5. Important Public Concerns Related to the Application of Biotechnology

Public concerns related to the application of biotechnology focus primarily on genetic engineering, gene cloning and DNA manipulation. It perhaps is unfortunate that these are the terms generally used to refer to “in vitro recombinant DNA techniques” since they have connotations of interfering with the natural processes of reproduction, heredity and growth and even initially raised visions of Aldous Huxley’s Brave New World and the spectre of eugenics.

Eurobarometer surveys conducted since 1973, on behalf of the EU Directorate General for Education and Culture, have highlighted a growing public concern about the applications of biotechnology. Concerns expressed by the general public relate particularly to the use of recombinant DNA techniques. By comparison with the 1996 Eurobarometer survey, the perception of the utility and the moral acceptability of four selected biotechnology applications (introducing human genes into bacteria to produce medicines and vaccines, developing transgenic plants, using genetic testing and producing genetically modified food) had decreased considerably in the 1999 survey¹⁶. While considerable anxiety was felt by consumers regarding the placing of genetically-modified foods on the market, the same individuals responded much more favourably to the use of genetic engineering techniques for developing new drugs and medicines.

Most controversy in the media relates to the production of genetically modified crops and the marketing of foods derived from these crops. Consumers have expressed concerns about toxicity, allergenicity and other unforeseen long-term adverse effects. There is also concern about the regulations governing labelling of GM foods, abuse of labelling regulations, and the guarantee of consumer choice.

Wider issues of public concern regarding the application of recombinant DNA technology include:

• ethical/moral arguments regarding the development of transgenic species –i.e. is the transfer of a gene from an animal to a crop or microbial species an acceptable interference with nature?
• environmental considerations such as, for example, the potential spread of introduced genes from a GM plant to other plant species
• the potential human health impact of introducing antibiotic resistance genes to GM plants
• reduction of biodiversity
• the patenting of germ plasm or the “ownership of life”
• the perceived threat to third world farmers
• application in human reproduction – i.e. “designer” babies and human cloning
• control of scientific development and application by multinationals
• excessive focus of research funding towards biotechnology
• the trade war between the US and Europe
• enforcement of environmental liability with respect to GMO release
• misuse of genetic information in the insurance sector

ICSTI has identified a number of public concerns related to the application of modern biotechnology that are important in a national context. These will be addressed, together with the potential of the technology, in the following examples:

1. Antibiotic resistance genes in GM plants

2. Biotechnology in food production

3. Biotechnology in crop production

4. Virus genes in GM plants

5. Gene therapy

6. The application of biotechnology for bioremediation of contaminated sites

7. Genetic testing

ICSTI accepts that the above list is not comprehensive and that some concerns are not addressed in detail in the following sections.

5.1 Antibiotic Resistance Genes in GM Plants

Much concern has been expressed about antibiotic resistance genes in GM plants. Concern has arisen because antibiotic resistance in bacteria is a major health problem of which microbiologists and doctors as well as the general public are very much aware. The scientific community, worldwide, has taken these concerns very seriously.

Concerns about antibiotic resistance genes were raised on page viii of the summary of the Consultation Paper on “Genetically Modified Organisms and the Environment”, published by the Department of the Environment and Local Government, August 1998.

The four concerns that are described are related to each other:

i. Reduction in the usefulness of antibiotics in human and veterinary medicine

ii. The theoretical possibility of antibiotic resistance genes being transferred to soil and non-soil microorganisms (and to other organisms), thus increasing the pool of antibiotic resistance genes in nature

iii. The possibility of antibiotic resistance genes being transferred to pathogenic organisms

iv.Whether the use of antibiotic resistance genes in GM plants is necessary at all and whether the genes could be deleted once they have served their primary function.

The first three concerns are essentially the same – i.e. the possibility of compromising the use of antibiotics in the treatment of human, animal, and plant diseases.

There is a consensus world-wide among microbiologists that antibiotic genes used in making GM plants will not pose any significant risk to human or animal health for the following three reasons:

1. The genes are very unlikely to be transferred to and expressed in pathogenic bacteria

2. If the genes are transferred and expressed, the bacteria will not pass on the gene because there is no advantage in having antibiotic resistance unless the antibiotic is present.

3.There is a huge background of antibiotic resistance genes in the natural bacterial population. These genes are a cause for great concern and dwarf the dangers posed by GM crops, which should be considered in relative terms as minimal.

Antibiotic resistance genes in GM plants will not affect the usefulness of antibiotics which are important in human or animal health. The theoretical possibility of such genes transferring from plants in the fields to microorganisms, which are pathogenic and which may infect man or animals and cause disease, is practically zero. However, there is a theoretical possibility that such genes might transfer to bacteria in the digestive system from GM crops used as animal feed, but the chances of propagation are insignificant in the absence of selective pressure.

The risk from GMOs of transferring antibiotic resistance genes and propagating antibiotic resistant bacteria is insignificant compared to the risk of this occurring from the widespread use of antibiotics in medicine, veterinary medicine, animal feeds and crop framing. Farmers in the US currently spray certain crops with antibiotics (to control Erwinia, Pseudomonas and other microbial pathogens of plants). This practice is unwise since it will increase the number of antibiotic resistant bacteria. Moreover, it could provide a selective pressure without which antibiotic resistance genes in GM plants could not spread (see below). There is a strong case that it should be illegal to spray antibiotics on plants or to add antibiotics to animal feed.

The possibility of transfer of antibiotic resistance to pathogenic microorganisms can be assessed by comparison to the “natural background” population of antibiotic resistant bacteria. Genes for antibiotic resistance are widespread in nature and are especially frequent in places where antibiotics are used. The risk of antibiotic resistance occurring in bacteria is higher on farms and in hospitals where antibiotic use is high. The number of antibiotic resistance genes in GM plants will always be minuscule by comparison to their numbers in the natural microbial population.

Genes in plants are not readily transferred to bacteria. Even under the most favourable laboratory conditions, antibiotic resistance genes in plant DNA very rarely transfer to bacteria. These laboratory conditions included the use of purified genetic material (DNA) from GM plants, specially chosen bacteria as recipients, and selection for transfer by exposure of the recipient bacteria to the test antibiotics.¹⁷

If an antibiotic resistance gene does transfer in the field from a plant to a bacterium, this gene will not spread through the bacterial population because it will not confer any advantage to the bacterium in the absence of the selective pressure of the antibiotic itself. Antibiotics, such as penicillin (or ampicillin), kanamycin, hygromycin or streptomycin, are not spread on fields of crops (except, as indicated above, for control of Erwinia, Pseudomonas and other plant pathogens in the US). Consequently, there is normally no selective pressure to select for microorganisms which have picked up the gene for antibiotic resistance. The genes for hygromycin-resistance or kanamycin-resistance are usually under the control of promoters (genetic switches) which are not active in bacteria. If, by chance, such a gene does transfer to a bacterium, it will most likely just be transferred to the descendants of that single bacterium (and rarely if ever to any other bacteria, especially not to bacteria of other species). Most lines of bacteria (and other microorganisms) become extinct in a relatively small number of generations (which can be seen, for example, in the studies of the evolution of flu viruses).

In any case, an antibiotic resistance gene, which is either not active (because it does not carry the correct genetic switch), or which confers no selective advantage, will be useless to the bacteria and will gradually decay by random mutation, and be deleted by chance or disintegrate into a pseudogene.

The antibiotic resistance genes used in plant genetic engineering are generally not relevant to the antibiotics used in clinical or veterinary medicine. The exceptions are streptomycin and ampicillin. There is no need to use streptomycin or ampicillin in plant genetic engineering experiments and these antibiotics are not now being used in the generation of GM crops intended for release. Genes encoding resistance to these two antibiotics were incorporated into some of the first GM crops as passengers, where they were and are harmless. However, due to public concern, it has now been accepted that these two antibiotic marker genes will not be used in plant genetic engineering in the future. This sort of response only serves to vindicate public concern. If a process that is safe is made illegal, the public are led to believe that the process was unsafe from the outset. The two genes which are currently used in the majority of plant genetic engineering processes encode resistance to kanamycin (nptII) and hygromycin (hpt). Kanamycin is very rarely used and hygromycin B is not used in human medicine.

Horizontal Gene Transfer

Concern has been expressed about the phenomenon of horizontal gene transfer, that is the transfer of genes from one species to a different species. Genes are normally transferred vertically from one generation to the next within the same species. One of the remarkable achievements of genetic engineering has been the invention of novel and efficient, experimental mechanisms for horizontal gene transfer. For example, the human insulin gene has been transferred to bacteria and yeasts, and today all diabetics can be treated with human insulin made in bacteria or yeasts under the direction of the human insulin gene. This and similar systems are important contributions of genetics to medicine.

It has been alleged that horizontal gene transfer is unnatural and therefore dangerous. Specifically, people have been concerned about the horizontal transfer of bacterial genes for antibiotic resistance into plants. It has been alleged that this process is somehow likely to unleash a plague of antibiotic resistance genes because we have crossed a critical boundary which demarcates bacteria from plants. In other words, horizontal gene transfer might cause a catastrophe because it is intrinsically dangerous. This kind of assertion causes anxiety because it refers in a striking way (consider the impact of the words “horizontal gene transfer”) to something which the public know little about. In fact, horizontal gene transfer has been known since the discovery of resistance transfer factors by Watanabe and others in Japan in the 1950s. It occurs widely in nature¹⁸, though not so widely as to prevent the phenomenon of speciation (which Darwin rightly identified in “The origin of species” as a remarkable feature of the kingdom of living organisms). Vertical gene transfer is the norm but horizontal gene transfer is an important natural phenomenon which carries no general intrinsic dangers.

Conclusion

Antibiotic resistance genes are very unlikely to be transferred from GM plants into other organisms. If they do, they will not spread in soil or gut organisms because they are not being selected, and will therefore disappear or decay. The pool of antibiotic resistance genes in pathogenic microorganisms and their close relatives is so large that the impact of occasional and temporary transfer of such genes from GM plants will be vanishingly small and presents no cause for concern.

5.2 Biotechnology in Food Production

In the 1999 Eurobarometer¹⁹ survey carried out by the European Commission, respondents were asked to rank the benefits of seven biotechnology applications. The most beneficial application of biotechnology was considered by respondents to be detection of hereditary diseases. The least beneficial was the production of GM foods. This survey highlights the increasing level of concern within the EU about food safety.

This concern is of relatively recent origin. It arose initially as a result of the debate, within Europe, on the use of growth hormones in cattle, and was exacerbated by the emergence of BSE and by the proven link between BSE in infected cattle and new variant CJD in humans. The result has been an erosion of the public’s trust in regulatory authorities, scientists and politicians. Since the advent of GM foods coincided with this growing concern about food safety, it is not surprising that the public views GM foods with suspicion and requires reassurance about their safety. In the recent Eurobarometer survey, 26% of EU citizens questioned were of the opinion that consumer organisations were most likely to tell the truth about GM food safety, followed by the medical profession (24%) and environmental protection organisations (14%).

If GM foods are to be accepted by the European public, there is an evident need for open and informed debate about their benefits and risks. The potential benefits of the use of GM foods are addressed in section 5.2.1. Public concerns are considered in section 5.2.2.

5.2.1 Benefits of the Application of Biotechnology in Food Production

Biotechnology has been used in food production since ancient times. As illustrated in section 4.3, the selection and breeding of improved animal and plant strains, fermentation of milk to produce cheese, yoghurt and other dairy products, alcoholic fermentation to produce beers and wines, use of yeast in bread leavening, are all examples of applications of traditional biotechnology. In more recent times, advances in fermentation technology, availability of defined microbial starter cultures, developments in protein separation techniques, and use of purified enzymes in alcoholic beverages, cheese and other processed foods have greatly increased the role of traditional biotechnology in food production.

The use of recombinant DNA technology in food production and food processing reflects the application of our growing knowledge of biological systems to traditional biotechnological processes. One of the best known examples of recombinant DNA technology is provided by the cheese-making industry. Rennet is an enzyme that has traditionally been extracted from the stomachs of calves and used in the clotting of milk proteins to produce cheese. More recently, the enzyme chymosin has been produced from genetically engineered moulds, yeast and bacteria into which the bovine gene was introduced. Cheeses made using chymosin do not differ from traditional products with respect to flavour, texture or appearance. Since only the purified enzyme is used, cheeses produced using chymosin do not contain any trace of GM DNA. The guaranteed availability and cheaper cost of chymosin has been welcomed by cheese manufacturers and accepted by animal rights and vegetarian groups because of its replacement of calf rennet.

In the food sector, biotechnology is not solely applied to food production and food processing. It has many other uses, such as evaluation of food safety, improvement of nutritional quality and generation of food ingredients.

(i) Food Safety

The safety of human food and animal feed is an absolute priority which must be assured in order to maintain or expand food markets. In recent years, there has been a dramatic increase worldwide in food-borne diseases which has, to some extent, been linked to new food processing techniques which may compromise food safety. This increase has been linked to the production of “ready-to-eat” convenience foods which may contain a wide variety of diverse ingredients, and to the current availability of minimally processed foods and food products containing reduced levels of preservatives. Storage and display of these foods, particularly at incorrect temperatures, may also provide opportunities for growth of any pathogenic bacteria present in these foods.

The application of molecular biotechnology techniques may offer greater sensitivity in the rapid detection of pathogenic bacteria in food. Genetic characterisation of food-borne bacterial pathogens will help us to understand why certain bacterial pathogens survive and grow in individual foods, and may also unravel the complexity of pathogen/host interactions. Research is also ongoing on the role of inhibitors, such as bacteriocins, and on the potential use of protective bacterial cultures with the ability to competitively inhibit growth of bacterial pathogens. These research initiatives represent a proactive use of biotechnology to ensure food safety and reduce dependence on chemical preservatives in some foods.

The safety of foods may also be compromised by a range of threats over and above those posed by pathogenic bacteria. Contamination of grains and other dry foods by pathogenic fungi results in the production, within the food, of highly toxic and carcinogenic aromatic compounds (aflatoxins). Viral contamination of foods is currently considered to be responsible for the majority of gastroenteritis incidents world-wide. Biotechnology research is also focussed on developing sensitive techniques for the detection of aflatoxins and viruses in foods.

(ii) Health and Nutrition

In response to the growing consumer awareness of the relationship between diet and health, there is a need for increased biotechnological research towards improving the nutritional status of many foods. Research is unveiling the existence within milk and meat of novel health promoting components, some of which are currently being exploited for the development of added value ‘Functional Food’ ingredients or “Nutraceuticals”. This is an area where biotechnology may provide new opportunities for the food industry. For example, the application of biotechnology to this area will allow the enrichment of foods with health promoting components, such as vitamins, bioactive peptides and certain fatty acids.

Probiotic foods are currently the best known examples of functional foods in Europe, with health claims ranging from alleviating symptoms of lactose intolerance, treating diarrhoea, suppressing cancer and reducing blood cholesterol. Dairy foods such as cheese and yoghurt provide the ideal food system for delivering these health-promoting bacteria to the human gut. However, research is needed to improve the technological properties of these bacterial strains and to confirm the health claims associated with their products. The enhancement of the health status of food by such innovative approaches should aid in industrial diversification into high value added food markets, in addition to improving overall public health.

(iii) Improvements in Food Processing

The quality of food rather than the price is becoming the dominant feature of competitiveness in the food products and food ingredients markets. In this respect, there are a number of examples where biotechnological approaches are being adopted to improve and guarantee food quality.

Biotechnology can be used to great effect in the development of novel starter cultures required for the production of fermented foods. Over the last 20 years, there has been an intensive worldwide effort into the genetic characterisation of starter and probiotic bacteria used in the food industry. The results of this research have included development of efficient systems for their genetic improvement and characterisation of the genetic determinants which govern much of their industrial traits. Consequently, the exploitation of biotechnology for starter culture improvement can produce strains which produce acid more consistently, which are less sensitive to bacterial viruses (phage) and which produce anti-microbial compounds, thereby improving food safety. Moreover, the analysis of the total genetic make-up of these strains will facilitate their further modification through a process referred to as metabolic engineering where cellular metabolism can be directed towards the increased production of desirable end-products, such as certain flavour compounds and amino acids.

Other applications include developing novel enzymes for meat and dairy food processing and using molecular techniques to define the key determinants of food flavours and aromas. The availability of new enzymes from novel sources will enable the food sector to develop a more diverse product range, and may also allow application of less severe processing technologies.

5.2.2 Concerns Relating to the Use of Biotechnology in Food Production

It is accepted that many consumers have concerns, queries and objections to the use of GM organisms in food production and food processing. These concerns include:

• the potential transfer of foreign genetic material into other organisms, including humans
• the use of antibiotic resistance genes in the development of GM bacterial and plant species used in the production of GM foods
• potential toxic or allergenic effects resulting from introducing new genes, and their products, to GM foods
  
• patenting of germ plasm by multinational companies; threats to third world farmers; “ownership of life”; environmentally damaging effects on biodiversity.

(i) Is There the Possibility of Transfer of Foreign Genetic Material Into Other Organisms Including Humans?

Horizontal gene transfer is the movement of genetic information (DNA) between different species. Concerns have been expressed regarding the possibility of DNA introduced into GM species transferring into other bacteria, human or animal cells and whether there might be risks associated with such a transfer.

Experiments have shown that DNA remaining after digestion consists of very small fragments and have failed to show survival of intact DNA in stools or blood of animals fed with large quantities of DNA. There is no reason to believe that DNA in GM plants would behave differently. According to the Royal Society, UK, there is no evidence to date for transfer of intact genes to humans, either from bacteria in the gut, or from foodstuffs such as potatoes, wheat or chickens, despite daily consumption of DNA in the diet.

It should also be noted that DNA from GM crops is, in many cases, not present in the part of the plant that ends up on the supermarket shelf. Transgenic GM soya plants contain foreign genes introduced to confer resistance to particular herbicides. However, the process used to refine the oil produced from GM soya ensures that the product placed on the market has no detectable trace of the genetically modified DNA or of the foreign proteins expressed in the GM soya plants.

(ii) Is There a Possibility that Antibiotic Resistance Marker Genes Used in GM Foods Could be Transferred to Humans?

This issue has already been discussed in section 5.1. The general consensus is that antibiotic resistance genes are unlikely to be transferred from GM plants into other organisms. Recent developments have also made it possible to use alternative “marker” gene systems, which do not use genes for antibiotic resistance.

(iii) Are Genetically Modified Foods Safe to Eat?

There is no evidence to date that GM foods pose a greater risk to human health than their traditional counterparts. The independent GMO and Novel Foods Sub-Committee of the Food Safety Authority of Ireland (FSAI) reviews each new food separately to ensure that it complies with specified safety criteria. If this Sub-Committee is of the opinion that a GM food is not safe, or if it requires further information before reaching a decision, an objection can be raised at EU level.

It is the opinion of the FSAI Sub-Committee that GM ingredients currently on the market in Ireland are as safe as their traditional counterparts. The report²⁰ of a workshop organised by the European Federation of Biotechnology (EFB) and the European Molecular Biology Organisation (EMBO) in Dublin in April 1999, also confirmed that risks to human health from GM foods are minimal and are no different from those associated with traditional foods.

(iv) Is There the Possibility that the Introduction of Genes from Other Species May Cause Toxic or Allergenic Properties in GM Food Products?

Concerns have been expressed²¹ that:

• the introduced gene product may itself be toxic
• the introduced gene may lead to production of toxins in the GMO
• the introduced gene may modify allergenic properties of crops used for human food and animal feed production or may enhance the allergenic properties of the pollen of flowering plants.

All GM food products undergo a rigorous safety assessment before being released onto the supermarket shelf. In Ireland, the Food Safety Authority of Ireland is the compotent authority for the safety assessment of GM foods.

Before any GM food or food ingredient can be sold in the EU it has to be scientifically assessed by specialist scientific committees in each Member State. If any of these committees have objections based on scientific grounds, the product is rejected and referred to the European Commission Standing Committee for Foodstuffs where it is re-assessed. In order to obtain clearance to the market, the Committee must vote by a qualified majority in its favour.

(v) Should Foods Derived from GM Crops or Containing GM Ingredients be Labelled?

Many consumer organisations consider that labelling is essential for ascertaining the origin of foods, and in particular for separating GM from non-GM foods and for monitoring possible adverse effects of ingredients. The current labelling position in Ireland is outlined in Table 1, under Regulations 258/97, 1139/98 and EU Directive 49/200 and 50/2000. This situation is currently being reviewed at EU level.

The Food Safety Authority of Ireland supports the consumer’s right to know whether or not a particular food contains GM ingredients. This support for labelling is based on the Authority’s belief in consumer choice rather than on any food safety concerns.²²

It is the view of ICSTI that foodstuffs containing GM material, where the new foodstuff is substantially changed from that of its conventional counterpart, should be labelled in order to allow consumer choice.

Conclusion

There is no evidence to date that foods derived from GM crops or foods containing GM ingredients pose any greater health risks to man and animals than those posed by traditionally produced and processed foods. In order to allow consumer choice, foods placed on the market, that are produced or processed using recombinant DNA technology, should be clearly labelled. As with all foods, rigorous safety assessments should be carried out before release of GM foods to the marketplace.

5.3 Biotechnology in Crop Production

In the next decade, the arable crop sector and the agri-food industry will operate in a rapidly changing world environment due to increased competitiveness, globalisation of prices, and consumer demands for food quality, safety, health enhancement and convenience. It is, therefore, imperative to adopt new and innovative techniques to improve the competitiveness and efficiency of the crop and agri-food sectors. Innovation is essential for sustaining and enhancing crop productivity, and has always involved new, science-based products and processes which have, in the past, contributed to increased crop productivity. Ireland’s capacity to compete in the future is dependent on the quality of its technology and the capacity of its producers and processors to apply that technology. The enabling technologies that constitute biotechnology have introduced a new dimension to crop productivity improvement. Key core technologies will need to be developed to supply the appropriate crops and ultimately food products for an increasingly discerning and well-educated consumer.

The main initial focus of the use of biotechnology to produce the first generation of genetically modified crops was to reduce input costs for control of insect pests and plant diseases. This was achieved by a combination of efficient breeding, exploitation of resistance factors, and by development of GM crops with traits which reduce or eliminate the need for pesticides. A consequence of using GM crops is a reduction in environmental risk due to decreased application of agricultural chemicals. Biotechnology, combined with efficient plant breeding is, in fact, a low-risk alternative to previous conventional practices and is the most cost-effective method for controlling pests and disease. This approach has already led to a reduction in the use of sprayed chemical insecticides and to decreased environmental impact. Failure to control fungal disease in plants allows generation of fungal toxins, such as aflatoxin and fumonisin, which have severe negative consequences for human and animal health. Biotechnology can overcome these problems leading to safer and more nutritious food products which will be longer lasting and probably less costly. The development of plant-based oral vaccines, which will allow disease immunity to be achieved through dietary supplementation, will also give safer food products.

Environmental Concerns

Among the ecological issues associated with transgenic crops is the possibility that some newly introduced traits, such as pest or pathogen resistance, could confer added fitness to the crop. As a result, the crop may gain weedy characteristics if its ability to survive and spread outside of cultivation is enhanced. A second issue arises if such crops are grown in the vicinity of compatible wild or weedy related species. Transfer of the trait by natural hybridisation may produce a hybrid progeny that is more aggressive or more difficult to control.

Response: There is general recognition that conventional agricultural activity entails environmental and ecological risks. Genetically engineered pest resistance traits, currently being field tested or commercially released, present no fundamental differences from similar traits bred into crops using traditional techniques. Some scientists and plant experts disagree with this hypothesis and contend that transgenes will have more profound effects on crop phenotype than traditional genes, and thus may have potentially greater impact on weed species. There is no evidence to-date to support this view. However, the way in which future crops are engineered with multiple pest resistance or other fitness traits presents more complex ecological questions. Such “gene stacking” to confer resistance against a broad spectrum of pests may give recipient plants a greater selective advantage and lead to ecological consequences that are less predictable than the single-gene pest resistance traits which constitute much of our experience to date.

On the other hand, insecticides currently used in conventional agriculture kill some beneficial insects in addition to the target pest. However, the use of Bacillus thuringiensis (Bt) crops should lead to a reduction in the use of insecticides, thereby decreasing the impact on these beneficial insects and leading to greater sustainability.

Effectiveness of Pest Resistance Genes

Pest and disease resistance has been a primary objective of farmers and breeders throughout the history of agriculture. Using traditional breeding techniques, pest resistance genes identified in wild germplasm have been incorporated into cultivated varieties of many major crop species. This process is now being supplemented by the techniques of genetic engineering and dozens of crop species are being engineered for improved pest resistance. In genetically engineered crops, most insect resistant cultivars express cry genes from Bacillus thuringiensis, a gram positive soil bacterium which is noted for its abundant production of insecticidal proteins. One of the obstacles to approval for commercial growth in Europe of GM crop species is the potential for insects to become resistant to the Bt toxin.

Response: It is possible that insects could become resistant to the Bt toxin. This is also the case when pest resistance genes are introduced into plants using conventional plant breeding techniques. Resistance is a natural process of evolution and is inevitable regardless of whether the Bt is produced naturally in the plant or sprayed directly onto plants as currently happens in organic production systems. In order to reduce the likelihood of resistance taking place, there is certainly a need to develop strategies which would reduce the overall selection pressure. One such approach involves maintaining non-Bt refuges to thwart the emergence of the resistance phenomenon. Other strategies are also being developed which would reduce the possibility of resistance taking place – e.g. developing plants which would synthesise the Bt protein at a particular time when the crops are most at risk from the pathogen. Such an approach would also reduce the selection pressure and greatly reduce the possibility of resistance developing.

Over-Reliance on Pesticides

Concern is often expressed that the development of plants with built-in resistance to certain herbicides could lead to the over-use of these herbicides leading to possible damage to plants, insects and a range of soil organisms.

Response: The reality is that crop biotechnology has the potential to reduce the dependency of agriculture on chemicals, and the development of herbicide tolerant crops should lead to an overall reduction in the total amount of herbicide used. In trials carried out by Teagasc at the Crops Research Centre in Carlow, herbicide tolerant sugar beet reduced the level of herbicide usage by 50%. It also allowed substitution of chemical herbicides that persist in the soil with environmentally friendly alternatives, leading to more sustainable farming systems. For example, Glyphosate is one of the most environmentally friendly herbicides ever developed and is widely regarded for its lack of persistency, low risk of groundwater contamination and safety towards fauna. The World Health Organisation classifies Glyphosate as having minimal toxicity to humans, animals, birds and bees.

Herbicide Tolerant Plants and Superweeds

It has been contended that herbicide resistance could be transferred to weeds in hedgerows and ditches leading to the creation of superweeds resistant to herbicides.

Response: The possibility of transfer of herbicide resistance genes to weed species would depend on whether or not there is a closely related weed species present. If such related weed species are present, gene transfer could take place. The consequence of such an occurrence is not considered to have any great significance, as herbicides are not sprayed onto hedgerows and, consequently, herbicide-tolerant weeds would have no survival advantage over other plants in the ecosystem. Herbicide tolerant weeds could cause difficulties if they grow in fields where they need to be controlled. Under these circumstances, farmers would have to use a different herbicide. At present, farmers mix different herbicides and practice crop rotation to control various weed problems and could do the same with GM crops if weed herbicide tolerance became an issue. Farmers could also grow another GM crop that was tolerant to a different herbicide, thereby solving any difficulties which might arise. It is difficult to predict if herbicide tolerance is likely to develop in weeds in the future. Herbicide tolerant crops have been bred and used in conventional agriculture for many years and, to date, no adverse effects have been shown. Nevertheless, it is important that research is continued to assess the potential for transgenic pest resistant crops to become problem weeds, or to enhance the weediness of nearby sexually compatible relatives. This is a complex task, and information is required from many disciplines – e.g. weed science, agronomy, population biology, genetics, entomology, plant breeding, ecology, plant pathology, molecular biology, and others. Scientific evidence in support of informed risk assessment and decision-making thus lies in the collective knowledge of experts from these fields.

Could Genetic Engineering Result in Unforeseen Problems?

It is often argued that information on the science of genetic engineering is incomplete and that genes could inadvertently be altered which might lead to unforeseen problems later.

Response: Classical plant breeding has been the norm for over 100 years. While very significant progress has been made, the procedures have been very much hit and miss. For example, the process of hybridisation involves the mixing of millions of genes with no complete control over the outcome. Molecular methods, on the other hand, are more specific, and users of these methods will be more certain of the traits they introduce into plants facilitating greater precision and safety. Since the technology allows for a specific gene controlling a specific trait to be identified and copied, it is a far more precise technique than the trial and error approach of traditional plant breeding. In addition, marker assisted selection, a new molecular technique for confirming the presence of traits, is also a powerful new tool for improving crop quality, fertiliser use efficiency, disease resistance and the plant’s ability to withstand a range of biotic and abiotic stresses.

Seed Ownership/Patenting

Genetic diversity has always been an important component of plant breeding programmes, both nationally and internationally. Concern has increasingly been expressed regarding the involvement of large multinationals in the take-over of many plant breeding companies world-wide and the possible control and patenting of the world’s germplasm.

Response: While there is some substance to this view, the present reality is that only 17% of the current world seed supplies are controlled by large multinational companies, with 66% of seeds coming from state owned and farmer controlled companies. Local adaptation will become more and more important in the varieties of the future. Consequently, it is imperative to support local crop breeding programmes both in the developed and less developed regions of the world. The continued support of World governments to international plant breeding institutes such as the International Maize and Wheat Improvement Centre (CIMMYT) in Mexico and the International Rice Research Centre (IRRI) in the Philippines is warranted. The provision of varieties that are finely adapted to the “Irish production environment” should be a central theme for this country.

Patents for genetically modified plants are available in the US, Europe and Japan. If the possibility of patenting was denied, the absence of a financial incentive to develop new products would make it difficult for companies to make large investments in research, since the results would be available for anybody to copy. However, the patenting of a particular GM crop only means that the company concerned has the right to benefit from a specific application for a specific period of time, and has no automatic right to use the invention as it may be blocked by health, safety or environmental regulations.

Conventional Versus Organic Farming

Conventional farming methods are regarded by many as undesirable because of potential negative effects on the environment, biodiversity and sustainability. A move to organic production systems is seen as the ideal.

Response: All types of farming have some impact on the environment and new techniques are continually being developed to minimise any negative effects. Organic farming is no different –e.g. copper sulphate applied to organic crops as a disease control measure can cause toxicity to beneficial soil organisms, such as earthworms. GM crops, on the other hand, could solve many problems currently faced by farmers while at the same time bringing environmental and agricultural benefits.

Research Areas of Importance in an Irish Context: Cost Reduction and Decreased Environmental Impact

(i) Grassland

Since grassland occupies nearly 90% of the total land area in Ireland, grass productivity is of crucial importance nationally. Consequently, it is imperative that we use whatever techniques are available to increase the nutritive value of grass, as well as increasing output. It is certain that biotechnology will make a significant contribution to achieving these goals. Since many gene sequences are common to both wheat and grasses, comparative mapping can be used to elucidate traits which require targeting and incorporation into new and improved cultivars which will be very important nationally.

The development of marker genes (in ryegrass species) for early growth, leafiness, seed ripening, tolerance to low temperature and secondary compounds, including tannins, lignins and phenolics, should lead to improved varieties with the potential to produce higher yields of digestible dry matter. The overall net benefit of improved grass varieties could be as high as €130 million annually to the Irish economy.

The elucidation of the functional relationship between traits, such as high sugar content, and underlying metabolic pathways could increase grass sugars by at least half their current concentration. This should remove the need for silage additives, which currently are required to ensure good grass preservation, and lead to potential annual savings of €6.35 million. Grass intake should also be improved leading to increased milk and beef production with consequent improved efficiencies amounting to €45 million annually.

In clover breeding, optimisation of growth and increased nitrogen fixation rates, together with greater disease resistance, are likely to increase the potential of legumes for reducing fertiliser inputs and boosting quality. Reducing the likelihood of clovers to cause bloat in grazing animals is another long-term target which could be greatly enhanced with modern tools of biotechnology. Developments in clover breeding, utilising new molecular techniques, could reduce the need for artificial nitrogen fertiliser by approximately 50 kg/ha, leading to savings of at least €26 million per annum and a significant reduction of the current negative environmental impact of synthetic fertiliser use.

(ii) Pest and Disease Resistance in Cereals

Pest and disease resistance in plants can be maximised in breeding programmes for the major arable crops of national strategic relevance, particularly barley and wheat. Disease resistance in modern cultivars has a relatively short life span unless protected by frequent spraying with fungicides. This type of resistance is often unstable, breaking down as the pathogen adapts to the change in selection pressure. Consequently, the identification of markers to improve the selection efficiency for resistance to Septoria spp. is of high priority. Success in this area could significantly reduce the need for fungicides and save farmers 13 million euros annually in fungicide costs.

Plant viruses have developed many novel ways of moving from one infected plant to another using vectors, such as aphids. Consequently, the control of barley yellow dwarf virus (BYVD) in cereals requires the routine application of insecticides to control the vector. Unfortunately, other beneficial insects are also killed. Using molecular techniques to introduce virus resistance into new varieties would have significant benefits for both the grower and the environment, as the need to routinely apply aphicides would be greatly diminished.

Conclusion

If GM technology is considered to be hazardous in introducing new gene combinations in the development of new crop plants, then it is likely that the same or perhaps even greater hazards arise from the use of conventional plant breeding.

5.4 Virus Genes in GM Plants

Viruses consist of either DNA or RNA surrounded by a coat of proteins called a capsid. They reproduce by entering the cells of animals, plants or microbes, taking control of the host cellular activities to make more viruses and usually killing the host cell in the process. The genetic material of the infecting virus dictates the structure of the newly formed viruses. The capsid proteins help to protect the genetic material and assist with the entry of the virus into a host cell.

Most plant viruses have RNA (rather than DNA) as their genetic material. However, some of the DNA-containing plant viruses, such as the Cauliflower Mosaic Virus (CaMV), are economically important and have been widely studied. After infection of a plant cell with CaMV, the viral DNA is transported to the nucleus and, following some processing, is used as a template for making RNA copies of the DNA (transcription). The RNA is exported from the nucleus to the cytoplasm where it is used both as an information source for making the enzymes and capsid proteins necessary for assembling new viruses (translation) and as a template for making new virus DNA using the reverse transcriptase enzyme.

Many GM plants have viral capsid protein genes or viral regulatory sequences deliberately incorporated into their genomes. The insertion of viral capsid genes in some GM plant genomes results in the production of capsid proteins by the plant cell, thereby often rendering the cell resistant to the particular virus from which the capsid gene was obtained.

The regulatory viral gene most often incorporated into GM plants is the Cauliflower Mosaic 35S promoter (CaMV promoter). A promoter is a section of DNA that promotes the expression of genes associated with it. The CaMV promoter is a very effective promoter in plants and has consequently been used to drive expression of genes inserted into GM plants. This is very important for maximising product formation in GM crops. The products either directly or indirectly under control of the CaMV promoter may include medically useful products such as vaccines or antibodies, nutritionally important products such as vitamins, or products to protect the plant against pests or disease.

Exchange of Genetic Information Between Viruses and Plant Viral Genes

There is some evidence that when two different viruses infect a plant cell simultaneously, the viruses can exchange genetic information – a process known as recombination. There is also some evidence that viral genes in GM plants may recombine with the genetic material of incoming viruses.

Suggested Dangers Arising from Interaction of Viruses with GM Plants

Suggested Danger No. 1: It is suggested that new, more virulent viruses might arise from the type of recombination event described above.

Assessment of Suggested Danger No. 1: The factors to consider here are the frequency of recombination events, the likelihood of producing a new virus with more severe symptoms and the fitness of any such new virus to survive in competition with existing viruses.

With respect to frequency, this is rather low but further research needs to be carried out to determine whether there is a significant difference between recombination frequencies in GM plants and non-GM plants. It is important to realise, however, that research has shown that natural co-infection by different viruses is extremely common so that in the natural order of things there is every reason to believe that most new combinations of viral genes will have already arisen naturally.

In laboratory experiments, new viral combinations with more severe symptoms can be found on rare occasions but usually only under conditions of active selection for such combinations. Although such strains may induce more severe symptoms, the new strains are almost invariably less competitive than existing viruses. There is only a single case where such a rearranged virus was found to have acquired increased infectivity. In this case, the virus had been repeatedly inoculated into host plants in a greenhouse situation, with the deliberate intention of increasing its infectivity. It is difficult to see how such a series of events would occur in a field situation.

Suggested Danger No. 2: Transcapsidation. This is a process that might occur when the virus coat proteins from a GM plant cell are used by an invading virus. It has been suggested that the new type of virus formed might have enhanced infectivity and may infect an extended range of hosts.

Assessment of Suggested Danger No. 2: While such a virus might initially infect a new host, it would be a dead end for the virus as the capsid proteins of the viruses arising from such an infection would be of the normal type specified by the virus genetic material.

Suggested Danger No. 3: Synergism. It is suggested that a virus gene in the GM plant cell might potentiate the effect of an incoming virus, thereby increasing the severity of its effects.

Assessment of Suggested Danger No. 3: While, in principle, it is possible that this might happen, the only plants affected would be the GM crop plants themselves as any non-GM crops or any GM crops with different virus genes would not potentiate the effect of any virus resulting from such an infection.

Suggested Danger No. 4: Outcropping of virus resistance genes to weeds. It is suggested that GM crops with virus resistance genes might outcross to weeds, making these resistant to the particular virus and therefore more prolific.

Assessment of Suggested Danger No. 4: This proposal is based on the conjecture that virus infection is a major controlling factor in weed proliferation. There is little or no evidence that viruses act as biological control agents for weeds. Furthermore, viruses are very host-specific and even if viruses could be shown to keep weed populations under control this could only apply to weeds very closely related to the crop plant itself.

Suggested Danger No. 5: “Naked” CaMV promoter from GM food plants may gain access to human cells when these foods are eaten. The CaMV promoter has a recombination hotspot that may cause it to recombine into the genome of a human cell. This insertion of the CaMV promoter into the human genome could potentially activate or inactivate genes, which could lead to cancer.

Assessment of Suggested Danger No. 5: The CaMV promoter gene is not, in fact, “naked”. It is part of the plant genome just like any other promoter gene in the plant. The possibility for uptake of CaMV promoter into humans is no different from any other plant gene. With fresh foods, the processes of digestion make it very unlikely that DNA pieces are taken up by human cells. With processed foods, this is even less likely. Cells have mechanisms for destroying foreign DNA that enters the cells. The CaMV promoter recombination hotspot is restricted to recombination within plant cells. What is more, it has been shown that 10% of the non-GM cauliflower and cabbage sold in a UK market was infected by CaMV. The cells of these plants contained up to 100,000 copies of the virus. It is likely that very large quantities of CaMV DNA have been consumed for as long as we have eaten cauliflowers and cabbages.

Conclusion

While there are many suggested dangers of using viral genes in GM crop plants, most of these do not withstand detailed scrutiny. The so-called dangers are little different from those that are presented by the natural presence of viruses and viral genes in the non-GM food that we consume. That does not mean we should abandon all caution in this respect. Development of GM technology employing virus genes should proceed judiciously in the light of current scientific knowledge. Where there are gaps or insufficiencies in our knowledge, research to eliminate these should be encouraged. At this time, it would be important to encourage research into:

(i) Virus recombination frequencies in co-infected GM and non-GM plants.

(ii) Frequency of recombination events between plant viruses and viral genes in plant genomes.

(iii) The part played by viruses in natural control of weed species.

5.5 Gene Therapy

Definitions

Gene therapy may be defined as the introduction of genetic material into the cells of a patient in an effort to help cure a disease, either by providing a protein which is missing from the patient due to a genetic mutation (e.g. Factor VIII protein for haemophilia) or by the introduction of new genetic material which either directly or indirectly will help to combat the disease (e.g. genetic vaccination). Therapeutic genes are delivered using a carrier (vector) which may be a nonfunctional virus vector or a non-viral vector such as liposomes. Current gene therapy protocols involve the introduction of genetic material into somatic tissue, such as blood cells, liver cells, etc. Somatic cell gene therapy precludes passage of the introduced gene to the next generation. This contrasts with germ line therapy which involves the introduction of a gene or genes into sperm, ova, or gonadal tissue, resulting in the possible inheritance of the gene(s) by the children of the patient. Germ line therapy is currently subject to an international moratorium.

Somatic Gene Therapy: Introduction of a gene into a specific tissue or tissues to provide a therapeutic benefit to the patient.

Germ Line Therapy: Introduction of genetic material into the egg or sperm cells of an individual such that the gene will also be passed on to the next generation.

Ex Vivo Gene therapy: Collection of the patient’s cells, introduction of therapeutic genetic material into these cells and reintroduction of these cells into the patient.

In Vivo Gene therapy: Direct injection of therapeutic genes to the relevant tissue via a vector.

The promise of gene therapy lies in its proposed ability to treat the causes of disease rather than the symptoms. The first decade of gene therapy has been somewhat of a ‘roller coaster’ ride, with early excitement of the potential of this approach being tempered by disappointing clinical results. It is important to note that for any therapy that is tailored to a molecular defect in a disease, the timeframe between identification of the gene defect and the potential application of a therapy which is specifically targeted to that defect may be greater than 10 years. However, two recent examples in the treatment of cancer show the promise of molecular medicine and targeted therapy. In breast cancer, overproduction of a particular oncogene product called her 2 leads to a form of breast cancer that is very resistant to treatment. The development and use of a monoclonal antibody (herceptin) to this protein has shown significant reduction in tumours in phase I and II clinical trials. In Chronic Myeloid Leukaemia (CML) a leukaemia specific tyrosine kinase protein called P210 is implicated in the disease and makes patients resistant to chemotherapy. The use of a tyrosine kinase inhibitor STI571 to directly affect the key molecular change in CML has shown dramatic clinical results and holds great promise for the treatment of this therapy resistant leukaemia. Furthermore, in the gene therapy setting, improvements in vector construction and vector delivery to the appropriate tissue have led to better pre-clinical and clinical results. One of the more important contributions of gene therapy to date has been in the use of viral vectors in laboratory research to help elucidate the function of genes and provide proof of principle of possible therapies.

Where Did Gene Therapy Begin?

The development of gene therapy, as we know it today, resulted from two significant advances in science and medicine in the 1960s and 70s – the advances in cellular and transplantation biology leading to effective bone marrow transplant treatment for leukaemia and advances in molecular biology and genetic engineering leading to the cloning of therapeutic proteins for the treatment of human disease. On 14 September 1990, the first patient was entered into a somatic gene therapy protocol. The 4 year old girl had a rare autosomal recessive disease, known as adenosine deaminase (ADA) deficiency, where copies of the gene for ADA in each cell did not function. As ADA deficiency leads to an immune deficiency syndrome patients are very susceptible to infection, and have to live in a carefully controlled environment. Blood and bone marrow cells were taken from the girl and an artificial copy of the ADA gene was introduced into these cells which were then returned to the patient. Despite an improvement in clinical symptoms, there is no evidence to date of a patient with ADA deficiency having long term ‘cure’ of their disease solely by gene therapy.

Relationship Between Gene Therapy and Currently Accepted Clinical Protocols

In some respects, gene therapy has strong connections to cell therapies such as bone marrow transplantation, and indeed many of the gene therapy protocols involve the use of bone marrow transplant techniques. One of the reasons for choosing ADA deficiency as the first disease to be treated by gene therapy was that it had already been demonstrated that allogenic bone marrow transplantation from a donor who was a brother or sister and showed a similar tissue type could cure this disease by providing the missing enzyme in the infused donor marrow. Particularly for enzyme deficiencies, allogenic bone marrow transplantation could, therefore, be considered as a ‘natural’ form of gene therapy. In a gene therapy type approach, the bone marrow or peripheral blood stem cells are taken from the patient and the missing gene is introduced into these cells. The gene-corrected cells are then returned to the patient where they begin to produce the therapeutic protein. While gene therapy has a long way to go, it may be relevant to draw a comparison with heart transplantation which went through initial cycles of enthusiasm tempered by the problems of the immune response/rejection issue; there followed years of basic research in an environment of great disappointment and finger pointing. Painstaking research and a degree of good fortune led to the resolution of the rejection issue through immune suppression and a procedure which has widespread acceptance today.

Gene Therapy: Status to Date

Gene therapy is just over 10 years old and is still in its infancy. However, more than 350 phase I and phase II clinical trials utilising gene therapy type approaches have been used world wide in the treatment of cancer and genetic disease. Cancer gene therapy protocols predominate, partially due to the fact that retroviral vectors are well suited for introducing material into cancer cells. In addition, approximately 30 gene therapy protocols for AIDS are currently in progress and several cardiovascular gene therapy studies are underway. The principles of gene transfer that have been developed are now being applied to the development of genetic vaccines which are currently being used in patients with AIDS. Preventive or therapeutic vaccines may soon be developed against malaria, tuberculosis, hepatitis A, B and C viruses, influenza virus and Ebola virus. Preclinical studies are also addressing the possibility of initiating new gene therapy programmes for autoimmune diseases, allergies and neurological disease.

Concern over the matter of safety of gene delivery has meant that this approach has been subject to peer review and open debate, which has helped to make it a safer clinical treatment. One area that is of concern is the use of viral vector delivery systems and the potential danger of damaging existing genes or promoting interaction between viral vectors and existing or new viral pathogens. Due to these concerns, many researchers are now developing safer non-viral delivery methods using established or experimental drug delivery methodologies. National legislation in several EU countries is favouring a non-viral approach in certain circumstances. While gene therapy has been accepted in the treatment of disease in children and adults, controversy has arisen over the proposal to begin in utero gene therapy clinical trials for the treatment of inherited genetic disorders.

Questions to be Asked About Gene Therapy

(i) Is Gene Therapy Different from Current Techniques?

While gene therapy is a novel protocol for treating patients with disease, it does have some parallels with conventional treatment which has led to important development and application of the technology. As indicated above, the comparison with bone marrow transplantation is a good one – particularly in the treatment of enzyme deficiency syndromes. Also in Cystic Fibrosis (CF), many patients are now being treated with lung transplants. One might say that somatic gene therapy is a less invasive procedure than the transplantation of a major organ, although at present the gene therapy protocols for CF are somewhat disappointing.

(ii) What Diseases are Suitable for Treatment? What are the Current Alternatives – i.e. Why Gene Therapy?

The question of what diseases should be considered for gene therapy is not an easy one and it is important that different diseases are considered on an individual basis for the pros and cons of a gene therapy type approach. Benefits of new treatments can have many different measurements; cure, partial cure, improvement of quality of life etc. Also particularly in diseases such as cancer, clinical advance will come from co-operation with other more established disciplines – such as chemotherapy, radiotherapy and immunotherapy. This is inevitable and necessary in order to prove that gene therapy can have efficacy as part of a combinatorial therapy, before hoping to move clinical mountains alone. There will have to be a thorough understanding of the clinical situations in which gene therapy will be used in order both to understand its own limitations, and to exploit its full potential. Inevitably, the issues of cost of treatment will also have to be taken into consideration. It must be realised that for early gene therapy protocols in particular diseases, the first patients entering such trials may provide much information that will help to guide future treatments but may not benefit personally from the treatment. Unfortunately, the experience in clinical medicine is that new therapies are not immediately 100% effective and this must be recognised both by the clinician and by the patient. Also the ‘newspaper breakthrough’ mentality should be approached with caution as with access to the Internet etc, many patients are now extremely up to date on new technologies and care must be taken to avoid offering false hope.

Issues to consider include:

• How representative are preclinical studies?
• Small benefits versus big benefits
• Gene therapy and current treatments versus gene therapy alone
• Gene therapy as last ditch therapy or gene therapy at an earlier stage where it may be more effective

(iii) Is There a Need for In Utero or Prenatal Gene Therapy?

Several diseases where some of the pathological changes manifest themselves during foetal life might benefit from an in utero gene therapy approach e.g. Cystic Fibrosis or Tay Sachs disease (B hexosaminidase A deficiency). However, one must realise that prenatal gene therapy concerns both the mother and the foetus. There must be a firm demonstration of therapeutic value before any protocols can be considered.

Concerns over in utero gene therapy include:

• Accidental foetal germline gene transfer
• Accidental maternal gene transfer
• Immunological status of the foetus – could mount an immune response against the viral vector leading to problems with infection later in life
• Access to the target organ in a reasonable and reliable developmental window

(iv) What are the Risks Associated with Gene Therapy?

As with any new therapeutic approach, it is important to identify and quantify the risks associated with the approach, taking into account both actual and perceived risks and counterbalancing them against perceived benefits.

Questions that we must address include:

• Is the vector used to deliver the gene to the appropriate tissue safe (i.e. no risk of replication competent retrovirus)?
• Is there a risk of the vector integrating with a gene activating an oncogene leading to the development of cancer.
• Is there a risk of the vector combining with other naturally occurring viruses which may infect the host?

The first two scenarios are quantifiable risks but need to be addressed stringently in in vitro and pre-clinical studies and should form part of the regulatory process before any patient receives any gene therapy product. The third scenario is an important one and researchers are currently investigating non-viral strategies to improve the safety of gene therapy approaches.

(v) Risk of Vector Going to a Different Organ and Causing Damage

This is an increasingly important area, particularly if in vivo gene therapy is being considered, since inappropriate expression of a particular gene product in a non-target tissue could have a detrimental effect.

(vi) Risk of an Immune Reaction to the Vector

This has been documented with a number of vector constructs, most notably adenoviral constructs.

Regulation of Gene Therapy

The US Recombinant DNA Advisory Committee (RAC) was established in 1975 and has advocated open and public discussion of advanced therapeutic products and protocols. Stringent vetting of proposals is performed and they stress the need for full disclosure of positive and negative results and potential side effects of gene therapy. The US Food and Drug Administration (FDA) issued a Note for Guidance on the use of human somatic cell therapy and gene therapy in March 1998. The European Commission communication (OJ EC C229/4 issued on 22/07/1998) provides details on human gene therapy and regulations but is currently being revised. The European Agency for the Evaluation of Medicinal Products (EMEA) has recognised the need for consistent regulations in relation to gene therapy. In February 1999 it published a concept paper (CPMP/BWP/2257/98) of its Biotechnology Working Party entitled “Concept paper on the development of a committee for proprietary medicinal products (CPMP) points to consider on human somatic cellular therapy”. This has led to the release of two papers, CPMP/BWP/41450/98 and CPMP/BWP/3088/99, for discussion and consultation which form the basis of current regulation of gene therapy and gene therapy products in Europe. In Ireland, the Irish Medicines Board (IMB) would use these directives and discussion papers in the evaluation of gene therapy protocols. The Environmental Protection Agency (EPA) would be the regulatory body in relation to research in this area but does not have any specific guidelines regarding gene therapy research – guidelines relate to GMOs and their release in general. Nevertheless, despite these regulations and proposed regulations in Europe and North America, in September 1999 the first death directly attributable to gene therapy occurred. The patient was being treated for an enzyme deficiency called ornithine transcarbamylase deficiency (OTC) as a part of a phase I clinical study. The patient was in the group that received the highest dose in the trial protocol of an adenoviral vector containing the OTC gene. He developed acute respiratory distress syndrome (ARDS) shortly after the gene therapy infusion and died two days later from organ failure. Measurement of cytokine levels indicated that he had systemic inflammatory response syndrome; all erythroid precursor cells were wiped out from his marrow and the vector had gone to other organs besides the liver. Subsequently the FDA found procedural problems and shut down all seven clinical trails at Penn’s Institute for Human Gene Therapy. Problems related to consent and death of two animals in a similar preclinical procedure, indicating that as in all other therapeutic approaches, there should be full and frank disclosure of any problems. There is a perception that there remains too much secrecy about gene therapy trials (Lancet, Jan 29 2000) and this needs to be addressed as a matter of urgency.

Other issues that are of similar importance relate to the consent of the individual undergoing the protocol, particularly in an experimental protocol, and the privacy of the patient.

It is imperative that the public are aware of global developments in gene therapy and that there is community wide discussion on this potentially important new therapeutic approach to disease.

It is important that gene therapy is regulated both at the research level and at the clinical level in Ireland. At the clinical level, the relationship between the EMEA and CPMP is an important one which ensures that any gene therapy trials that may take place in Ireland will be subject to European Guidelines. Regulation at the research level is less clear. It is recommended that a special committee should be established to regulate research in this area. Guidance and membership should be drawn from the Irish Medicines Board, the Health Service, the Environmental Protection Agency, Third Level Institutions, the Private Sector and other relevant agencies and interests.

Conclusion

Somatic gene therapy is ending its first decade. Research and technological advances have led to gene therapy protocols entering the clinic and being tested in various diseases. New and substantially improved vector systems and related technologies are undergoing development. Many have shown promise in animal studies, and some are now being used in clinical trials. However, further developments in gene-transfer vectors, gene-delivery techniques and identification of effective treatment genes will be required before the full therapeutic potential of gene therapy can be assessed. Safety issues should be considered and stringent controls put in place. More discussion and education in relation to gene therapy is an important part of its development as a useful clinical treatment. Appropriate authorities should be put in place to regulate research and clinical studies in this area.

5.6 The Application of Biotechnology for Bioremediation of Contaminated Sites

Bioremediation refers to the use of microorganisms, either in situ or ex situ, to remove pollutants from contaminated soil, sediment, aquifer, freshwater and marine environments. Bioremediation is usually applied for the treatment of sites contaminated by organic pollutants (hydrocarbons resulting from oil spillages or storage tank leachates; xenobiotic insecticides, herbicides, pesticides; pharmaceutical drugs, disinfectants, antiseptics; wood preservative agents, plasticisers, flame retardants, paint constituents, etc.). More recently, ex situ bioremediation techniques have been applied to inorganic (metal) contaminant removal from soils, sediments, aquifers and acid mine drainage wastewaters.

Traditional Methods of Remediation of Organic Pollutant-contaminated Sites

The requirement, under National and International law, to adopt a hierarchy of waste management that promotes: (i) waste minimisation, (ii) waste recycling/re-use, (iii) waste treatment and (iv) waste disposal, is of recent origin. The advent of the Industrial Revolution initially led to uncontrolled dumping of recalcitrant and potentially toxic organic wastes; hydrocarbon spillages; coal tar and heavy fuel oil residue dumping at district heating gas generation plants; leachate generation in poorly operated municipal and toxic waste landfill sites; unlicensed disposal of outdated chemical explosives, chemical and biological warfare weapons; the discharge of untreated chemical/pharmaceutical wastewaters, etc. The scale of historical organic contamination is of greater magnitude in those countries (i.e. former Soviet Union) where environmental legislation was slow to develop and where enforcement was rarely practised.

Although remediation techniques have focused on our legacy of historical organic contamination, it is worth pointing out that, even in the context of more enlightened environmental legislation and enforcement, illegal dumping and accidental spillage will inevitably occur, leading to future contaminated sites requiring remediation.

Earlier, non-biotechnological techniques for remediation of sites contaminated by organic pollutants employed incineration or extraction/treatment/safe disposal procedures. Incineration involves removal of the contaminated soil and sediment, followed by waste-to-energy combustion at high temperatures (> 1,500°C) and disposal of the ash residue in a controlled toxic waste landfill site. The operational and monitoring costs involved are extremely high and legislation preventing the trans-boundary shipment of toxic waste is currently limiting the application of this technology – i.e. the contaminated soil/sediment must be transported to an existing incinerator as the costs involved in commissioning an on-site incinerator would be prohibitive. Extraction of the pollutant from the contaminated site involves flushing with hot water, detergents or solvents, followed by either incineration or safe disposal in toxic waste sites. These traditional treatment methods will continue to be required for heavily contaminated soils and sediments and for organic pollutants that are not susceptible to microbial breakdown and mineralisation.

Non-biological remediation of contaminated marine environments has focused primarily on major hydrocarbon spillages resulting from tanker accidents (i.e. Mega Borg, Exxon Valdez, Torrey Canyon, etc.). Techniques used involve dispersal using detergents; off-shore containment and collection; shoreline recovery followed by incineration or landfill disposal.

In Situ Bioremediation of Sites Contaminated by Organic Pollutants

The objective of bioremediation is to degrade organic contaminants to stable, non-toxic end-products, such as carbon dioxide (CO2), methane (CH4), water (H2O), etc. In situ techniques involve stimulation of the biodegradative activities of competent, endogenous microbial populations in the affected sites by:

1. adding limiting inorganic nutrients (N/P) or trace metals

2. providing external oxidants, such as oxygen(O2), nitrate, sulphate, ferric iron, etc., required by species involved in aerobic or anaerobic respiration, or CO2 required by bacteria catalysing methanogenesis or homoacetogenesis

3. altering pH or temperature

4. providing non-toxic organic compounds required for co-metabolic degradation

In situ bioremediation may be enhanced by introducing bacterial inocula (natural or genetically engineered) to the contaminated site (bioaugmentation). Bioaugmentation is usually accompanied by nutrient and external oxidant supplementation in order to increase in situ mineralisation rates. If the site conditions permit, “land-farming” may be practised – i.e. removal of surface vegetation, followed by ploughing, tilling and raking of the soil in order to enhance aeration and ensure efficient distribution of inocula and nutrients. When carrying out bioremediation in situ it is important to ensure that nutrients, oxidants, other introduced chemicals, inocula or the organic pollutants being remediated do not migrate from the test site or cause eutrophication of marine or freshwaters. In practice, bioremediation in situ is a multidisciplinary biotechnological application, involving microbiologists, geneticists, chemists, hydrologists, geologists and environmental engineers.

Bioremediation in situ has been used successfully to clean up soils and sediments contaminated by hydrocarbons, coal tar, solvents, organic explosives (TNT), poly-chlorinated biphenyls (PCBs), poly-aromatic hydrocarbons (PAHs), creosote, DDT, etc., and marine and shoreline environments affected by oil spillages and groundwater aquifers contaminated by landfill leachates.

Ex Situ Bioremediation of Sites Contaminated by Organic Pollutants

Ex situ bioremediation is more usually applied to contaminated soils and sediments, rather than to aquifers, freshwater bodies or the marine environment. A number of options for soil and sediment ex situ bioremediation have been developed:

i. physically removing of the soil followed by composting under controlled conditions on specially-constructed platforms or after transfer to composting sheds. If necessary, bulking agents (straw, woodchips, etc.) are added to improve oxygen entry. Nutrients and bacterial inocula (natural or GMO) can also be introduced in order to speed up the composting process.

ii. removing the soil followed by its treatment (aerobically or anaerobically) under controlled and optimised conditions in bio-reactors.

iii extracting the organic contaminants from the soils and sediments (with or without removal from the site) using hot water, detergent solutions or solvents, followed by degradation of the contaminant(s) in bioreactors under optimised conditions.

Bioremediation ex situ of contaminated groundwater has been practised in a limited number of cases. This involves extraction of the groundwater followed by biological treatment in bioreactors or by re-circulating the contaminated water through the topsoil using landfarming techniques. Natural or genetically-engineered bacterial inocula, nutrients, etc. may be introduced during recirculation of the groundwater through topsoil.

Use of Natural or Genetically-modified Bacterial Inocula for Bioremediation

Bioaugmentation, using natural or GMO species, during in situ bioremediation, does not necessarily ensure more rapid rates of organic pollutant degradation. To date, bioaugmentation in the field has involved natural inocula only and the use of GMOs in situ has not been sanctioned. The success of introduced, competent bacteria to contaminated sites may be limited by their inability to compete with indigenous species under the prevailing environmental conditions; their susceptibility to predation by protozoans; their preferential use of non-pollutant organic substrates present in the eco-system and their sensitivity to toxic compounds present in the contaminated site.

Although bioaugmentation using natural inocula has been reported to achieve successful remediation of marine oil spillages, the findings in contaminated soils and sediments are conflicting and do not provide proven support for the beneficial effects of bioaugmentation. In many cases, insufficient controls were used to determine the effect of the introduced inoculum. In other cases, it was shown that the simultaneous addition of inorganic nutrients and oxidants (practised in virtually every case) led to enhancement of the activity of indigenous degradative species rather than to the growth and activity of the introduced non-indigenous species. For example, bioremediation of Hudson River sediments heavily contaminated by PCBs (printed circuit boards) involved introduction of hydrogen peroxide (H2O2, as a source of oxygen via biological and chemical oxidation), inorganic nutrients, biphenyl to stimulate co-metabolism and an inoculum of Alcaligenes eutrophus, strain H850 (a known PCB degrader). The results obtained suggested out-competition of the introduced Alcaligenes strain by endogenous bacteria in the sediment and its gradual die-off and disappearance from the test site. These findings are not surprising since the endogenous bacteria present in a given ecosystem have adapted over the millennia to the environmental characteristics of their habitat and are, therefore, much more likely to grow and multiply under favourable nutrient and oxidant conditions than an introduced species from a different ecosystem and cultivated, prior to inoculation, in a laboratory environment.

Ex situ bioremediation of contaminated soil/sediment slurries or extracted pollutants in bioreactors provides a more realistic use of competent natural inocula or GMOs. Aerobic, anaerobic or combined anaerobic/aerobic bioreactor treatment processes generally utilise complex mixtures of many different microbial trophic groups. Many of the microbial species involved have not, so far, been isolated and may be non-culturable using current procedures. Genetic analysis, using DNA or RNA probes, is presently providing an insight into the rich biodiversity of the microbial populations of organic waste treatment bioreactors. Consequently, it is likely that introduced inocula will also be subject to competition in bioreactors. However, the ability to control operating temperature, nutrient and oxidant supplementation and other operational parameters can be exploited to ensure that introduced inocula are favoured and that pollutant degradation rates are enhanced.

Concerns Regarding the Use of GMOs for Bioremediation

In Situ Bioremediation:

Concerns regarding the introduction of GMOs for in situ bioremediation include:

(i) possible persistence of the introduced species in the environment and potential negative impacts on the natural functioning of the ecosystem

(ii) transport of the introduced GMO(s) away from the original site of application with potential impact on other ecosystems

(iii) gene transfer from the introduced species to the indigenous population

(iv) difficulties in following the fate of the introduced species or genes within and without the test site.

Ex Situ Bioremediation

The use of GMOs during ex situ bioremediation in bioreactors offers the possibility of controlled application, containment and safe disposal. In many contaminated sites, indigenous species with the metabolic versatility required for biodegradation of complex xenobiotic organic pollutants are not present. Ex situ treatment, under controlled and optimised conditions in bioreactors, allows the use of genetically-modified organisms developed specifically for the degradation and mineralisation of specific xenobiotic pollutants. The persistence of many xenobiotic organics in the environment has recently been linked to the requirement for cycling of these compounds between anaerobic and aerobic environments for degradation to proceed efficiently. For example, azo-dyes must first be cleaved by anaerobic species that are incapable of further degradation of the cleavage products. However, aerobic species, that cannot catalyse the initial cleavage reaction, can fully degrade the resultant monomeric aromatic products. A similar situation exists with respect to polychlorinated aromatic compounds (insecticides, pesticides, germicides, etc.). Reductive dechlorination by anaerobic species results in the generation of mono- or di-chlorinated derivatives. While these derivatives cannot be further metabolised by anaerobic bacteria, they are readily mineralised by anaerobic bacteria that are incapable of dechlorination of the initial polychlorinated compounds. Ex situ bioremediation offers the feasibility of utilising sequential anaerobic/aerobic biological treatment systems under optimised conditions in order to facilitate the degradation of these persistent pollutants. It also provides an opportunity to utilise GMOs with specifically designed degradation capabilities under controlled and environmentally-acceptable conditions.

Benefits of Biotechnology for Remediation of Contaminated Sites

Although non-biological remediation techniques will continue to be required for restoration of heavily contaminated sites, bioremediation currently offers a valid biotechnological alternative for sites contaminated by an increasingly diverse array of recalcitrant and xenobiotic pollutants. It is unlikely that GMOs will be utilised or permitted for in situ bioremediation purposes. However, their use, ex situ, in bio-reactors for slurried soils or extracted pollutants under optimised and contained conditions provides a biotechnological application that can address and remediate the problem of xenobiotic compound accumulation, with resultant toxicity, in aerobic and anaerobic environments.

Many contaminated sites do not lend themselves to in situ bioremediation – i.e. cold environments where the ambient temperature does not allow stimulation of bacterial pollutant degradation, or high temperature desert environments where lack of water or excessive temperatures prevent in situ bioremediation. In these cases, pollutant removal requires ex situ treatment under optimised conditions in bioreactors, thereby permitting contained use of GMOs or natural competent degradative species.

Conclusion

Incineration, chemical treatment and landfill have been the methods of choice, until recently, for remediation of environmental sites contaminated by organic chemicals as a result of accidental or deliberate discharges. Although these procedures will continue to be required for very heavily contaminated sites, biotechnology offers more benign and environmentally sustainable remediation systems for less contaminated sites. Application of bioremediation processes results in degradation of the pollutant organics to non-toxic, stable end-products, without adverse impact on terrestrial or atmospheric environments. Use of GMOs with designed abilities to degrade key pollutants will enhance the potential application of bioremediation and should be confined to ex situ, rather than to in situ, applications.

5.7 Genetic Testing

Definitions

Between 2% and 5% of all live born infants have genetic disorders or congenital malformations. Genetic disorders are inherited in two main ways. In dominant diseases, mutation of the copy of the gene inherited from either the father or the mother is sufficient to lead to the development of the disease (examples include Huntington’s disease and inherited breast cancer). In a recessive genetic condition, such as cystic fibrosis (CF) or phenylketonuria (PKU), the copies of the gene inherited from both parents must be damaged for the child to develop the disease. This implies that both parents are carriers for the disease as they have 1 normal copy and 1 mutant copy of the gene. A special type of recessive condition termed X-linked recessive disease (e.g. Haemophilia or Duchenne Muscular Dystrophy) involves a mutated gene on the X chromosome; if the mother is a carrier for the disease (with one mutant and one normal X chromosome), her sons will be at increased risk of developing the disease.

In addition, many common diseases, such as heart disease, diabetes and cancer, have an important genetic component. Increasing awareness of this contribution to disease, allied to the emotional health and economic burden on patients, their families and the community have led to an increasing demand for clinical genetic services.

Genetic testing is a multidisciplinary area, involving a range of medical, scientific and counselling specialities including general practitioners, clinicians, clinical geneticists, molecular biologists, clinical scientists, nurse practitioners and genetic counsellors. The technical part of the genetic testing procedure, which will be referred to in this section as the gene test, chromosome test or DNA test where appropriate, involves the use of either chromosomal analysis or DNA analysis. Chromosomal analysis (often called karyotyping) allows the entire set of chromosomes of an individual to be looked at in a single test and permits detection of relatively large changes in our genetic make up – e.g. the presence of an extra chromosome 21 (termed trisomy 21 as seen in Down’s syndrome). DNA analysis allows the fine structure of specific genes on these chromosomes to be examined, permitting determination of the presence of an abnormal gene in an individual’s genetic blueprint. Using DNA analysis, it is possible to detect a mutation even if it only affects a single building block (termed a base) of a gene.

However, although the technology has made it possible to perform genetic testing in many countries throughout the world, it is important to stress that genetic testing must involve pre and post counselling visits, education of the community (both medical and lay) as well as the taking of a blood sample and performing the test. It is also crucial that non directive counselling is performed such that the final decision to take or not take a genetic test is made by the patient and is not influenced unduly by an over zealous clinician.

Originally genetic testing referred to diseases that were caused solely by a defect or mutation in a single gene giving rise to the disease or making an individual a carrier for the disease. Increasingly this definition is broadening to include gene testing for multifactorial diseases, such as cardiovascular disease where a gene defect may place an individual at increased risk of developing the disease, but where factors such as diet or the environment may also play a role. In addition, karyotyping and DNA testing are very important both in the diagnosis and prognosis of leukaemia and other cancers.

Genetic Testing for Single Gene Disorders

The advances in the application of molecular biology in the health service has led to an increase in the number of genetic tests that are now available. However, it is important to stress that each disease should be considered separately in relation to whether a genetic test best serves the need of the patient, whether it be to aid diagnosis, prognosis or reproductive choices. While technical advances have meant that taking the blood sample and performing the gene test are now routine procedures, the development of a new gene test should not be considered in isolation. Below are some examples of tests that have been or are being developed that show clear benefit to the community.

Genetic testing has, in reality, been performed for many years – a good example is the case of PKU, a deficiency in an enzyme that metabolises phenyalanine, an amino acid which we use as a building block to construct the various proteins and enzymes our body needs. High concentrations of phenylalanine lead to mental retardation, seizures and eczema. Even before DNA testing procedures had been developed, a biochemical test could be performed to determine this deficiency at birth. Community screening programmes are active world-wide involving taking a drop of blood from the heel of an infant and placing it on a card (a Guthrie card) for analysis. Children with the disorder simply need to limit their intake of phenylalanine in their diet to correct the disease. Thus, genetic testing of this and other enzyme deficiency disorders is crucial to designing simple approaches to prevention of the disease symptoms.

Tay-Sachs Disease (TSD) is a recessive, progressive, and ultimately fatal neurodegenerative disorder. Within the last 30 years, the discovery of the cause of the disease (hexosaminidase enzyme deficiency), allied to cloning of the HEXA gene and identification of more than 80 associated TSD-causing mutations, has permitted molecular diagnosis and determination of carrier status in many instances. TSD was the first genetic condition for which community-based screening for carrier detection was implemented. As such, the TSD experience can be viewed as a prototypic effort for public education, carrier testing, and reproductive counselling for avoidance of fatal childhood disease. The outcome of TSD screening over the last 28 years offers convincing evidence that such an effort can dramatically reduce incidence of the disease. Similar studies have been performed for ß thalassaemia, particularly in Mediterranean populations, and the outcome has also been a positive one, reducing the incidence and clinical and economic burden of this disease in the community.

Hereditary Haemochromatosis (HH) is a common iron overload disorder (with a population prevalence of 0.3%-0.8%). It is a common cause of preventable liver, heart, joint, and endocrine disease. An accurate HH diagnosis demands both a high index of suspicion and direct laboratory demonstration of elevated iron parameters. The substantial public health burden of HH as a common, deadly, detectable, and treatable chronic disease has led the College of American

Pathologists to recommend that “systematic screening for haemochromatosis is warranted for all persons over the age of 20 years.” The recent discovery that most HH cases are the result of a single mutation within a transferrin-receptor binding protein (HFE) has given rise to diagnostic tests for the DNA-based detection of this pathologic mutation. This test can now be used, not only to confirm the diagnosis of HH in those with symptomatic disease, but also and perhaps more importantly, to detect those with presymptomatic iron overload in whom future disease manifestations may be prevented with phlebotomy therapy. Thus, genetic testing for this disorder can aid in clinical diagnosis and management of this common genetic disease.

Genetic Testing for Inherited Cancer Susceptibility

Recent studies have indicated that there are inherited forms of various types of cancer, including breast cancer, ovarian cancer and colon cancer. Although these cancers only collectively account for 5-10% of all cancers, inherited breast and colon cancer have higher frequencies in the population than other common single gene disorders – thus a large group of people are at risk of developing inherited cancer. The study of cancer-prone families is a powerful approach to cancer control, particularly when the germ-line mutation is identified in the family and individuals at high risk can be tested, once they provide informed consent, and receive DNA-based genetic counselling. Discovery of the germ-line mutation provides an opportunity to predict patients’ lifetime risk for cancer and, in combination with current therapeutic advances, can help to save lives. There is also a huge demand from families with an increased incidence of inherited cancers for genetic testing and genetic counselling to be available. Motivations for genetic testing include the following: to know if more screening tests are needed, to learn if one’s children are at risk and to be reassured. Barriers to testing included concerns about insurance, test accuracy and how one’s family would react emotionally.

Hereditary breast cancer accounts for 5-10 per cent of all breast cancer cases. About 90 per cent of hereditary breast cancers involve mutation of the BRCA1 and/or BRCA2 genes. Risk estimation is the most important clinical implication. Management options for the high-risk mutation carriers include cancer surveillance and preventative strategies (prophylactic surgery or chemoprevention). Despite inadequate knowledge about the genetic predisposition to breast cancer and its clinical implications, the demand for genetic testing is likely to expand rapidly. In addition to risk estimation, cancer surveillance and preventative strategies, gene therapy may offer a new and theoretically attractive approach to breast cancer management. However, there are a significant number of patients for whom genetic testing may not provide any benefit, as treatment strategies may not be effective or may not be seen as a viable option from the patient’s point of view and so genetic testing should be considered on an individual basis.

In hereditary colon cancer, several studies have indicated that those who sought counselling overestimated their risk for inheriting the mutation, showed a high rate of interest in prophylactic surgery, and were greatly concerned about insurance discrimination. Knowledge about the disease, its molecular genetic diagnosis, surveillance and management opportunities, and genetic counselling implications is still emerging, all in the face of a greater need for physician education regarding all facets of hereditary cancer.

Genetic Testing for Acquired Cancers

The case for genetic testing for acquired cancers is probably less controversial, particularly in the case of leukaemia, where the use of chromosomal or DNA analysis allows easier diagnosis of certain forms of leukaemia and increases our understanding of the mechanism of development of the disease which may help us to develop new therapies. A good example of this is acute promyelocytic leukaemia, where over 98% of patients have an acquired genetic change (called a translocation) involving chromosomes 15 and 17 at diagnosis. One of the genes that is mutated is the retinoic acid receptor gene. Knowledge of this abnormality in a patient immediately allows a clinical decision to be made – clinical remission (reduction of the leukaemia “load”) in these patients can be induced by treatment with retinoic acid. Thus, direct knowledge of the acquired genetic abnormality allows the appropriate therapy to be commenced. The burgeoning influence of chromosomal and DNA analysis in leukaemia health care can be judged by the recent statement from the Medical Research Council in the UK that molecular analysis is the single most important parameter in assessing prognosis.

Genetic Testing for Multifactorial Disorders

Coronary artery disease (CAD) has a strong genetic component, but is also greatly influenced by environmental factors such as diet and smoking, and disorders such as diabetes mellitus and hypertension. In familial hypercholesterolaemia (FH), risk of early CAD is considerably increased by the mutation of a single gene, and genetic testing may be appropriate. We already know that the interaction between environment and particular genotypes may amplify the effect of a particular genotype (e.g. the increased risk of heart disease in patients who smoke and have particular genotypes for certain haemostatic genes). However, for many common diseases we have very little knowledge of how changes in single genes will influence the disease and the response to drugs and very large studies are required to try to tease out these complex relationships.

Issues and Controversies in Genetic Testing

Genetics and Insurance

Questions regarding insurance companies’ access to and use of genetic test results and genetic information have been raised since the advent of the Human Genome Project. The ability to place applicants of similar risks in groups, a process known as underwriting, is critical to the availability and affordability of individually underwritten life, disability income, and long-term care insurance. The availability of presymptomatic and predisposition genetic testing has spawned the need for legislation prohibiting health insurance discrimination on the basis of genetic information. Legislation should be enacted in order to prevent health insurance companies from denying coverage or setting insurance rates on the basis of genetic information. It should also protect the privacy of genetic information and prohibit performance of genetic tests without specific informed consent.

One of the main questions is whether the use of genetic tests and genetic information by life insurance companies should differ from the use of routine medical information. These issues are particularly complex and, in diseases such as Huntington’s disease and Alzheimer’s Disease (AD) where long-term care may be needed, the issues surrounding predictive genetic testing and the use of test results in determining insurance premiums and eligibility are of great concern to patients, clinicians, insurers, ethicists, and patient advocate groups. We must avoid any possibility of genetic discrimination, particularly in presymptomatic persons who test positive for diseases such as Huntington’s disease.

Genetics and Privacy

One of the issues in relation to privacy that is particular to genetic testing is the dilemma of the doctor in keeping a patient’s genetic information confidential as weighed against third parties’ needs to know genetic information regarding their family members. This is a difficult issue to which there are no simple answers. Equally important is the issue of informed consent. An important caveat in relation to genetic testing relates to the large number of families who have participated in research studies in order to help our understanding of how diseases develop. Ireland is a particularly good example in this regard, with close interaction between scientists, patient support groups and the patients and their families. It is important that the strong bond that exists should not be compromised by issues of insurance and privacy and that patients should be adequately protected in this regard.

Community Screening

The increasing availability of DNA-based diagnostic tests has raised issues about whether these should be applied to the population at large in order to identify, treat or prevent a range of diseases. DNA tests raise concerns in the community for several reasons. There is the possibility of stigmatisation and discrimination between those who test positive and those who do not. High-risk individuals may be identified for whom no proven effective intervention is possible, or conversely may test “positive” for a disease that does not eventuate. Controversy concerning prenatal diagnosis and termination of affected pregnancies may arise. It is important that the community itself should be actively involved in evaluating these issues. This allows the collective implications of testing to be evaluated by all interested parties. How genetic screening is socially constructed using a community’s existing dichotomy may be central to its success.

The ability to test for mutations in cystic fibrosis (CF) patients at the molecular level has already improved the diagnosis of symptomatic patients and expanded the reproductive options of family members of CF patients. The same technology also holds promise of identifying asymptomatic carriers and at-risk couples without family history in the general population. However, a number of key issues need to be addressed before a widespread national screening programme can be put into practice. These include the target population to be offered testing (the entire population vs. high-risk ethnic groups), the optimal testing technology, appropriate standards for laboratory quality assurance, and the development of sufficient educational materials and genetic counselling resources for test delivery, reporting, and interpretation. The answers to these questions will be relevant not only to CF testing but also to many other large-scale molecular genetic screening programmes being considered in the future.

Commercial Gene Testing

Commercial gene tests are currently available in many countries and the range of tests offered is likely to increase. As already discussed, genetic testing also brings its own unique problems. Commercial ventures may do little to resolve these and adequate safeguards are needed to ensure that clients undergoing testing are not disadvantaged. In the US there are private companies which are attempting to provide patients with results of gene testing without any counselling or any clinical context and this should be avoided. The availability of gene tests can only serve to heighten public awareness of the relevance of genetics to health care, and there is likely to be an increased demand for information and advice from healthcare professionals before, and following, testing. However, for many individuals, increased knowledge about their genes will present ethical dilemmas which are difficult to resolve. There are also wider ethical issues which concern the use of genetic information by insurers and employers and which concern ownership and access to genetic test data. Provision of information in relation to genetic testing is very important and a web based system that would allow both access to the information and questioning of the issues involved could be a very important resource.

Education and Genetic Testing

Technical advances in genetic testing in the absence of effective treatment have presented the health profession with major ethical challenges. A compelling need exists for adequate education about medical genetics to raise the “literacy” rate among health professionals. As numerous new gene tests are introduced into clinical practice, patients have a growing need for accurate and comprehensive information about the risks and benefits of gene testing. However, in the changing healthcare environment, it is not clear who will provide such information because genetic counsellors are scarce and their services are not widely utilised, and primary care providers lack expertise in genetics and are already over-burdened. One approach that may assist is the use of interactive computers which may help fill the information gap if used appropriately with pre and post counselling sessions. One cannot overemphasise the importance of educating patients about the potential risks, benefits and limitations of genetic testing, with particular emphasis on the possibility of adverse psychological effects and implications for health insurance. Health professionals need to be aware of the technical and ethical implications of these new methods of testing, as well as the complexities in test interpretation, as molecular approaches are increasingly integrated into medical practice.

Conclusion

Genetic testing is currently used to provide prenatal or postnatal diagnosis for a wide range of single gene disorders including inherited cancer syndromes. The meaning of the term needs to be vastly broadened to include the uses of genetic information in mainstream medicine for common multifactorial diseases. Widespread genetic testing must be supported by adequate genetic counselling and by education of healthcare professionals in order to ensure appropriate application of this information for the benefit of patients and their families. Molecular testing raises a number of complex ethical issues, including those associated with prenatal or presymptomatic diagnosis. In addition, there are concerns about informed consent, privacy, genetic discrimination and insurance.

16 Eurobarometer 52.1, “The Europeans and Biotechnology”. European Commission, March 2000.
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17 Gebhard and Smalla (1998). Applied and Environmental Microbiology 64, 1550-1554.
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18 Droge et al. (1998). Journal of Biotechnology 64, 75-90.
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19 Eurobarometer 52.1, “The Europeans and Biotechnology”. European Commission, March 2000.
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20 Focus on Future Issues of Biotechnology (1999), published by Cambridge Biomedical Consultants, Oude Delft, The Netherlands.
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21 Food Safety Authority of Ireland, “Food Safety and Genetically Modified Foods”.
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22 Food Safety Authority of Ireland, “Food Safety and Genetically Modified Foods”.
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