At some time in our lives, we have all heard of some form of genetic engineering whether it was on the news, at school or in the workplace. Most people do not realise just how much time and money is now going into creating solutions to our everyday problems using genetic engineering, problems such as our food crops being destroyed by viruses. But it doesn't just stop there. Genetic engineering is now going much further than just solving everyday problems.
Scientists are now trying to solve deeper problems. For example, they are trying to create perfect crops and livestock for farmers and even perfect children for parents. Genetic engineering refers to the technologies that are being used to change the genetic make-up of cells and transfer genes from one species to another. Genes are complex chemical units contained within chromosomes.
They determine the characteristics of an organism. Genetic engineering involves either altering these characteristics within an organism or transferring them to another. Through genetic engineering, organisms are given new combinations of genes and therefore new combinations of characteristics that do not occur naturally. Two American scientists, Stanley Cohen and Herbert Boyer, discovered the cloning of genetically engineered molecules. Cohen and Boyer first met at a conference in Hawaii, 1972. At that time, Boyer was a biochemist working at the University of California and Cohen was an associate professor at Stanford University.
Boyer's laboratory had quite recently isolated an enzyme that could be used to cut strands of DNA into precise segments. These strands could be attached to other strands of DNA. Cohen had found a way to cross species boundaries, using cells of DNA called plasmids, and had also came up with a way of isolating and cloning genes. When cloning, scientists take cells from one organism that has particular characteristics that they believe to be useful. Cells are then taken from another organism, usually of the same species. This second set of cells usually contains different characteristics that are also believed to be useful.
The two are combined and a new animal is grown that is an exact copy of the original. This animal has been cloned for beneficial results. Boyer and Cohen decided to combine their discoveries and make better use of them. Boyer's enzyme would allow Cohen to introduce specific DNA segments to plasmids. These plasmids could be used to clone precise, previously targeted strands of DNA. Within four months Boyer and Cohen's joint efforts had resulted in cloning predetermined patterns of DNA.
After further refinements, three patents, and marketing and licensing agreements, Boyer and Cohen had given birth to a huge international industry that is now benefiting people all over the world. There are different forms of genetic engineering including cloning, modified food and vegetative reproduction. Food products can be genetically modified for various advantages over natural foodstuffs. For example, tomatoes have been genetically modified so that they grow square in shape instead of round. This would benefit packaging. Food products can also be genetically modified for reasons of entertainment.
Carrots have been modified to be purple instead of orange for no reasons of advantage whatsoever. Vegetative reproduction is considered by some people to be a natural form of cloning. When a plant has matured, it grows extra leaves usually on long spindly vines. These extra leaves are then sometimes cut off and placed in pots of soil. Given the correct conditions and proper care, these cuttings will grow roots and develop into a new plant that is identical to its parent. There are a number of techniques for moving genes artificially.
The oldest of these techniques is called Recombinant DNA. There are other, more modern methods of moving genes artificially such as electro- and chemical poration, microinjection and biobalistics. Recombinant DNA techniques rely on biological vectors such as plasmids or viruses to carry foreign genes into cells. When using plasmids to move genes artificially, new genetic material is inserted into the cells next to the cells of the bacteria containing the plasmids. Often the bacteria will take up the gene and begin to produce the protein for the new gene codes. Viruses are infectious particles that contain genetic material to which a new gene can be added.
When using viruses to move genes artificially, the virus carries the new gene into a recipient cell in the process of infecting that cell. The virus can also be disabled so that while it can carry a new gene into a cell, it cannot redirect the cells genetic machines to make thousands of copies of itself. Microinjection is a more modern method of artificially transferring genes. Unlike Recombinant DNA, it does not rely on biological vectors like plasmids or viruses.
Microinjection is exactly what you would expect it to be by its name. It involves simply injecting gene material containing the new gene into the recipient cell. Where the cell is large enough, as many animal and plant cells are, a fine tipped glass needle can be used. Scientists are unsure how, but the injected genes find their way to the recipient cell's genes and incorporate themselves among them. This may be a cause for concern because scientists are not aware of exactly what they are doing, they may be doing more harm than good. Other modern ways of transferring genes are Chemical and Electroporation.
These methods involve creating pores in the cell membrane and allowing entry of the new genes. In Chemical Poration, the cells are bathed in solutions of special chemicals. In Electroporation cells are subjected to a weak electric current. Bio ballistics uses projectile methods and small pieces of metal to deliver the genetic material to the interior of the cell. The pieces of metal are smaller than the diameter of the target cell, and are coated with genetic material. A projectile method propels the metal coated with genetic material using a piece of equipment like a shotgun.
A perforated metal plate stops the cell cartridge, but allows the tiny metal pieces to pass through and into the living cells on the other side. Once inside the cell, the genetic material is transported to the nucleus where it is incorporated among the host genes. Genetically engineered organisms have many advantages in agriculture, including novel foods, pesticides and animal drugs. Lists of Agricultural Research Topics suggest a variety of benefits companies have envisioned, including animals engineered for leaner meat, plants engineered for herbicide tolerance or insect resistance, bacteria engineered to produce drugs for livestock and more. The companies that develop and market these products obviously think that they represent benefits to society. The products only seem to have advantages in certain circumstances.
Take tomatoes that have been genetically engineered to have an extra long shelf life, for example. They can be useful if the company's aim is to transport the tomatoes to markets that are far from the fields where the tomatoes were grown. They are of much less of an advantage if they are to be sold locally. It has been said that all genetically engineered foods are toxic and that all genetically engineered organisms proliferate the environment but this is not true. Scientists have not found any harms of genetically engineered organisms or food so far. Scientists believe that genetically engineered organisms could potentially impact both human health and the environment.
Once the harms have been identified, scientists will try to discover how frequently these risks are likely to occur. They will determine this using a method called risk assessment. Most of the potential harmful effects on human health that scientists believe may be caused by genetically engineered organisms are associated with the growth and consumption of genetically engineered crops. There may be different risks associated with genetically engineered animals that would, like genetically engineered plants, depend largely on the new traits introduced into the organism. Genetically engineered crops may introduce new food related allergies to those few sensitive individuals who would not know to avoid some genetically engineered foods. For example, if a gene is transferred from one of the allergenic proteins in milk into a vegetable like sweet corn, mothers who know to avoid giving their sensitive children milk, may not know to avoid giving them genetically engineered sweet corn containing milk proteins.
Virtually all known food allergens are proteins. Genetic engineering routinely moves proteins into the food supply from organisms that have never been consumed as foods. Some of these proteins could be food allergens. Recent research has shown that genetic engineering is causing previously safe foods to be allergenic. Scientists from the University of Nebraska studied this recently. Their results show that soybeans genetically engineered to contain proteins from Brazil nuts caused reactions amongst individuals who were allergic to Brazil nuts.
Scientists are unable to predict if a particular protein will be a food allergen in any other way than simply through 'trial and error' or, as they call it, experience. Therefore, importing proteins is a gamble, especially if they are from non-food sources. Genes are being added to plants to enable them to remove heavy metals like mercury from the soil and concentrate them in plant tissue. This is being done to make it possible to use Sludge as fertiliser. Sludge is a mixture of fertilisers with many useful plant nutrients. These ingredients make it very useful as fertiliser but it is also contaminated with toxic heavy metals.
Scientists have found a method of engineering plants to enable them to remove and make use of these toxic heavy metals. The use of toxic metals in plants could be a risk to human health as the foods may become contaminated. There is also an environmental risk when disposing of the metal compound in the plant after harvesting. Risks do not only occur when adding genes to organisms they can occur when removing genes.
The best example is something we " ve all heard of: decaffeinated coffee. By decaffeinating coffee beans we can simply delete or turn off genes associated with caffeine production. Another way of doing this is to use chemicals to remove the caffeine. This can create a problem as caffeine helps to protect the bean against fungi. Beans that are unable to produce caffeine may be coated in fungi that can produce toxins. Turning off these genes is not commonly used as it is very costly whereas removing the caffeine is much more cost effective and is used as a normal method of producing decaffeinated coffee.
Clearly, scientists are unable to identify the full set of risks that are associated with genetic engineering. The ability to predict what might go wrong with a technology is limited by the currently incomplete understanding of physiology, genetics and nutrition. These are not the only risks posed by genetically engineered plants. Obviously, there are also risks from genetically engineered animals. Genes inserted into crops may not stay in the fields they were placed in. If relatives of the altered crops are growing nearby, the new gene can easily move via pollen to the relative plants.
The new traits might have an effect on other crops making them grow in unwanted places resulting in them being weeds, as scientists define them (all plants in places where humans do not want them are considered weeds). This is also true for genetically engineered animals. They could escape from the fields that they are placed in and could mix with other animals, putting these other animals at risk. Crops that have been genetically engineered to be resistant against chemical herbicides are tightly linked to the use of particular pesticides. Adoption of these crops could lead to changes in the mix of chemical herbicides used throughout the world. Chemical herbicides differ in their environmental toxicity.
The changing patterns may result in greater levels of environmental harm overall. If the use of herbicide tolerant crops is too widespread, it could result in the rapid evolution of resistance to herbicides in weeds. Many insects have genes that make them susceptible to pesticides. These genes are very important as they allow pesticides to remain effective pest controls. The weaker the pesticide, the more important these genes are. Certain genetically engineered crops threaten the continued susceptibility of pests to one of the most valuable pesticides in nature: the Bacillus thuringiensis or Bt toxin.
'Bt crops' are genetically engineered to contain a gene for the Bt toxin. Pests are constantly exposed to the toxin because the crops produce it in most plant tissues. This constant exposure will eventually make the pests immune to the toxin and will eventually make pesticides useless, unless drastic measures are taken to avoid the development of such resistance. Genetically engineered plants can also have an effect on animals. For example, engineering crop plants could endanger animals that consume crop debris left in the fields after harvesting. Fish have been engineered to enable them to eat metals.
These fish could be harmful if eaten by other animals. The application that is one of the most commonly talked about in genetic engineering is the production of virus-tolerant crops. They may seem like a good idea but they may only make things worse. They pose risks of creating new, or worse viruses through a mechanism called recombination. Recombination can occur naturally or artificially between the plant-produced viral genes and closely related genes of incoming viruses. Recombination may produce viruses that can infect a wider range of hosts or that may be worse than the parent viruses.
Like human health risks, scientists think it is unlikely that they have uncovered all the potential harms that genetic engineering may have on the environment. The ability to predict what might go wrong with a technology is limited by the currently incomplete understanding of biology and ecology. The most famous of all genetically engineered animals has to be Dolly the Sheep. Dolly, who was engineered in Scotland, has been said to be a clone but in actual fact "she is less of a 'clone' than are identical twins." Identical twins have identical DNA from the nucleus and egg substance but they are both different people. The nucleus of an adult sheep cell - in this case from the cell of the udder - was inserted into another sheep's egg, which had been previously prepared by having its own nucleus removed.
The embryo was then placed in the womb where it developed into a lamb. Dolly grew with most of her characteristics originating from the single nucleus of the adult cell. The University of Massachusetts combined cloning with genetic engineering (also called transgenic's) and produced two healthy calves named Charlie and George. They are the first calves to be engineered from genetically altered somatic (body) cells. The animals are genetically identical to each other. The scientist who engineered the calves have developed a reliable way to introduce new characteristics into livestock cells and produce an unlimited number of clones.
The calves have a 'marker' gene to show that they are products of genetic engineering. It may also be a good idea for them to have a special barcode or serial number as they are genetically identical to each other. They are very important as they lead the way to the production of similar animals that produce large quantities of therapeutic human proteins in their milk, which could essentially become medicines. These proteins may be extracted and purified and made into pills or injections, or drunk like an ordinary glass of milk. This new field, a combination of pharmaceuticals and farming is called 'pharming'. According to news reports, the US Food and Drug Administration is reviewing an application to market salmon that have been genetically altered to make them grow faster.
If the FDA approves the salmon, they could be from the water to your plate faster than ever before. The company seeking approval, A/F Protein Inc. , claims to have orders for more than 15 million engineered salmon eggs. The FDA are reviewing engineered Atlantic salmon containing foreign genes that stimulate the salmon to grow to market size twice as fast as it takes normal salmon. Researchers have inserted two new genes into the fertiliser salmon eggs.
The first gene is taken from the Chinook salmon. It produces growth hormones. The second gene is a 'promoter', which comes from the ocean pout. The promoter disrupts the salmon's growth cycle. Ecologists are very concerned about the hazards these salmon may cause if released, or escape, into the wild. They may wreak havoc on native salmon populations.
The farmed salmon live in far from escape-proof cages. Their cages can be easily damaged by predators or storms, releasing large numbers of salmon. Once the salmon escape, they are virtually impossible to recapture. There are alternatives to most things in life and genetic engineering is no exception. Many of the alternatives are not other products but instead the systems and methods of sustainable agriculture. One of the best examples of this is crop rotation.
This keeps pests under control by depriving them of the continuous food supply that they need to populate. Crop rotation has many advantages: it controls lots of species of pests rather than just a couple; it does not select for resistance genes, as do genetically engineered crops; it does not result in ongoing pollution of air or water. Crop rotation is far preferable to genetically engineered crops. Before I began my research, I thought that genetic engineering was a great advance in human knowledge and there were not many disadvantages of it. I still think that it is a good thing but there are a lot of risks.
I think that genetic engineering should still be deeply researched to try and fully understand factors such as biology, ecology, physiology, genetics and nutrition to help us overcome some of these risks. Can genetic engineering really create the perfect race? My answer is: not yet. If the risks are overcome and scientists understand what they are doing, we could have perfect crops, perfect pets and, most frightening of all, perfect children. Bibliography The beginning of genetic engineering: web > Stanley Cohen and Herbert Boyer: web > Risks of genetic engineering: web > Advantages and disadvantages of genetic engineering: web > Genetically modified food: web > Techniques of genetic engineering: web > Genetically engineered calves, Dolly the sheep: web > Dolly the sheep: web > Dolly the sheep: web.