In terms of agriculture, genetic engineering has already been widely used. Genetically engineered crops are the most typical examples that genetic engineering is handled in the field of agriculture. They are made by artificial way that is transfer genes from other organisms. There are lots of examples about genetically engineered crops as following.
- Rice does not contain very much vitamin A. In the poorer parts of Asia, where rice is almost the only food of the rural population, a vitamin A shortage is common, leading to early blindness. Therefore, scientists have transferred the genes for vitamin A from other species into rice, creating a category of rice which is rich in vitamin A—the amount of rice in a typical third world is sufficient to prevent blindness.
- Cotton farmers are plagued by various insect pests, such as the boll budworm, the tobacco budworm, and the pink bollworm. In the south of USA, where most of cotton is raised, these insects were controlled using chemical insecticides which contains a bacterium called Bacillus thuringiensis, and this bacterium is harmless to almost everything else in the field except insects.
- A recent innovation is a plant intended not for food but for quality control. It contains a gene derived from a luminescent jellyfish, but in all other ways it is identical to the food crop—it is planted alongside.
- Making paper requires large amounts of natural cellulose. Some can be derived from recycling, but most of our paper is made from freshly cut trees. The best trees for paper-making are fast growing softwoods with low resin content, like aspens. Genetic engineers have transferred genes for pest resistance and herbicide resistance into aspen and have tinkered with the genetic switches that promote growth to create a fast growing aspen that could supply our paper needs using considerably less land.
In general, the benefits for agriculture by using genetic engineering is that biotechnology is needed to feed the growing population of the world, especially the Third World, it could reduce chemical inputs, which will be good for the environment, and it makes higher yields, which is benefiting farmers and consumers. Also genetic engineering have other more uses for agriculture but there are some risks that are brought by it. We can divide these risks into two core parts, one is health risk and another is environmental risk. For health, there is a proof already exists that allergens can be transferred to plants through genetic engineering; some genetically engineered foods have killed some people; we could waste our defence against disease; spread of virulence among pathogens across species by genes transfer and recombination. For environment, planet-wide genetic engineering tests, releases and crop growing could influence the normal environment; new ‘super crops’ with an inbuilt resistance to disease or pests could become ‘super weeds’; there are risks relating to gene transfer from genetically engineered plants to micro-organisms; new plant viruses could develop from genetically engineered crops that are virus resistant; major insect pest could develop bio-pesticide resistance; some smaller genetic companies will inevitably take risks when they are playing catch-up; “genetic pollution” by self-replicating genetically modified organisms is irreversible.
In the aspect of medicine, people can apply genetic engineering into it nowadays. Cell is the basic unit to form body, and in an organism, cells depend on each other to perform various functions and tasks; some cells will produce enzymes, other will store sugars or fat; different cells again will build the skeleton or be in charge of communication like nerve cells; others are there for defence, such as white blood cells or stinging cells in jelly fish and plants. Therefore, what people do is to insert, modify or extract genes of patients’ various cells in order to predict or cure diseases. Genetic prediction of disposition to disease is an important technology that can do the prediction of predisposition to diseases such as diabetes, rheumatism and even to areas such as delinquency which means a tendency to suffer from schizophrenia etc. Gene technology is also used in the manufacture of medicines from microorganisms. There are lots of hormones essential for life in the human body which are not produced in certain kind of illness. Insulin is the best known example. Erythropoetin is another. This is formed in the tubular-epithelial cells of the kidneys. It is essential for the production of red blood corpuscles in the bone marrow and individuals with too little erythropoetin become anaemic through forming too few of these. Genetic engineering is now used in immunological research, for instance in combating cancer. Special cells are involved in immune defence so that there is interest in seeing if it is possible to control these cells in such a way that they attack tumour tissue directly without damaging other living tissues. This application has not yet reached medical practice but it is being researched intensively. Another area, which has a big future, is to modify genes in the cells of the body directly. It is now possible to remove body cells, control them genetically by inserting.
On the other hand, there are some negative effects exist against genetic engineering in medicine. People think heredity is very important for human beings and genetic engineering could affect even change or control it. Children could lose their early childhood which is important for them to imitative adults in order to learn various knowledge by using genetic technology and make their mentality and physicality grow quicker. That is not good for child and not equal for them if people do so. And some charities and some organisations oppose people use gene technology in the field of iatrology such as changing heredity of human beings.
In terms of new technology—cloning, it is the embodiment of genetic technology. What is cloning? Cloning is the creation of an organism or a number of organisms, which is or are genetically identical to another. In the current dispute, we are likely to hear cloning referred to in one of two ways, which are Reproductive cloning and Therapeutic cloning. The former refers to the creation of a new person with the same genetic composing as someone who is alive or has lived. The latter refers to using cloning techniques to develop the growth of embryos in order to create new organs or cells for medical and research purposes. In 1996, the first cloned sheep—Dolly was born and her existence is revealed in 1997. By using older techniques as well as some new tricks, Scottish researcher Ian Wilmut cloned Dolly from an adult cell. He hopes to use this scientific advancement to clone transgenic critters, but there was a debate appeared about cloning human. People think scientists could extend cloning techniques to human beings, which is related to human ethic. If so, cloning human will shuffle the system of human societies such as crimes will be increased caused by cloning people who are the same as another, it is extremely difficult for laws to amerce the real thugs. Besides, cloning could influence the heredity of human, which is the same case as what we mentioned before. People could clone better stuffs such as minds, appearances to their prenatal babies and make them be smarter or more beautiful. But it is incorrect in the ethic of human societies. Therefore, many countries have already established some laws to avoid human cloning. However, there are some benefits from human cloning such as clone organ, tissue for medical care. For example, human cloning technology could be used to cure heart attacks; it could be used in plastic, reconstructive and cosmetic surgery; also it is possible to ensure that we no longer suffer because of our defective genes in the future. Consequently, human cloning is a vexed topic among people all over the world.
In conclusion, all we mentioned above are about the applications of genetic technique in terms of agriculture, medicine and cloning. Although genetic engineering brings some benefits for us, there are still some problems and debates about it. Could new genes destroy us? When is gene technology right or wrong? Should we birth genetically engineered babies to improve our breed? All of these and other more questions are regard by everyone but nobody could answer an exact answer. So what scientists should do is do further research about genetic engineering and solve difficulties which are potential for us now. We hope the success of genetic revolution will be achieved in the future history of human beings.
BIBLIOGRAPHY
·C.J. Clegg, <Genetic & Evolution>, John Murray LTD, 1999
·Craig Donnellan, <Cloning>, Independence, 2000
·Dr Patrick Dixon, <The genetic revolution>, Kingsway Publications LTD, 1993