It is perhaps not fair to expect a world with two faces to respond to this new atrocity with honor and honesty. This is why we should seek support and mercy from the One who is the ultimate source of all power and love. We are only as powerful as the length of our essays in this periodical. Thus, we call on the tyrants to stop their cruelties, for they should know that whatever the reasons they have committed them, it will not bring happiness. Happiness comes with virtuousness! We ask these leaders: who is your guide? Do not be mistaken by the fact that these tyrants happen to be in Muslim countries – this does not qualify them to be the rightful followers of the Prophet Muhammad, peace be upon him, for the Prophet, as described in the lead article “was utterly virtuous and contentedly happy. He … never, not even once, consented to anything that was not approved by the Exalted Creator. He was … never unfair and never acted unjustly to anyone. … he never preferred any worldly flavor to virtuousness. He … did not, not even once, fall into hesitation when distinguishing good from bad.” We hope these tyrants are brought to their senses as soon as possible, so that we are saved from our failure to fulfill our basic human responsibilities to stand up for life and dignity. In the meantime, we seek guidance and hope in the Almighty, because ultimately, He is the one with the power to bring these events under control. As we are so often reminded, our human capabilities are quite limited.

The so-called split between science and religion has led us to view life through a binocular with a rather short range. It’s a low definition, black & white range. We thought we were what our genes imposed on us; we believed that natural way would be to let that design unleash itself as genetically ordained. Is it truly so? Are we really nothing more than genetically engineered? Or are there other factors that are involved in making us who we are?

In this issue, “Are Genes the Source of Behavioral Disorders?” explores these questions in a cross-reading between what our biological structure prescribes, vis-à-vis other factors like our culture, parents, education, etc. According to this article “… each child is born with different inclinations and threshold values that are determined genetically and hormonally for each of his or her possible characters and behaviors. These potential inclinations and threshold values can surface depending on internal and external stimuli and educational styles.” So, we are not only what we eat or what we know; we become what we are as a result of a combination of things, some of which we can control, and others which we are born with.

“Why Do We Turn Over During Sleep?” is another article about a daily blessing that is out of our control but is for the good of our health. If we always stay in the same position, sleeping for a regular six to eight hours can cause a disruption in blood circulation, resulting in a pressure ulcer. Therefore, our body is blessed with a defense mechanism in which our position changes, consciously or subconsciously, so that skin integrity is not disrupted.

“Who Owns This Body?” is another contribution on the same theme. The author challenges the belief that we control our bodies, and that no one, not even the One who created us, can impose on our bodies what to do and what not to do. The author gives plenty of examples to show that there is so much happening in our body without our noticing it, that it is nonsensical to claim full ownership over it.

Genetic engineering is one of the fastest developing fields of science. It continues to impact our lives in many ways: the Green Revolution, the quest for perfect animal stock, disease treatment, or human reproduction. But success also has brought concerns. Plants have become insect resistant and also more toxic. Genetically engineered cattle produce more milk but have mutated and overgrown. When scientists opened the window for asexual human reproduction, life became a commodity that could be produced in a culture dish.

And it all started when a monk experimented with some sweet peas…

From Mendel to Dolly

Modern genetic engineering dates back to 1865, when the Austrian monk Gregor Mendel performed a series of experiments with sweet pea plants. These experiments led to changes in the plants’ genetic construction. Genetic engineering, also known as bioengineering or recombinant DNA technology, is a general term referring to any alteration of an organism’s genes in order to make them produce new substances or perform new functions.(1) During the following years, these little experiments developed into a new field. The genes of plants and small-sized organisms were altered through crossing, but other than that research was limited.

In the 1930s, industrial corporations like America’s Rockefeller Foundation or, 20 years later, Germany’s Volkswagen Group (VW), discovered a different approach to raise economic efficiency. At the same time, motives of social control and surveillance directed the Rockefeller Foundation’s interest in the human body to the individual and the collective levels.(2) The Rockefeller Foundation outlined its rationale for supporting genetic research as follows: For the last 100 years physics and chemistry have reigned supreme, and the question of human behavior had been neglected. The new goal was to accomplish social control through understanding and knowledge of the very basic elements of the human body.(3) With the promise of benefit for their own corporations, they started sponsoring this new subfield of biology. The National Institutes of Health, private corporations, institutes, and universities established research laboratories. The idea was that if more actors and institutions shared and exchanged knowledge, the more molecular biology’s narration of life would be consolidated, disseminated, and legitimized.(4) 

Soon discoveries were reported from the science frontier. In 1953, M. Wilkins, F. Crick, and J. Watson discovered DNA’s double helix model while working at the University of Cambridge in England. In 1962, they received the Nobel Prize for their discovery. In 1968 Nirenberg, Khorana and Holley received a Nobel Prize for their interpretation of the genetic code and its function in protein synthesis.(5) 

The first frogs were cloned in 1970. In other words, an artificial copy of their embryo was produced. Soon this fast developing field of biology turned into a new industrial sphere. In 1980, industrial biotechnology emerged after the Supreme Court case of Diamond vs. Chakrabarty. In this case, Chakrabarty engineered and wanted to patent a certain kind of organism. After his request was denied, he went to court and received a favorable ruling. This decision led to the establishment of copyrights for living organisms, which ultimately industrialized the field. Producing and patenting new organisms were two crucial factors in the biotech industry’s development. Consider Steen Willadsen, who cloned the first sheep in 1984 from an embryo.(6) One year later, he mass-produced prize cattle embryos for Grenada Genetics in order to raise a perfect stock.(7) However, that project soon was stopped because of the cloned cattle’s high and death rates and abnormal behavior.

Since the biologic make-up of many mammals had been unveiled, scientists now had a new goal: exploring the human being. Therefore the U.S. Department of Energy launched the human genome project. Soon biotech giants like Celera and many private institutions got into the race. Their goal was to map the entire human genome in order to identify and eliminate disease-causing genes. This project raised certain concerns about what would be done with an individual’s DNA information, who could access it (e.g., insurance companies and employers), and genetic discrimination.

The first human embryos were cloned in 1993. Four years, later the whole world got to meet Dolly, the first sheep cloned from an adult cell. This was an important development, for it opened the door to asexual reproduction. But despite the great enthusiasm with this achievement, some people started wondering about possible dangers. Finally in June 2000, Bill Clinton announced the completion of the human genone project.

Applications and drawbacks

Genetic engineering has penetrated into various parts of our life. Agriculture has seen a Green Revolution. Herbicide-resistant plants were engineered to have built-in pesticide resistance and to convert nitrogen directly from the soil. By April 2002, the approximately 50,000 rice genes had been discovered. Scientists already are working on ways to alter rice, the main food of the world’s population, so that it will be more nutritious and resistant. Insects are being engineered to attack crop predators. Researchers are growing agricultural products in the laboratory using genetically altered bacteria. A major commercial role for genetically engineered plants as chemical factories is also envisioned, such as organic plastics.

Some drawbacks of this revolution are increased toxins and diseases, which are causing the resulting organisms to become resistant to antibiotics. Increased toxins in plants were designed to make insect-resistant plants. Nuclear physicist Dr. John Hagerlin testified in Washington, DC, at the Food and Drug Administration’s (FDA) public hearing that increased toxins trigger unanticipated allergic reactions. The resulting gene pollution threatens the environment, for it breaks down genetic barriers put in place by Nature.(8)

Industrial mistakes in production or insufficient research in engineered food ingredients also can cause serious problems. The Tryptophan food supplement, an amino acid marketed as a natural tranquilizer and sleeping pill, was mass-produced from genetically altered bacteria. It killed 37 persons and permanently disabled over 1,500 others with an incurable nervous system condition known as eosinophilia myalgia syndrome (EMS).(9) When these technologies were applied to livestock, farmers first were pleased that the engineered cattle produced more milk, grew faster, and yielded more meat. However, cases of mutation and rampant overgrowth have caused scientists to reevaluate the effectiveness of these procedures.

Another important issue is inserting human genes in animals. What percent of human genes does an organism have to contain before it is considered human? If humans have a special ethical status, does the presence of human genes in an organism change its ethical status? What about a genetically engineered mouse that produces a human sperm that is then used to conceive a human child?(10) Or a pig that contains human genes in order to grow organs that can be transplanted to humans?(11)

It is shocking that the FDA issued guidelines in September 1996 that allow animal-to-human transplants, even though a group of 44 top virologists, primate researchers, and AIDS specialists, opposed it. They attacked the FDA guidelines, saying that based on knowledge of past cross-species transmissions (e.g., AIDS, Herpes B, Ebola, and other viruses), using animals was not adequately justified for use in a handful of patients. Vast numbers of people could be injured or even killed if a new infectious agent were to be transmitted.(12) The FDA puts the responsibility for health and safety on local hospitals and medical review boards.

Recombinant DNA technology also has been applied directly to the human body. After mapping the entire genome, scientists discovered some disease-causing genes. They are now working to isolate those genes and develop molecular-level treatments. Although curing Alzheimers, nuscular dystrophy, and many other inherited diseases would make patients happy, unexpected results may occur. When applying gene therapy, a one-to-one correspondence between the gene and its function is assumed. Since genes interact in a horizontal manner, as scientists have shown, introducing a new gene could have unforeseen effects.(13)

Genetic manipulation in human beings always encompasses the possibility of designer genes that manipulate a child’s appearance, IQ, or behavior. According to a March of Dimes survey, 40 percent of Americans would use gene therapy to enhance their children’s looks or intelligence. Even picking your child’s gender has become a question of money. A Fairfax, Virginia-based genetics and in-vitro fertilization institute offers family balancing for approximately $3,000. Known as microsort, the male sperm is separated from the female one. In 2001, the institute treated around 60 couples a month and planned to double its production. Fortune Magazine calculated that the microsort market could be worth $200 million.(14)

There is also talk that people could be exploited as producers of certain substances. For example, a biotech corporation applied to the European Patent Office for a patent on a so-called pharm woman. The idea was to genetically alter women so that their breast milk would contain specialized pharmaceuticals.(15)

Related debates

There are many other largely debated topics in this field, but the most controversial one of all is human cloning life. This is divided into therapeutic cloning and reproductive cloning.

In therapeutic cloning, scientists produce embryos in culture dishes to harvest their stem cells. These then are used in further research, the long-term goal of which is to produce replacement organisms. Stem cells are undifferentiated and primitive cells that can be found in embryos as well as in an adult body.(16) Researchers intend to isolate stem cells so they can serve as a starter stock for growing replacement nerve, muscle and other tissue that might one day be used to treat patients with various diseases.(17) Even though this procedure sounds very promising, we should not overlook the fact that embryos are mass-produced to harvest stem cells. Once these have been isolated, the embryo becomes useless and disposable. The ethics of this procedure are questionable, since stem cells also could be harvested from an adult human body.

Reproductive cloning intends to implant such a cloned embryo into a woman’s uterus. Although this procedure is not safe for either the mother or the child, Severino Antinori announced that he and his team will soon produce the first cloned child. The Whitehead Institute of Biomedical Research revealed that cloned mice possess subtle genetic defects that could eventually wreak havoc on the animals system. This means that even though a cloned child might appear completely normal at birth, it has to expect serious health problems later in life.(18)

There also are potential psychological risks for a cloned child. Dr. Thomas Murray worries about the child’s self-identity problem once he/she finds out that he/she is a clone and how he/she was conceived.(19) George Johnson, a professor at Washington University, opposes cloning because genetic variation is the chief defense our species has against an uncertain future. If we strip ourselves of it even partially, it is to endanger our species.

Conclusion

Recombinant DNA technology faces our society with problems unique not only in the history of science but also life on the Earth as well as legal approaches towards them. It places in human hands the capacity to redesign living organisms. It presents probably the largest ethical problem science has ever had to face. Our morality up to now has been to go ahead without restrictions to learn what we can about nature. Reconstructing nature was not part of the bargain. Going ahead in this direction may not be only unwise but also dangerous. Potentially it could breed new animal and plant diseases, new sources of cancer and novel epidemics.(20)

Since creation is in a perfect balance, interventions might have unforeseen effects. A book must be written by an author, a picture must be painted by an artist, and a poem must be written by a poet. Each piece of art has an artist who has an encompassing knowledge of his/her creation. If we do not understand that nature is a perfectly composed book, our writings will be no more than scribbles between the lines.

Footnotes

1. http://209.52.56.28/lexicon/g.html.
2. Lily E. Kay, The Molecular Vision of Life: Caltech, the Rockefeller Foundation, and the Rise of the New Biology (Oxford: Oxford University Press, 1993), 26.
3. Herbert Gottweiss, Governing Molecules: The Discursive Politics of Genetic Engineering in Europe and the US (Cambridge MA: The MIT Press, 1998), 42.
4. Ibid., 46.
5. www.nobel.se/medicine/laureates/1968/index.html.
6. www.dartmouth.edu/artsci/courses/coco25/Cloning/The_History_of_Cloning.html.
7. http://library.thinkquest.org/24355/data/details/1985.html?tqskip1=1&tqtime=0508.
8. www.netlink.de/gen/hagelin.html.
9. www.psrast.org/jftrypt.htm.
10. Surrogate Fathers, New Scientist (31 Jan. 1998).
11. Robert Pool, Saviors, Discover, (May 1998): 53-57. (special issue.)
12. IP/BiodivNews, 1-24-97 or http://online.sfsu.edu/~rone/GE%20Essays/Redigning.htm#40.
13. Horizontal gene transfer refers to the transfer of genes to unrelated species by infection through viruses, through pieces of genetic material, DNA by being taken up into cells from the environment, or by unusual mating taking place between unrelated species. (Mae-Wan Ho, Genetic Engineering: Dream or Nightmare, 2d rev. [Continuum Pub Group: 2000),
14. The Economist (14 Apr. 2001): 22.
15. Andrew Kimbrell, The Human Body Shop: The Engineering and Marketing of Life (New York: Harper Collins, 1994), 191.
16. Popular Science (Jan. 2002): 58.
17. Scientific American (Jan. 2002): 45.
18. Gunjan Sinha, Popular Science (Jan. 2002)
19. Thomas Murray, Talk of the Nation broadcast, 24 Feb. 1997.
20. George Wald, The Case Against Genetic Engineering, in The Recombinant DNA Debate, eds. David A. Jackson and Stephen P. Stich (Prentice Hall College Div: 1979), 127-28.

The movie might be a fad, or a nine days’ wonder, simply another Spielberg special, like Jaws or E.T. However, this time the messages that the movie addresses have far-reaching consequences for mankind.

Thanks to Jurassic Park, our attention has been drawn to the recent achievements made in molecular biology and we have the opportunity to ponder how genetic engineering, in the hands of scientists who are apparently unrestrained by moral and ethical values, could threaten the ecological equilibrium of the planet and our very survival.

Let us consider the scientific advantages and ethical disadvantages of the advance of genetic engineering, by taking a look at the various applications of this knowledge in the modern world.

In Jurassic Park, John Hammond, played by Richard Attenborough, inspired by motives of forwarding the causes of science and making a profit, undertakes a scheme to clone living copies of dinosaurs from DNA extracted from fossilised, blood-sucking insects, preserved in amber. The origin of this idea was first proposed by George Poinar and his team at California University, Berkeley. In the last twenty years there have been many scientists working on the extraction of DNA from fossilized remains and the notion of obtaining dinosaur DNA in this way became feasible. Ironically, on the eve of the release of Jurassic Park, Poinar announced that his group had, in fact, extracted the first samples of genetic material from the age of the dinosaur. Using liquid nitrogen to crack open a sample of amber, DNA had been obtained from a weevil trapped 120 million years ago. Using gene-amplifying techniques, scientists are now able to make billions of copies of any piece of DNA.

I would like to draw your attention to two aspects of these scientific endeavors; firstly to the religious dimension and secondly to the wider ethical considerations of genetic engineering.

We must first ponder the notion that if it is possible for mortal human beings to produce synthetic RNA, one of the master-molecules in the nuclei of all cells, or to reproduce extinct animals by the retrieval of their DNA, surely it is possible for God, the All-Mighty, to recreate us from our bones on the Day of the Resurrection.

There are, of course, more secular ethical considerations in the application of genetic engineering. Today, scientists are experimenting with gene sequences and seem to have the ability to switch particular genetic codes on and off. By this means, science is on the brink of producing hybrid organisms in vitro. One recent experiment reported in The Economist (18th September 1993: pp.119-20) described how scientists were able to change the function of developing organs in four-hour-old fly embryos. One claim made recently is that the difference between man and chimpanzees is a few critical genes affecting intelligence. Are we to allow scientists, once these genes have been isolated, to create a hybrid intelligence? Are we ready to have these hybrid creatures living in our midst?

Will the Beast (Dabbah) mentioned in the Qur’an (al Naml, 27.82) be the result of such unrestrained scientific enquiry? What are the moral, ethical and religious implications of these advances?

When recent experiments on human cloning were publicized people seemed to worry, and worry deeply, about the horrific implications of duplicating a human embryo. This experiment is not the Jurassic Park-type cloning many might imagine. The worrying thing is that such technology really could pave the road to embryo factories to selling foetuses, freezing cloned foetuses for ‘spare organs’ that might be needed, or to be giving birth to genetically the same child at intervals, even to ‘maturing’ a twin cloned and stored for later use. According to Time’s survey 63% of people asked said human cloning is against God’s will; 90% of women stated that they would not be interested in cloning an embryo: a 58% said it is morally wrong (Time, 8 November 1993, pp.63-8).

In Jurassic Park, chaos theoretician Ian Malcolm, played by Jeff Goldblum, insists that what God has put asunder, no man should join together. Man should not interfere with the order of nature ordained by God and Malcolm says: ‘God created dinosaurs, God destroyed dinosaurs. God created Man, Man created dinosaurs’. Viewed in this perspective, can we foresee the consequences of interfering with this divine order, created by Allah in perfect balance? (al-Rahman, 55.8).

Today, genetic engineering is becoming a commercial enterprise in the hands of avaricious entrepreneurs and ethical considerations are being subverted by the desire for profit. The same technology is also being investigated to make tailor-made human organs, for transplantation into human patients. The specificity of these engineered organs would, in principle, avoid problems of rejection, as well as the practical and moral problems associated with human donors. This sounds good, but are we allowing ourselves, unhampered by moral considerations, to pave the way to a greater calamity?

Great advances have also been made in the field of agricultural genetics, with scientists trying to find answers to the problems of feeding a spiralling world population and of growing crops and raising cattle on poor soil or in adverse weather conditions. The Malthusian nightmare of populations being decimated by starvation has, to some extent, been averted in this century, although most of the benefits of these advances have been felt in the West where intensive farming of hardy crops and animal breeds have produced huge surpluses of food. For example, bovine growth hormone can be injected into dairy herds to give higher milk-yields and hybridization of crops has been used to produce strains which will grow in areas thought to have been useless for large-scale farming.

Genetic engineering in the field of producing vigorous or hardy varieties and breeds has signalled a new departure. Instead of the long, hit and miss processes of traditional hybridization, scientists are now able to isolate and transfer genetic material to improve the vigor of an organism or to increase its resistance to disease, insect damage or weed killers. Plants have been produced which fix their own nitrogen, as do natural legumes, and strains of bamboo have been reproduced which grow faster than the ‘natural’ varieties. All of this progress seems to suggest that yet another watershed has been reached in the realms of technology and productivity, which might offer benefits to all of mankind.

There is, however, another side to this coin. For example, hogs which have been treated with growth hormone are subject to gastric ulcers, arthritis, dermatitis and other diseases, making their already shortened lives a pain-ridden misery, and producing animals possibly unfit for human consumption. In Arable farming too, the production of herbicide-resistant crops encourages the indiscriminate spraying of chemicals on the land, increasing pollution of land and waterways. The agro-chemical companies are simply creating a ‘treadmill’ whereby new formulas are constantly needed to combat the new mutants of resistant pests.

Another environmental concern is that biotech agriculture will encourage the evasion of fundamental ecological reforms. If crop species can he easily bred to thrive in inhospitable conditions, farmers may fail to see the need to prevent environmental damage and simply wait for the scientists to engineer new crops or beasts to suit the new conditions. Would fish, genetically modified to flourish in acidified lakes, undercut the determination to clean up the air and water? Perhaps scientists should be concentrating more on the fundamental problems of the environment, rather than inventing palliatives to deal with the ravages of mankind. Surely it is better, for example, to find ways of conserving the rain forests than to invent ways of recreating their extinct flora and fauna?

Because of the limitless possibilities offered by the application of gene technology, DNA has become a corporate resource which can be patented and owned, designed in the laboratory and used to replace raw materials. This tendency may lead to the monopolization of genetic resources, placing control in the hands of multi-national giants whose main motive is profit, rather than with the people who need to use the technology to live.

Biotechnology will introduce a new era, greatly changing the way we live and the structure of our national economies. Food production in the laboratory will mean that traditional farming jobs will disappear–the EEC have already issued directives setting strict quotas for this type of production (EC Commission Directives 90/219 and 90/220). Consumers will also be directly affected and there is already a growing ‘grass-roots’ opposition to genetically engineered plants and animals. In the United States, for example, there have been moves to boycott such products and some restaurants have refused to serve genetically engineered foodstuffs. On 3rd October, l993, legislation came into force in Chicago obliging all food outlets to label genetically engineered food.

Studies in genetics are not confined to medicine and food production. In 1986, Professor Alec Jeffreys, of Leicester University in England, discovered that DNA is as individual as a finger-print and his research led to the genetic finger-printing techniques now established in forensic science. Samples of DNA taken from body fluids or tissues can provide an unmistakable ‘identity card’ and so assist in the conviction of offenders, particularly in cases of physical violence or sexual assault. DNA recovered from the victims of such crimes is now regarded by the British judicial system as highly reliable evidence and its use in the conviction of suspects is spreading, very rapidly, worldwide.

Even this seemingly overpoweringly beneficial use of genetic science has its dark side. The possibility of creating global genetic databases, with genetic information on all known criminals would appear to be an ideal solution in these times of escalating crime. However, there are issues of civil liberty to be tackled, and there is public resistance to such information being collated, using much the same arguments as have been used to resist the issuing of identity cards. There is also the problem of information held on these databases finding its way into the wrong hands. Again, mankind is faced with moral and ethical questions concerning the use and the abuse of technology.

Further Reading 

• BBC2 SERIES Cracking The Code: The Mouse That Laid The Golden Egg.
• HURREL, M. (1992) ‘Criminals Could Go On To World Blacklist’, The Times, 8 May, p.26.
• KENNEDY, P. (1993) Preparing for the Twenty-First Century, Harper-Collins Publishers, London, pp.65-8l.
• NASH, J. M. (1993) ‘How Did Life Begin?’, Time, 11 October, pp.53-9.
• RICHARD, M. et al. (1993) ‘Archaeology and Genetics: analyzing DNA from skeletal remains’. 25 (1) World Archaeology, pp.18-28
• TEICHMAN, D. L. (1993) Regulation of Recombinant DNA Research: a comparative study, 6 (1) Loyola Los Angeles International & Comparative Law, pp. l-35.
• TRUX, J. (1993) ‘A Case of Unmistakable Identity’, Observer, 13 August.
• WALKER, J. (1990) ‘DNA Profiling and Police Powers’, Criminal Law Review, pp. 479-93.
• TIME, (November 1993) ‘Cloning: Where Do We Draw The Line?’, pp.63-8.

Plant breeding has several other serious limitations for use as a tool to increase disease resistance. There are only a limited number of plant species which are able to cross-fertilize, thus restricting the transfer of potentially useful traits. Moreover, having found useful traits, it is impossible to prevent the co-transfer of undesirable ones, which can take many years to breed out again by back-crossing.

How can genetic engineering be of use in the quest for new answers to the problems of providing plants with the ability to resist disease? The aim of crop plant genetic engineering is to insert a gene (or genes) which improve an existing plant variety whilst retaining the desirable genetic make up of the original plant.

The main tool at the disposal of the scientist is the use of nature’s own genetic engineer, Agro-bacterium tumefaciens. The manipulation of this bacterium’s natural functions has allowed the biologist to transfer many foreign genes into plants. The bacterium is soil-borne and infects plants at the crown, usually through a wound site, causing cancerous growths of proliferating plant cells known as crown gall tumors. This disease in itself is ergonomically important and effects most dicotyledonous plants causing millions of dollars’ worth of damage to plants. In the 1940s, from experimental observations, it was concluded that a factor is transmitted from the invading bacteria to the host plant cell. Further studies demonstrated that the disease is actually the direct result of the transfer of a particular DNA fragment (genes) from the bacterium to the plant cell. In addition to its chromosomal DNA, Agro-bacterium contains a much smaller circular DNA molecule called a Ti (tumor-inducing) plasmodia, of which a small piece, called the T-DNA (Transferred-DNA), is the factor transferred into plant cells (see Figure 1). The T-DNA becomes stably integrated into the plant’s chromosomes, from where it is able to perturb the natural functions of the plant. The T-DNA encodes genes, which, when expressed, bring about the production of new enzymes that are able to alter the hormone balance within the infected cell. This brings about de-differentiation and cell division, leading to proliferation of cells and the formation of tumors. This appears to be of little benefit to the bacterium. However, other genes are also present in the T-DNA which, when expressed, are able to synthesize novel compounds from naturally occurring plant precursors. These novel compounds cannot be metabolized by the plant but are a good source of nutrients for the bacterium.

Mutation analysis of the T-DNA revealed two regions, the left and right borders, which were essential for integration into the chromosome. It was also found that any piece of DNA inserted between these borders was stably inserted into the host chromosome on transformation. Deletion of the genes for tumor formation (Disarmed Ti-Plasmid) were found to have no effect on the transfer efficiency from bacterium to plants. Availability of disarmed Ti-plasmids, tissue culture methods for the regeneration of whole fertile plants from single cells, and marker genes (such as antibiotic resistance) for the selection of transformed cells, have allowed for the production of a whole new range of plants containing foreign genes. Several genes responsible for pathogen and herbicide resistance proteins have been isolated from the bacteria and viruses. These genes have then been inserted into the T-DNA region of Agro-bacterium and introduced into plants, giving rise to insect, virus or herbicide resistant plants.

By using Agro-bacterium as a plant genetic engineer, many crop plants such as the tomato, potato and cucumber have now been engineered for virus resistance. Field tests showed that these genetically modified plants appeared to be highly resistant to viral infections. Similarly genetically-engineered cotton plants have proved to be resistant to insect attack and many herbicides (weed killers).

Another powerful new genetic engineering technique is ‘antigens’ technology, whereby specific gene transcripts are prevented from being translated into proteins. By using antigens technology, it has been possible to produce genetically engineered tomato plants that have a much increased shelf-life. Although many aspects of gene transfer from Agro-bacterium to plants are not fully understood, the use of Agro-bacterium for gene transfer will continue to increase; and it is likely that genetically engineered crops carrying traits for resistance to herbicides, insects and viral diseases will soon reach the market-place.