Genetic engineering today is no longer a new term to the world. Every day in the newspapers, televisions, magazines the new inventions of genetic engineering are noted. Genetic engineering can be described as the practice that manipulates an organism’s genes to produce a desired result. Other techniques that fall into this category are: recombinant DNA technology, genetic modification (GM), and gene splicing.
HISTORY
The roots of genetic engineering are connected to antiquity. The Bible also sheds some light on genetic engineering where selective breeding has been mentioned. Modern genetic engineering began in 1973 when Herbert Boyer and Stanley Cohen used enzymes to cut a bacterial plasmid and inserted another strand of DNA into the gap created. Both DNA fragments were taken from the same type of bacteria. This step became a milestone in the history of genetic engineering. As recently as 1990, a young girl with a severely compromised immune system received gene therapy in which some of her white blood cells were genetically engineered and reintroduced into her bloodstream so that her immune system could function properly.
PROMISE
Genetic engineers hope that, with enough knowledge and experimentation, it will be possible in the future to create “custom” organisms. This will lead to new innovations, possibly including customized bacteria to clean up chemical spills or fruit trees that produce different types of fruit in different seasons. In this way, new types of organisms and plants can be developed.
PROCESS
Genetic engineering requires three elements: the gene to be transferred, a host cell into which the gene is inserted, and a vector to carry out the transfer. First, the genes needed to be manipulated must be ‘isolated’ from the main strand of DNA. The genes are then ‘inserted’ into a transfer medium such as the plasmid. Third, the transfer medium (ie, the plasmid) is inserted into the organism to be modified. The next step is element transformation whereby a number of different methods including DNA guns, bacterial transformation and viral insertion can be used to apply the transfer medium to the new organism. Finally, a separation stage occurs, where the genetically modified organism (GMO) is isolated from other organisms that have not been successfully modified.
APPLICATIONS
Genetic engineering has affected all fields of life, be it agriculture, food and processing industry, other commercial industries, etc. we will discuss them one by one.
1. Agricultural applications
With the help of genetic engineering it would be possible to prepare clones of genetically engineered plants and animals of agricultural importance that have desirable characteristics. This would increase the nutritional value of plant and animal foods. Genetic engineering could lead to the development of plants that would fix nitrogen directly from the atmosphere, instead of expensive fertilizers. The creation of nitrogen-fixing bacteria that can live on the roots of crop plants would make fertilizing fields unnecessary. The production of such self-fertilizing food crops could spark a new green revolution. Genetic engineering could create microorganisms that could be used for biological control of harmful pathogens, insect pests, etc.
2.Environmental applications
Genetically modified microorganisms could be used for waste degradation, in sewage, oil spills, etc. Scientists at the General Electric Laboratories in New York added plasmids to create strains of Pseudomonas that can break down a variety of hydrocarbons and are now used to clean up oil spills. It can degrade 60% of crude oil, while the four parents from which it is derived break down only a few compounds.
3. Industrial applications
Industrial applications of recombinant DNA technology include the synthesis of substances of commercial importance in industry and pharmacy, the improvement of existing fermentation processes, and the production of proteins from waste.
4. Medicinal Applications
Among the medical applications of genetic engineering are the production of hormones, vaccines, interferon; enzymes, antibodies, antibiotics and vitamins, and in gene therapy for some hereditary diseases.
hormones
The hormone insulin is currently produced commercially by extraction from the pancreas of cows and pigs. However, about 5% of patients suffer allergic reactions to animal-produced insulin due to its slight difference in structure from human insulin. Human insulin genes have been implanted into bacteria which therefore become capable of synthesizing insulin. Bacterial insulin is identical to human insulin in that it is encoded by human genes.
Vaccines
Injecting an animal with an inactivated virus stimulates it to produce antibodies against the viral proteins. These antibodies protect the animal against infection by the same virus by binding to the virus. Phagocytic cells then clear the virus. Vaccines are made by growing the disease-causing organism in large numbers. This process is often dangerous or impossible. In addition, there are difficulties in making the vaccine harmless.
interferon
Interferons are virus-induced proteins produced by virus-infected cells. They seem to be the body’s first line of defense against viruses. The interferon response is much faster than the antibody response. Interferons are antivirals in action. A type of interferon can work. Against many different viruses, i.e. it is not virus specific. However, it is species specific. Interferon from one organism does not protect cells from another organism against viruses. Interferon provides a natural defense against viral diseases such as hepatitis and influenza. It also appears to be effective against certain types of cancer, especially breast and lymph node cancer. Natural interferon is obtained from human blood cells and other tissues. It is produced in very small quantities.
enzymes
The enzyme urokinase, which is used to dissolve blood clots, has been produced by genetically modified microorganisms.
antibodies
One of the goals of genetic engineering is the production of hybridomas. These are long-lived cells that can produce antibodies to use against disease.
5. Gene therapy for the treatment of hereditary diseases
The first gene transplant experiments involved in vitro gene transplantation into single cells or bacteria. Gene transplant experiments have now been extended to live animals.
6. In understanding biological processes
Genetic engineering techniques have been used to gain basic knowledge about biological processes such as gene structure and expression, chromosome mapping, cell differentiation, and integration of viral genomes. This could lead to a better understanding of the genetics of plants and animals, and ultimately of humans.
7. Human applications
One of the most exciting potential applications of genetic engineering involves the treatment of genetic disorders. Medical scientists now know of about 3,000 disorders that arise due to errors in an individual’s DNA. Conditions such as sickle cell disease, Tay-Sachs disease, Duchenne muscular dystrophy, Huntington’s chorea, cystic fibrosis, and Lesch-Nyhan syndrome result from the loss, misinsertion, or change of a single nitrogenous base in a DNA molecule. Genetic engineering makes it possible for scientists to provide people who lack a certain gene with correct copies of that gene. The human cloning proposal is yet to come to the fore. Genetic engineering has benefited infertile couples.
Genetic engineering safeguards
General safeguards for recombinant DNA research are outlined below:
1. Genes coding for the synthesis of toxins or antibiotics should not be introduced into bacteria without proper precautions
2. Neither should animal genes, animal viruses or tumor viruses be introduced into bacteria without due precautions.
3. Laboratory facilities should be equipped to reduce the ‘chance’ of escape of pathogenic microorganisms through the use of microbial safety cabinets, hoods, negative pressure laboratories, special traps in drain lines, and vacuum lines.
4. The use of microorganisms that occupy special ecological niches, such as hot springs and salt water, should be encouraged. If such organisms escape, they will not be able to survive.
5. The use of non-conjugative plasmids is recommended as plasmid cloning vectors, since such plasmids cannot promote their own transfer by conjugation.
Dangers of genetic engineering
Recombinant DNA research involves potential dangers. Genetic engineering could create dangerous new life forms, either accidentally or deliberately. A host microorganism can acquire harmful characteristics as a result of the insertion of foreign genes. If disease-carrying microorganisms formed as a result of genetic manipulation were to escape laboratories, they could cause a variety of diseases. For example, Streptococcus, a bacterium that causes rheumatic fever, scarlet fever, strep throat, and kidney disease, never acquired resistance to penicillin in nature. If a plasmid carrying a penicillin resistance gene is introduced into Streptococcus, it would confer penicillin resistance on the bacterium. The penicillin would now become ineffective against the resistant organism.