Second, the resistance genes could be transferred to human or animal pathogens, making them impervious to antibiotics. If transfer were to occur, it could aggravate the already serious health problem of antibiotic-resistant disease organisms. Although unmediated transfers of genetic material from plants to bacteria are highly unlikely, any possibility that they may occur requires careful scrutiny in light of the seriousness of antibiotic resistance.

In addition, the widespread presence of antibiotic-resistance genes in engineered food suggests that as the number of genetically engineered products grows, the effects of antibiotic resistance should be analyzed cumulatively across the food supply.

Production of New Toxins

Many organisms have the ability to produce toxic substances. For plants, such substances help to defend stationary organisms from the many predators in their environment. In some cases, plants contain inactive pathways leading to toxic substances. Addition of new genetic material through genetic engineering could reactivate these inactive pathways or otherwise increase the levels of toxic substances within the plants. This could happen, for example, if the on/off signals associated with the introduced gene were located on the genome in places where they could turn on the previously inactive genes.

Concentration of Toxic Metals

Some of the new genes being added to crops can remove heavy metals like mercury from the soil and concentrate them in the plant tissue. The purpose of creating such crops is to make possible the use of municipal sludge as fertilizer. Sludge contains useful plant nutrients, but often cannot be used as fertilizer because it is contaminated with toxic heavy metals. The idea is to engineer plants to remove and sequester those metals in inedible parts of plants. In a tomato, for example, the metals would be sequestered in the roots; in potatoes in the leaves. Turning on the genes in only some parts of the plants requires the use of genetic on/off switches that turn on only in specific tissues, like leaves.

Such products pose risks of contaminating foods with high levels of toxic metals if the on/off switches are not completely turned off in edible tissues. There are also environmental risks associated with the handling and disposal of the metal-contaminated parts of plants after harvesting.

Enhancement of the Environment for Toxic Fungi

Although for the most part health risks are the result of the genetic material newly added to organisms, it is also possible for the removal of genes and gene products to cause problems. For example, genetic engineering might be used to produce decaffeinated coffee beans by deleting or turning off genes associated with caffeine production. But caffeine helps protect coffee beans against fungi. Beans that are unable to produce caffeine might be coated with fungi, which can produce toxins. Fungal toxins, such as aflatoxin, are potent human toxins that can remain active through processes of food preparation.

No Long-Term Safety Testing

Genetic engineering uses material from organisms that have never been part of the human food supply to change the fundamental nature of the food we eat. Without long-term testing no one knows if these foods are safe.

Decreased Nutritional Value

Transgenic foods may mislead consumers with counterfeit freshness. A luscious-looking, bright red genetically engineered tomato could be several weeks old and of little nutritional worth.

Problems Cannot Be Traced

Without labels, our public health agencies are powerless to trace problems of any kind back to their source. The potential for tragedy is staggering.

Side Effects can Kill

37 people died, 1500 were partially paralyzed, and 5000 more were temporarily disabled by a syndrome that was finally linked to tryptophan made by genetically-engineered bacteria.

Unknown Harms

As with any new technology, the full set of risks associated with genetic engineering have almost certainly not been identified. The ability to imagine what might go wrong with a technology is limited by the currently incomplete understanding of physiology, genetics, and nutrition.

Potential Environmental Harms

Increased Weediness

One way of thinking generally about the environmental harm that genetically engineered plants might do is to consider that they might become weeds. Here, weeds means all plants in places where humans do not want them. The term covers everything from Johnson grass choking crops in fields to kudzu blanketing trees to melaleuca trees invading the Everglades. In each case, the plants are growing unaided by humans in places where they are having unwanted effects. In agriculture, weeds can severely inhibit crop yield. In unmanaged environments, like the Everglades, invading trees can displace natural flora and upset whole ecosystems.

Some weeds result from the accidental introduction of alien plants, but many were the result of purposeful introductions for agricultural and horticultural purposes. Some of the plants intentionally introduced into the United States that have become serious weeds are Johnson grass, multiflora rose, and kudzu. A new combination of traits produced as a result of genetic engineering might enable crops to thrive unaided in the environment in circumstances where they would then be considered new or worse weeds. One example would be a rice plant engineered to be salt-tolerant that escaped cultivation and invaded nearby marine estuaries.

Gene Transfer to Wild or Weedy Relatives

Novel genes placed in crops will not necessarily stay in agricultural fields. If relatives of the altered crops are growing near the field, the new gene can easily move via pollen into those plants. The new traits might confer on wild or weedy relatives of crop plants the ability to thrive in unwanted places, making them weeds as defined above. For example, a gene changing the oil composition of a crop might move into nearby weedy relatives in which the new oil composition would enable the seeds to survive the winter. Overwintering might allow the plant to become a weed or might intensify weedy properties it already possesses.

Change in Herbicide Use Patterns

Crops genetically engineered to be resistant to chemical herbicides are tightly linked to the use of particular chemical pesticides. Adoption of these crops could therefore lead to changes in the mix of chemical herbicides used across the country. To the extent that chemical herbicides differ in their environmental toxicity, these changing patterns could result in greater levels of environmental harm overall. In addition, widespread use of herbicide-tolerant crops could lead to the rapid evolution of resistance to herbicides in weeds, either as a result of increased exposure to the herbicide or as a result of the transfer of the herbicide trait to weedy relatives of crops. Again, since herbicides differ in their environmental harm, loss of some herbicides may be detrimental to the environment overall.

Squandering of Valuable Pest Susceptibility Genes

Many insects contain genes that render them susceptible to pesticides. Often these susceptibility genes predominate in natural populations of insects. These genes are a valuable natural resource because they allow pesticides to remain as effective pest-control tools. The more benign the pesticide, the more valuable the genes that make pests susceptible to it.

Certain genetically engineered crops threaten the continued susceptibility of pests to one of nature's most valuable pesticides: the Bacillus thuringiensis or Bt toxin. These "Bt crops" are genetically engineered to contain a gene for the Bt toxin. Because the crops produce the toxin in most plant tissues throughout the life cycle of the plant, pests are constantly exposed to it. This continuous exposure selects for the rare resistance genes in the pest population and in time will render the Bt pesticide useless, unless specific measures are instituted to avoid the development of such resistance.

Poisoned Wildlife

Addition of foreign genes to plants could also have serious consequences for wildlife in a number of circumstances. For example, engineering crop plants, such as tobacco or rice, to produce plastics or pharmaceuticals could endanger mice or deer who consume crop debris left in the fields after harvesting. Fish that have been engineered to contain metal-sequestering proteins (such fish have been suggested as living pollution clean-up devices) could be harmful if consumed by other fish or raccoons.

Creation of New or Worse Viruses

One of the most common applications of genetic engineering is the production of virus-tolerant crops. Such crops are produced by engineering components of viruses into the plant genomes. For reasons not well understood, plants producing viral components on their own are resistant to subsequent infection by those viruses. Such plants, however, pose other risks of creating new or worse viruses through two mechanisms: recombination and transcapsidation.

Recombination can occur between the plant-produced viral genes and closely related genes of incoming viruses. Such recombination may produce viruses that can infect a wider range of hosts or that may be more virulent than the parent viruses.

Transcapsidation involves the encapsulation of the genetic material of one virus by the plant-produced viral proteins. Such hybrid viruses could transfer viral genetic material to a new host plant that it could not otherwise infect. Except in rare circumstances, this would be a one-time-only effect, because the viral genetic material carries no genes for the foreign proteins within which it was encapsulated and would not be able to produce a second generation of hybrid viruses.

Gene Pollution Cannot Be Cleaned Up

Once genetically engineered organisms, bacteria and viruses are released into the environment it is impossible to contain or recall them.

Unlike chemical or nuclear contamination, negative effects are irreversible.

DNA is actually not well understood.

Yet the biotech companies have already planted millions of acres with genetically engineered crops, and they intend to engineer every crop in the world.

The concerns above arise from an appreciation of the fundamental role DNA plays in life, the gaps in our understanding of it, and the vast scale of application of the little we do know. Even the scientists in the Food and Drug administration have expressed concerns.

Unknown Harms

As with human health risks, it is unlikely that all potential harms to the environment have been identified. Each of the potential harms above is an answer to the question, "Well, what might go wrong?" The answer to that question depends on how well scientists understand the organism and the environment into which it is released. At this point, biology and ecology are too poorly understood to be certain that question has been answered comprehensively.

Any pros?

Certainly, there should be some. Still, most of them are connected with commercial gains for genetic engineering companies. A popular claim, that farmers will benefit, is simply not true. It is just the same thing with consumers. No one is going to feed the poorest with GE products for the famine in many underdeveloped countries is simply the matter of inability to buy food, not lack of it. So today, at the present stage of development, we hardly need GE expanding on food products, needless to say about animal and human cloning. Incidentally, some daydreaming proponents of GE really believe that mankind will not be able to survive without it. According to them, we will certainly have to genetically upgrade ourselves in response to governmental activities. The humans will be able to hibernate – just like some animals – to cover long distances without aging, and, probably, will become immortal…

Still, what about the present need of GE? Where can GE particularly be used now without a threat to the humans and the environment?

So, scientists say that genetic engineering can make it possible to battle disease (cancer, in particular), disfigurement, and other maladies through a series of medical breakthroughs that will be beneficial to the human race. Moreover, cloning will be able to end the extinction of many endangered species. The main question is whether we can trust genetic engineering. The fact is that even genetically changed corn is already killing species.

The recent research showed that pollen from genetically engineered corn plants is toxic to monarch butterflies. Corn plants produce huge quantities of pollen, which dusts the leaves of plants growing near corn fields. Close to half the monarch caterpillars that fed on milkweed leaves dusted with Bt corn pollen died. Surviving caterpillars were about half the size of caterpillars that fed on leaves dusted with pollen from non-engineered corn. Something is wrong with the engineered products – they are different, so we cannot be sure about the effect they will bring about.

So, is the technology trustworthy? I suppose not.

Conclusion

So, do we need it? There are far too many disadvantages of GE and far too many unpredictable things may happen. The humans are amateurs in this area, in fact, they are just like a monkey taught to press PC buttons. We have almost no experience, the technology has not yet evolved enough. I believe, we should wait, otherwise we may give birth to a trouble, which would be impossible to resolve.

References

1. David Heaf ‘Pros and Cons of Genetic Engineering’, 2000, ifgene;

2. Ricarda Steinbrecher, 'From Green to Gene Revolution', The Ecologist,
   Vol 26 No 6;

3. ‘Genetic Engineering Kills Monarch Butterflies’, Nature Magazine, May 19,1999;

4. ‘Who's Afraid of Genetic Engineering?’ The New York Times August 26, 1998;

5. Sara Chamberlain ‘Techno-foods’, August 19, 1999, The New Internationalist;

6. W French Anderson, 'Gene Therapy' in Scientific American, September 1995;

7. Nature Biotechnology Vol 14 May 1996;

8. Andrew Kimbrell 'Breaking the Law of Life' in Resurgence May/June 1997 Issue 182;

9. Jim Hightower ‘What’s for dinner?’, May 29, 2000.

Contents

Introduction 1

What is genetic engineering? 1

Techniques 1

The history of GE 2

Selective breeding and genetic engineering 3

What are the dangers? 3

Fundamental Weaknesses of the Concept 3

Health Hazards 4

Potential Environmental Harms 6

Any pros? 8

Conclusion 9

References 10