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Реферат: Genetic Engineering

                    All that we are is the result of what we have thought
                        For what shall it profit a man, if he shall gain 
                                   the whole world and lose his own soul?
                                                         The Bible


While plant biotechnology has been used for centuries to enhance plants, microorganisms and animals for food, only recently has it allowed for the transfer of genes from one organism to another. Yet there is now a widespread controversy over the harmful and beneficial effects of genetic engineering to which, at this time, there seems to be no concrete solution. The ideas below are expected to bring in a bit of clearance into the topic. Here I’m going to reveal some facts concerning genetic engineering, specially the technology, its weak and strong points (if any). Probably the information brought is a bit too prejudiced, for I’m certainly not in favor of making jokes with nature, but I really tried to find some good things about GE.

What is genetic engineering?

Genetic engineering is a laboratory technique used by scientists to change the DNA of living organisms. DNA is the blueprint for the individuality of an organism. The organism relies upon the information stored in its DNA for the management of every biochemical process. The life, growth and unique features of the organism depend on its DNA. The segments of DNA which have been associated with specific features or functions of an organism are called genes. Molecular biologists have discovered many enzymes which change the structure of DNA in living organisms. Some of these enzymes can cut and join strands of DNA. Using such enzymes, scientists learned to cut specific genes from DNA and to build customized DNA using these genes. They also learned about vectors, strands of DNA such as viruses, which can infect a cell and insert themselves into its DNA. With this knowledge, scientists started to build vectors which incorporated genes of their choosing and used the new vectors to insert these genes into the DNA of living organisms. Genetic engineers believe they can improve the foods we eat by doing this. For example, tomatoes are sensitive to frost. This shortens their growing season. Fish, on the other hand, survive in very cold water. Scientists identified a particular gene which enables a flounder to resist cold and used the technology of genetic engineering to insert this 'anti-freeze' gene into a tomato. This makes it possible to extend the growing season of the tomato. At first glance, this might look exciting to some people. Deeper consideration reveals serious dangers.


There are 4 types of genetic engineering which consist of recombinant engineering, microinjection, electro and chemical poration, and also bioballistics.

r-DNA technology

The first of the 4, recombinant engineering, is also known as r-DNA technology. This technology relies on biological vectors such as plasmids and viruses to carry foreign genes into cells. The plasmids are small circular pieces of genetic material found in bacteria that can cross species boundaries. These circular pieces can be broken, which results with an addition of a new genetic material to the broken plasmids. The plasmids, now joined with the new genetic material, can move across microbial cell boundaries and place the new genetic material next to the bacterium's own genes. After this takes place, the bacteria will then take up the gene and will begin to produce the protein for which the gene codes. In this technique, the viruses also act as vectors. They are infectious particles that contain genetic material to which a new gene can be added. Viruses carry the new gene into a recipient cell driving the process of infecting that cell. However, the viruses can be disabled so that when it carries a new gene into a cell, it cannot make the cell reproduce or make copies of the virus.


The next type of genetic engineering is referred to as microinjection. This technique does not rely on biological vectors, as does r-DNA. It is somewhat of a simple process. It is the injecting of genetic material containing the new gene into the recipient cell. Where the cell is large enough, injection can be done with a fine-tipped glass needle. The injected genes find the host cell genes and incorporate themselves among them.

Electro and chemical poration

This technique is a direct gene transfer involving creating pores or holes in the cell membrane to allow entry of the new genes. If it is done by bathing cells in solutions of special chemicals, then it is referred to as chemical poration. However, if it goes through subjecting cells to a weak electric current, it is called electroporation.

Bio ballistics

This last technique is a projectile method using metal slivers to deliver the genetic material to the interior of the cell. These small slivers, which must be smaller than the diameter of the target cell, are coated with genetic material. The coated slivers are propelled into the cells using a shotgun. After this has been done, a perforated metal plate stops the shell cartridge but still allows the slivers to pass through and into living cells on the other side. Once inside, the genetic material is transported to the nucleus where it is incorporated among host cells.

The history of GE

The concept was first introduced by an Australian monk named Gregor Mendel in the 19th century. His many experiments cemented a foundation for future scientists and for the founding concepts in the study of genetics. Throughout Mendel's life, he was a victim of criticism and ridicule by his fellow monks for his "foolish" experiments. It took 35 years until he was recognized for his experiments and known for the selective breeding process. Mendel's discoveries made scientists wonder how information was transferred from parent to offspring and whether the information could be captured and/or manipulated. James D. Watson and Francis H. C. Crick were curious scientists who later became known as the founding fathers of genetic engineering. Watson and Crick wanted to determine how genetic blueprints are determined and they also proposed that DNA structures are genetic messengers or that chemical compounds of proteins and amino acids all come together as a way to rule out characteristics and traits. These 2 scientists produced a code of DNA and thus answered the question of how characteristics are determined. They also established that DNA are the building blocks of all organisms.

Selective breeding and genetic engineering

Selective breeding and genetic engineering are "both used for the improvement of human society." However, selective breeding is a much longer and more expensive process than genetic engineering. It takes genetic engineering only one generation of offspring to see and study improvement as opposed to selective breeding where many generations are necessary. Therefore, it costs more to observe many generations. Selective breeding is known as the natural way to engineer genes while genetic engineering is more advanced, technical, scientific, complex and is inevitable in out future.

What are the dangers?

Many previous technologies have proved to have adverse effects unexpected by their developers. DDT, for example, turned out to accumulate in fish and thin the shells of fish-eating birds like eagles and ospreys. And chlorofluorocarbons turned out to float into the upper atmosphere and destroy ozone, a chemical that shields the earth from dangerous radiation. What harmful effects might turn out to be associated with the use or release of genetically engineered organisms? This is not an easy question. Being able to answer it depends on understanding complex biological and ecological systems. So far, scientists know of no generic harms associated with genetically engineered organisms. For example, it is not true that all genetically engineered foods are toxic or that all released engineered organisms are likely to proliferate in the environment. But specific engineered organisms may be harmful by virtue of the novel gene combinations they possess. This means that the risks of genetically engineered organisms must be assessed case by case and that these risks can differ greatly from one gene-organism combination to another. So far, scientists have identified a number of ways in which genetically engineered organisms could potentially adversely impact both human health and the environment. Once the potential harms are identified, the question becomes how likely are they to occur. The answer to this question falls into the arena of risk assessment. In addition to posing risks of harm that we can envision and attempt to assess, genetic engineering may also pose risks that we simply do not know enough to identify. The recognition of this possibility does not by itself justify stopping the technology, but does put a substantial burden on those who wish to go forward to demonstrate benefits.

Fundamental Weaknesses of the Concept

Imprecise Technology—A genetic engineer moves genes from one organism to another. A gene can be cut precisely from the DNA of an organism, but the insertion into the DNA of the target organism is basically random. As a consequence, there is a risk that it may disrupt the functioning of other genes essential to the life of that organism. (Bergelson 1998) Side Effects—Genetic engineering is like performing heart surgery with a shovel. Scientists do not yet understand living systems completely enough to perform DNA surgery without creating mutations which could be harmful to the environment and our health. They are experimenting with very delicate, yet powerful forces of nature, without full knowledge of the repercussions. (Washington Times 1997) Widespread Crop Failure—Genetic engineers intend to profit by patenting genetically engineered seeds. This means that, when a farmer plants genetically engineered seeds, all the seeds have identical genetic structure. As a result, if a fungus, a virus, or a pest develops which can attack this particular crop, there could be widespread crop failure. (Robinson 1996) Threatens Our Entire Food Supply—Insects, birds, and wind can carry genetically altered seeds into neighboring fields and beyond. Pollen from transgenic plants can cross-pollinate with genetically natural crops and wild relatives. All crops, organic and non-organic, are vulnerable to contamination from cross-pollinatation. (Emberlin 1999)

Health Hazards

Here are the some examples of the potential adverse effects of genetically engineered organisms may have on human health. Most of these examples are associated with the growth and consumption of genetically engineered crops. Different risks would be associated with genetically engineered animals and, like the risks associated with plants, would depend largely on the new traits introduced into the organism.

New Allergens in the Food Supply


Antibiotic Resistance


Production of New Toxins


Concentration of Toxic Metals


Enhancement of the Environment for Toxic Fungi


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


Unknown Harms


Potential Environmental Harms

Increased Weediness


Gene Transfer to Wild or Weedy Relatives


Change in Herbicide Use Patterns


Squandering of Valuable Pest Susceptibility Genes


Poisoned Wildlife


Creation of New or Worse Viruses


Gene Pollution Cannot Be Cleaned Up


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


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.


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.


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