Benefits of Genetic Engineering in Agriculture
The production of technologies based on genetic engineering is often referred as modern biotechnology. With the improvement of genetic engineering techniques, the time for generating and evaluating new germplasm (a collection of genetic resources for an organism) can be drastically reduced. Genetic engineering may ultimately have their most significant effect on agriculture. Recent advances have raised possibility of development of new plant germplasm through introduction of any gene from any organism into plant.
With respect to agriculture, modern biotechnology has been considered as the second phase of green revolution. Organisms whose genes have been altered by manipulation are called genetically modified organism (GMO). The working of GMO is due to nature of transferred genes, nature of host organism and food web formed. Some useful benefits of genetically modified plants in agricultural biotechnology are: 1. Improved nutritional quality 2. Better Nitrogen Fixation 3. Disease resistant Plant 4. Enhanced efficiency of minerals used by plants to prevent early exhaustion of fertility of soil. 5. Reduced post harvest losses
The first genetically modified food was Flavr Savr Tomato which was resistant to rotting.
Another genetically modified food is golden rice (Pro Vitamin A enriched). Several other genetically modified foods include, soybeans, corn, cotton, seed oil etc have been formed. But many controversies are associated with genetically modified food including environment and human safety, ethics, food security, poverty reduction etc.
Some success has been achieved in developing varieties resistant to herbicides, viral diseases and insect pest. Genetic engineering promises rapid acceleration of plant breeding efforts for crop improvement.
Benefits of genetic engineering: Production of valuable Proteins
Another benefit of genetic engineering is realized in production of valuable proteins. Recombinant DNA made possible the use of bacteria to produce proteins of medical importance. One such example is that of genetically engineered human insulin which is of great importance and now marketed throughout the world.
Some important genetically engineered proteins include:
Human Insulin
Human insulin or Humulin has great importance. Earlier, patients could not tolerate pig insulin, as it has slightly different amino acid sequence as compared to human. Humulin eventually became cheaper than that extracted from animal pancreas and is now available.
Interferon
Interferon is an antiviral agent which is secreted by cells which are attacked by virus. Several types of genetically engineered interferon are available in market and gives rise to antitumoral effect (thwarting formation of cancerous tumors).
Growth hormone
In humans, growth hormone helps in treatment of hypopituitary dwarfs. Genetically engineered growth hormones may prove useful in the treatment of bone fractures, skin burns and bleeding ulcers of digestive tract. The human hormone is marketed in United States and bovine hormone is expected to yield bigger cattle and thus more beef. Hence growth hormones are commercially very demanding.
Benefits of genetic engineering: Vaccine production
Vaccines produced by genetic engineering offer an advantage that the microbial strains from which the proteins are extracted do not contain complete viruses. And thus, there are no risks of accidental inoculation with live virus.
Cloning directly into vaccinia virus DNA holds great promise, although vaccines so produced are not yet in the market. Recombinant vaccinia viruses for example, a gene from genital herpes virus within its DNA, can multiply and can subsequently be inoculated into humans. The vaccinia virus produces mild infection, and expresses some of herpes virus protein and produces immunity. This is very similar in a way to what Edward Jenner did over 100 years ago when he introduced the first vaccination scheme, which eventually led to the extinction of smallpox.
Vaccines can be produced using recombinant DNA technology or using cell culture. Vaccines of common use are usually produced by cell cultures or animals. Such vaccines contain weakened or inactivated pathogens. Crop plants can bear cheaper bioreactors to produce antigens to be utilized as Edible vaccines. These edible vaccines are said to be a cheap alternative as compared to recombinant vaccines.
The transgenic plants are treated as edible vaccines and consumption of these transgenic plants viz. transgenic banana and tomato cure diseases like Cholera and Hepatitis-B. Foot and mouth diseases can be cured by feeding them transgenic sugar beet. In the near future, these vaccines can be used as conventional vaccines.
Humulin was the first therapeutic product to be made commercially by genetically engineered bacterium. Recently a genetically engineered malarial vaccine SPF – 66 has been produced.
Benefits of Genetic Engineering: Production of Disease Resistant Plants
Genetic engineering, promises to have an enormous impact on the improvement of crop species. Genetic transformation can boost plant breeding efforts for developing disease resistant varieties. Now the disease resistant genes can be isolated and transferred to high yielding susceptible plants to produce pathogen free plants. Through gene sequencing, it is possible to locate gene and after identification, gene is isolated and transferred to the host. Several disease resistant somaclones have been identified for resistance to severe potato disease, early blight of potato, caused by Alternaria Solani. Scientists are using Agrobacterium gene transfer system to produce tobacco plants with increased resistance to Tobacco Mosaic Virus (TMV).
Medicine
Genetic engineering has resulted in a series of medical products. The first two commercially prepared products from recombinant DNA technology were insulin and human growth hormone, both of which were cultured in the E. coli bacteria. Since then a plethora of products have appeared on the market, including the following abbreviated list, all made in E. coli:
Bionote
A vaccine is usually a harmless version of a bacterium or virus that is injected into an organism to activate the immune system to attack and destroy similar substances in the future. * Tumor necrosis factor. Treatment for certain tumor cells * Interleukin-2 (IL-2). Cancer treatment, immune deficiency, and HIV infection treatment * Prourokinase. Treatment for heart attacks * Taxol. Treatment for ovarian cancer * Interferon. Treatment for cancer and viral infections
In addition, a number of vaccines are now commercially prepared from recombinant hosts. At one time vaccines were made by denaturing the disease and then injecting it into humans with the hope that it would activate their immune system to fight future intrusions by that invader. Unfortunately, the patient sometimes still ended up with the disease.
With DNA technology, only the identifiable outside shell of the microorganism is needed, copied, and injected into a harmless host to create the vaccine. This method is likely to be much safer because the actual disease-causing microbe is not transferred to the host. The immune system is activated by specific proteins on the surface of the microorganism -e. DNA technology takes that into account and only utilizes identifying surface features for the vaccine. Currently vaccines for the hepatitis B virus, herpes type 2 viruses, and malaria are in development for trial use in the near future.
Agriculture
Crop plants have been and continue to be the focus of biotechnology as efforts are made to improve yield and profitability by improving crop resistance to insects and certain herbicides and delaying ripening (for better transport and spoilage resistance). The creation of a transgenic plant, one that has received genes from another organism, proved more difficult than animals. Unlike animals, finding a vector for plants proved to be difficult until the isolation of the Ti plasmid, harvested from a tumor-inducing (Ti) bacteria found in the soil. The plasmid is “shot” into a cell, where the plasmid readily attaches to the plant's DNA. Although successful in fruits and vegetables, the Ti plasmid has generated limited success in grain crops.
Creating a crop that is resistant to a specific herbicide proved to be a success because the herbicide eliminated weed competition from the crop plant. Researchers discovered herbicide-resistant bacteria, isolated the genes responsible for the condition, and “shot” them into a crop plant, which then proved to be resistant to that herbicide. Similarly, insect-resistant plants are becoming available as researchers discover bacterial enzymes that destroy or immobilize unwanted herbivores, and others that increase nitrogen fixation in the soil for use by plants.
Geneticists are on the threshold of a major agricultural breakthrough. All plants need nitrogen to grow. In fact, nitrogen is one of the three most important nutrients a plant requires. Although the atmosphere is approximately 78 percent nitrogen, it is in a form that is unusable to plants. However, a naturally occurring rhizobium bacterium is found in the soil and converts atmospheric nitrogen into a form usable by plants. These nitrogen-fixing bacteria are also found naturally occurring in the legumes of certain plants such as soybeans and peanuts. Because they contain these unusual bacteria, they can grow in nitrogen-deficient soil that prohibits the growth of other crop plants. Researchers hope that by isolating these bacteria, they can identify the DNA segment that codes for nitrogen fixation, remove the segment, and insert it into the DNA of a profitable cash crop! In so doing, the new transgenic crop plants could live in new fringe territories, which are areas normally not suitable for their growth, and grow in current locations without the addition of costly fertilizers!
Animal Husbandry
Neither the use of animal vaccines nor adding bovine growth hormones to cows to dramatically increase milk production can match the real excitement in animal husbandry: transgenic animals and clones.
Transgenic animals model advancements in DNA technology in their development. The mechanism for creating one can be described in three steps: 1. Healthy egg cells are removed from a female of the host animal and fertilized in the laboratory. 2. The desired gene from another species is identified, isolated, and cloned. 3. The cloned genes are injected directly into the eggs, which are then surgically implanted in the host female, where the embryo undergoes a normal development process.
It is hoped that this process will provide a cheap and rapid means of generating desired enzymes, other proteins, and increased production of meat, wool, and other animal products through common, natural functions.
Ever since 1997 when Dolly was cloned, research and experimentation to clone useful livestock has continued unceasingly. The attractiveness of cloning is the knowledge that the offspring will be genetically identical to the parent as in asexual reproduction. Four steps describe the general process: 1. A differentiated cell, one that has become specialized during development, with its diploid nucleus is removed from an animal to provide the DNA source for the clone. 2. An egg cell from a similar animal is recovered and the nucleus is removed, leaving only the cytoplasm and cytoplasm organelles. 3. The two egg cells are fused with an electric current to form a single diploid cell, which then begins normal cell division. 4. The developing embryo is placed in a surrogate mother, who then undergoes a normal pregnancy.
The basic principle of genetic engineering is gene transfer, achieved by various methods to produce recombinant proteins, genetically modified microorganisms, transgenic plants and transgenic animals for commercial application. Genetic engineering, thus ultimately influences the growth of biotech industry. The two significant feature of genetic engineering is production of beneficial proteins and enzymes in surplus quantities and creation of transgenic plants, transgenic animals and genetically modified microorganisms with new characters beneficial for themselves using recombinant DNA technology. The discovery of a new protein either with a therapeutic property or application in food industry by a researcher or scientist would not have reached humans, for the use by humans without the application of genetic engineering in mass producing such proteins.

Recombinant proteins production and uses: The industrial production of proteins is done by transferring the desired gene responsible for the particular protein to be manufactured from the source organism to the preferred host organism through recombinant DNA technology. The host organism can be a bacteria or a eukaryote. The most preferred bacterial host is Escherichia coli for industrial production of proteins. The well established gene structure, faster growth rate, easy to cultivate and handle are the salient features of the E. coli bacterium fascinated the bio technologists to use this in recombinant protein production. Besides all these commendable characters of E. coli, the final output product is found to be unstable and difficult to purify. As a result research encouraged the use of eukaryotic host like yeast, cells of insects and cells of mammals in protein production. The proteins produced in this way find its way into pharmaceutical industry and food industry.

The recombinant proteins produced in the industry using the techniques of genetic engineering acts as drugs for various human diseases. To name a few, insulin produced for diabetes, alpha 1- antitrypsin in treating emphysema, calcitonin to treat rickets, interferon to treat viral infections and cancer, Factor VIII for hemophilia, production of growth hormone to act against growth retardation and chorionic gonadotrophin in the treatment of infertility. Some of the industrial manufactured enzymes occupy a vital position in the food industry. For example, the recombinant enzymes like rennin and lipase are used in cheese making, the role of alpha- amylase in beer industry, the antioxidant property of the industrially produced enzyme catalase and the use of protease in detergents.

Uses of Transgenic plants: In order to improve the quality and quantity of plants, traditional method of plant breeding is replaced by the creation of transgenic plants. The transgenic plants are plants carrying foreign genes introduced deliberately into them to develop a new character useful for the plant. The infection of plants by microorganism mostly viruses, poor production and decline in quality of plants due to attack by insects and the plants inability to withstand the pesticide or the weedicide used in the agriculture process welcomed the genetic engineering technology to develop transgenic plants with new characters like resistance to infections, defensive against the attacking insects and resistance to pesticides or weedicide.

The transfer of gene responsible for the protein protoxin from Bacillus thuringiensis to plants to develop resistance against the attacking insects is a remarkable example. Also the digestive action of the insects on the plants is restricted or inhibited by transfer of gene responsible for a particular protein with the property to arrest protease activity. The pesticides and weedicides used to destroy the pests and weeds is also a threat to the cultivated plants. The effects of such chemicals are alleviated by developing a new character called resistance to chemicals in plants. Development of resistance in plants against the weedicide glyphosate states the role of genetic engineering in plant breeding.

Uses Transgenic animals: Transgenic animals are animals carrying foreign genes deliberately introduced into them and exhibiting the characteristics of the introduced gene. Animals are suitable for various research activities trying to help mankind. In that way transgenic animals are created to study human diseases to derive appropriate treatment methods and to develop and identify the drug useful to treat the disease. The presence of human proteins in milk of animals is made possible by genetic engineering. Gene transfer is done in animals to increase the milk production and to increase the growth.