in the DNA sections which are to be introduced to the host. These are loaded into cartridges, similar to shotgun cartridges, which are then fired at the plant cells. The processrelies on some of the microscopic particles entering this cell nuclei and their DNA coating combining with the plant chromosomes. 3. Vectors. This method has the potential to be used in both plant and animal situations. It involves a bacteria or virus carrying a new gene into a cell. Using a modification of what is already happening in nature. Common vectors in gene transfer between plants are Agrobacterium tumefaciens and Agrobacterium rhizogenes. These bacteria are usually found in the soil and if they infect plants will respectively cause galls or hairy roots through introducing some of their own DNA into the plant. The Agrobacterium transfer the DNA as a plasmid, a small circular piece of DNA, which is separate to the main bacterial chromosome. Genetic engineering makes use of this natural transfer of DNA through replacing a section of the bacteria s own DNA with a gene which scientists would like to introduce to a new host. 4. Protoplast transformation. This is also commonly used in plants. The cellulose in the plant wall is dissolved away using enzymes leaving a protoplast. DNA can then be added to the protoplast which are then cultured on a growth media. This encourages the protoplast to regrow cell walls and eventually grow into a transgenic plant. MARKER GENES When making genetic modifications it is important that the scientist is able to tell if the transformation has been successful. For this reason it is usual to introduce a marker gene to the host so that successful transformations of DNA can be identified. For example in plant transgenics, a gene which confers resistance to the antibiotic kanamycin is often used. The desired gene is transferred along with the kanamycin resistant gene attached. Following this process, the potentially transformed cells are placed in a growth medium containing kanamycin. Those cells which have been transformed (now containing a

3 kanamycin resistance gene) will grow in the media while the other unaltered cells will die. POTENTIAL BENEFITS OF GENE TECHNOLOGY As previously mentioned the incentives for modifying organisms and especially food genetically, come in four main categories: better health, better products and better for the environment. Better Health Genetically modified food has great potential as a relatively cheap source of human therapeutics, especially for the worlds poorer countries. In 1996 US researchers were genetically engineering a banana to produce an antigen found in the outer coat of the hepatitis B virus. If successful this banana could immunise children in developing countries for just a few cents per dose. Currently traditional hepatitis B vaccines cost between $100 and $200 per dose. Researchers say that a banana or any fruit that is eaten raw could be genetically engineered to vaccinate against a wide range of diseases, providing a cheap source of protection. Food is also being modified to increase its nutritional value through altering the vitamin, mineral, carbohydrate, protein and fat profiles. Better Products Aside from health benefits, food can be improved through making the process of producing them easier for the farmer or grower. This improvement comes about through providing the plant with pest and disease resistance or increasing crop tolerance to a wider range of climates, or making the food more attractive to the consumer. Crops are difficult to raise for different reasons, for example strawberries are not very frost hardy which makes them difficult to grow in certain climates. However a few years ago researchers discovered that the Arctic flounder produces an anti freeze to protect itself in Arctic waters. Research is now underway to introduce the anti freeze gene into fruits and vegetables like strawberries and soya beans which can be damaged or destroyed by frost. In the same way a gene from the common soil bacterium Bacillus thuringiensis or Bt for short, which is well known for its insecticidal properties can be incorporated into crops to make them more resistant to an insect attack. From the consumers point of view food can be made more attractive in many ways. Possible examples include apples which don t go brown after a few minutes when you cut or bite into them, or onions that don t make your eyes water. Genetic engineering has also provided the possibility of raising crops with less use of chemical protectants such as herbicides and fungicides. This means less residue on the crops which is also makes this type of product more attractive to the consumer.

4 Better For The Environment Growing genetically modified crops resistant to pests or diseases could reduce the eliance of agriculture on chemical sprays. While this makes the crop easier and cheaper to grow for the farmer, it also means that other indirect costs of spraying are eliminated, eg. knocking out all the beneficial insects and vertebrates through the use of chemical pesticides. Such resistance provides a good marketing opportunity whereby Canada may be able to enhance its clean green image. The development of herbicide resistant crops generally involves transferring genes with resistance to environmentally friendly herbicides such as Glyphosate (Round Up). This allows growers to spray such herbicides without damaging the crop plant. Effects On People Nutritional value of food Genetically modifying foods can alter their nutritional value. This can have undesirable as well as beneficial effects. For example, researchers recently inserted a gene from a Brazil nut into soybean to try and improve its nutritional quality. However, in their testing, they found that the protein produced was the one responsible for the allergenicity of Brazil nuts. This allergenicity was also transferred to the soybeans. As a consequence, this soybean has never been marketed. The nutritional value of food could also be diminished by inserted genes interrupting the function of other genes in a genetically modified plant. However, these should normally be detected during the experimental stage and/or testing. Effects of marker genes During genetic transformation not all cells will undergo the desired modification and it is therefore necessary to select those that have been changed. To do this a marker gene may be inserted along with the desired gene into the plant. As previously mentioned a marker gene may confer resistance to specific antibiotics so that when these antibiotics are added to the growth medium, only those cells with the desired modification will grow. Some people worry that live GMF s could transfer antibiotic resistant genes to people. While it is highly unlikely, if it did occur this could have negative effects on the efficiency of some antibiotics currently in use by medical practitioners and limit the number of antibiotics available. To counteract this, regulatory authorities advise that, wherever GMF s are to be consumed live, such as is the case with live yoghurt made using modified starter cultures, the marker genes should be eliminated from the final product. This is only a problem with raw products as DNA, including the antibiotic resistant gene, is altered by the cooking process. There is no public benefit from having antibiotic genes or proteins in GMF. Ethical considerations Given genes can be transferred from any organism to another, some ethical considerations arise. For example when eating a vegetable will a vegetarian be concerned to learn that their broccoli contains DNA copied from a pig gene? If it were to contain

5 copies of a human gene does this mean that the person eating it is a cannibal? While people will be put off or even outraged by such possibilities, technologists point out that although there may be an ethical dilemma which is likely to be debated emotively, the chemical structure of DNA is the same whether you are a human, a tree or an amoeba. It is only the sequence of the nucleotides within the DNA which determines the genetic makeup of the organism. Effects In Agriculture Use of herbicides and pesticide resistant genes Tolerance of crops to herbicides, insects and pests and adverse climatic conditions are the most hotly researched characteristics of crops at present. However potential dangers are seen in a number of areas. 1. Pests and diseases can develop tolerance to the genetically conferred pest and disease resistance factors in the crop as a result of high selection pressure. This may mean that resistance quickly becomes obsolete and other methods may be required to control the pest or disease. Plant breeders point out that these types of selection pressures are already exerted through the use of traditional techniques. Insect and disease resistance in crops has changed regularly over the past 100 years without the creation of a super bug which is resistant to all controls. 2. The genetically modified crop may interbreed with closely related weed type species, thus making these weeds difficult to control with some specific herbicides. 3. It is also thought that the genetically modified crop itself may become a weed in its own right due to its resistance to chemicals and potentially wide range of climate tolerance if it was allowed to escape the confines of the paddock. Where possible biologists are endeavouring to make such crops sterile so the risk of crossing with other species is minimised. Displacement of indigenous flora and fauna Any new organisms may be more competitive than native flora and fauna in the native species own ecological niche. Examples of potential devastation can be seen in the introduction of gorse, rabbits, stoats, possums and even domestic cats which were introduced without full understanding of the impact their release would have on native ecosystems. It is everybody s responsibility to ensure native flora and fauna are sustained for future generations. Disturbance of natural selection A commonly voiced concern in the general community is: Does man have the right to play God? Natural selection also selects over a very long period of time. Whereas

6 genetic modification can make large changes quickly. Biologists point out that through the use of traditional breeding technologies man has been playing God in the same way for hundreds of years. Long term risks Long term consequences cannot be completely predicted. While risk assessment can be a relatively comprehensive process, commercial needs also push towards GMO s available being released as quickly as possible. Opponents of gene modification point to the example of nuclear technology as reasons to leave gene technology alone. Nuclear technology has had some ghastly health consequences for those working with it, with problems ranging from development of cancer to birth defects. Those problems arose due to a lack of knowledge at the time of the long term effects these technologies could have on the people and the environment. BIODIVERSITY Biodiversity is vital as it represents the genetic pool that will enable living things to cope with future change Opponents of biotechnology commonly promote the theory that the use of genetic modification technologies will lead to a decrease in biodiversity thus reducing the sustainability of the planet. Initially this is incorrect as inserting a new gene into an existing genome can be regarded as increasing biodiversity. However, if such a change is proved superior to the parent plant, adoption of the new strain may lead to one or more older plants not being grown any more and this does reduce biodiversity and possibly sustainability. During the 1950 s and 60 s famine was common in India and China. However, with development of new varieties of wheat and rice in the Green Revolution India and China are now self sufficient in these staple crops. The Green Revolution was brought about by the use of traditional breeding to reduce stem length (which later proved to be controlled by a single gene) in wheat and rice. The new varieties gave very high yields when fertiliser was used without lodging (falling over) and consequent losses of grain. The new cultivars were so superior farmers stopped growing any traditional varieties which leads to a decrease in biodiversity. As a result the FAO has established the International Plant Genetic Resource Institute to conserve such obsolete cultivars and maintain the potential biodiversity of the planet.

7 Questions: 1. In your own words, what is genetic engineering? 2. Define the term vector. How is a vector used to make a gene transfer? 3. What is a marker gene and why is it introduced during gene transfers? 4. How might the insertion of a marker gene such as antibiotic resistance be a problem? 5. How does inserting a gene that codes for a specific antigen (like the hepatitis B virus) impart immunity to this disease? 6. Describe two ways that use of genetic engineering used with crops can improve crop yields or quality. 7. How does DNA differ from one organism to another? 8. What is selection pressure and how does it allow a pest to become resistant to a measure used to control it? 9. How might an introduced species be detrimental to native species in an area? 10. Explain how a decrease in biodiversity could reduce the sustainability of the planet.