Genetic engineering is the alteration or deliberate modification of genetic code by artificial means.It involves modification of the characteristics of an organism by manipulating its genetic material. Further,genetic engineering refers to a set of technologies that are being used to change the genetic makeup of cells and move genes across species boundaries to produce novel organisms. The techniques involve highly sophisticated manipulations of genetic material and other biologically important chemicals.
Genes are the chemical blueprints that determine an organism's traits. Moving genes from one organism to another transfers those traits. Through genetic engineering, organisms are given new combinations of genes—and therefore new combinations of traits—that do not occur in nature and, indeed, cannot be developed by natural means. Such an artificial technology is radically different from traditional plant and animal breeding.
Nature can produce organisms with new gene combinations through sexual reproduction. A brown cow bred to a yellow cow may produce a calf of a completely new color. But reproductive mechanisms limit the number of new combinations. Cows must breed with other cows (or very near relatives). A breeder who wants a purple cow would be able to breed toward one only if the necessary purple genes were available somewhere in a cow or a near relative to cows. A genetic engineer has no such restriction. If purple genes are available anywhere in nature—in a sea urchin or an iris—those genes could be used in attempts to produce purple cows. This unprecedented ability to shuffle genes means that genetic engineers can concoct gene combinations that would never be found in nature.
Where are Genes located ?
Genes are segments of DNA located on chromosomes.DNA is the recipe for life. DNA is a molecule found in the nucleus of every cell and is made up of 4 subunits represented by the letters A, T, G, and C. The order of these subunits in the DNA strand holds a code of information for the cell. Just like the English alphabet makes up words using 26 letters, the genetic language uses 4 letters to spell out the instructions for how to make the proteins an organism will need to grow and live. Small segments of DNA are called genes. Each gene holds the instructions for how to produce a single
protein. This can be compared to a recipe for making a food dish. A recipe is a set of instructions for making a single dish.An organism may have thousands of genes. The set of all genes in an organism is called a genome.
Why are proteins important?
Proteins do the work in cells. They can be part of structures (such as cell walls, organelles, etc). They can regulate reactions that take place in the cell. Or they can serve as enzymes, which speed-up reactions. Everything you see in an organism is either made of proteins or the result of a protein action.
How is genetic engineering done?
Genetic engineering, also called transformation, works by physically removing a gene from one organism and inserting it into another, giving it the ability to express the trait encoded by that gene.It is the process of transferring specific genes from the chromosome of one organism and transplanting them into the chromosome of another organism in such a way that they become a reproductive part of the new organism.
The process that produces the resulting recombinant DNA involves four steps:
- The desired DNA is cleaved from the donating chromosome by the action of restriction enzymes, which recognize and cut specific nucleotide segments, leaving a “sticky end” on both ends. The restriction enzymes also splice the receiving chromosome in a complementary location, again leaving “sticky ends” to receive the desired DNA.
- The desired DNA fragment is inserted into a vector, usually a plasmid, for transfer to the receiving chromosome. Plasmids are an ideal vector because they replicate easily inside host bacteria and readily accept and transfer new genes. Plasmids are circular DNA molecules found in the cytoplasm of bacteria that bond with the desired DNA fragment with the help of the joining enzyme, DNA ligase, to create the resulting recombinant DNA.
- When the host cell reproduces, the plasmids inside also reproduce, making multiple clones of their DNA. Because the plasmid DNA contains the desired as well as unwanted DNA clones, the entire product is referred to as a gene library. The desired gene is similar to one book in that library.
- To recover the desired DNA, the current technology is to screen unwanted cells from the mixture and then use gel electrophoresis to separate the remaining genes by movement on an electric grid. Gel electrophoresis uses a positively charged grid to attract the negatively charged DNA fragments, thereby separating them by size, because the smaller ones will migrate the most. Radioactive or fluorescent probes are added, which attract and bind with the desired DNA to produce visible bands. Once isolated, the DNA is available for commercial use.
How does genetic engineering differ from traditional breeding?
Although the goal of both genetic engineering and traditional plant breeding is to improve an organism’s traits, there are some key differences between them. While genetic engineering manually moves genes from one organism to another, traditional breeding moves genes through mating, or crossing, the organisms in hopes of obtaining offspring with the desired combination of traits.Therefore, half of the genes in the offspring of a cross come from each parent.
Traditional breeding is effective in improving traits, however, when compared with genetic engineering, it does have disadvantages. Since breeding relies on the ability to mate two organisms to move genes, trait improvement is basically limited to those traits that already exist within that species. Genetic engineering, on the other hand, physically removes the genes from one organism and places them into the other. This eliminates the need for mating and allows the movement of genes between organisms of any species. Therefore, the potential traits that can be used are virtually unlimited.Breeding is also less precise than genetic engineering. In breeding, half of the genes from each parent are passed on to the offspring. This may include many undesirable genes for traits that are not wanted in the new organism. Genetic engineering, however, allows for the movement of a single, or a few, genes.
Is there a difference between genetically engineered, genetically modified, and transgenic animals?
The terms genetically engineered, genetically modified, and transgenic are used synonymously. The term transgenic arises from the procedure of transgenesis, one method in which scientists have successfully inserted genes from one species to another. Throughout this package, the terms are used interchangeably to describe the same type of altered species.
What are the benefits of Genetic Engineering ?
Examples of genetically engineered (transgenic) organisms currently on the market include plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content.
Genetic engineering in its present form has been around for approximately 25 years. It has also been a very widely debated topic from its beginning in 1970s. There are many social consequences that are associated with genetic engineering, that makes the overall risk or benefit assessment very complicated. The benefits of genetic engineering in each field is mentioned below.
Medical Treatment: In humans, the most promising benefit of genetic engineering is gene therapy which is the medical treatment of a disease wherein the defective genes are repaired and replaced or therapeutic genes are introduced to fight the disease. Over the past decade, many autoimmune and heart diseases have been treated using gene therapy. Certain diseases like the Huntington's disease, ALS and cystic fibrosis is caused by defective genes. There is hope that a cure for such diseases can be found by either inserting the corrected gene or modifying the defective gene. Eventually, the hope is to completely eliminate genetic diseases and also treat non-genetic diseases with appropriate gene therapy. The latest research in the field makes it possible to repair or grow new muscle cells when they are not working or are damaged.
Pharmacology: Thanks to genetic engineering, the pharmaceutical products available today are far superior to their predecessors. These new products are created by cloning certain genes. Some of the prominent examples are the bio-engineered insulin which was earlier obtained from sheep or cows and the human growth hormone which was earlier obtained from cadavers. New medicines are being made by changing the genetic structure of the plant cell.
Pregnancy Cases: Genetic engineering is also a boon for pregnant women who can choose to have their fetuses screened for genetic defects. These screenings can help the parents and doctors prepare for the arrival of the child who may have special needs during or after the delivery. A possible future benefit of genetic engineering which is very eagerly awaited is that a fetus with a genetic defect could be treated with genetic therapy even before it is born. Research is going on for gene therapy for embryos before it is implanted into the mother via in-vitro fertilization. The latest term coined is 'Designer Babies' wherein the couple can actually choose the features of the baby to be born!
Agriculture: The field of agriculture too greatly benefits from genetic engineering which has improved the genetic fitness of various plant species. The common benefits are increase in the efficiency of photosynthesis, increasing the resistance of the plant to salinity, drought and viruses and also reducing the plant's need for a nitrogen fertilizer.
List of some of the most upfront benefits of genetic engineering :
- Genetic engineering when used on microorganisms help in the creation of new pharmaceuticals which cannot be made in any other way.
- Genetic engineering helps in the process of bio remediation which is the process of cleaning up waste and pollution with the help of living organisms.
- Genetic engineering has helped lower the overall usage of herbicide and pesticide.
- Genetic engineering has helped with the production of vaccines and other drugs in plants.
- Genetic engineering has helped produce quicker and more predictable way of generating new cultivars. Further, the cultivar properties are better known today than it was ever known before.
- Today, genetic engineering can produce sustainable agriculture.Genetic engineering has produced very useful genetically modified breeds which can tolerate factory farming without any suffering.
- In humans, genetic engineering is used to treat genetic disorders and cancer. It also helps in supplying new body parts.
- Although, this has not been done today, genetic engineering has the potential of creating new types of human beings with many advantageous traits.
- Certain bacterial sequences are manipulated to transform waste into ethanol, so that it can be used as a fuel.
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Disadvantages Of Genetic Engineering
1) Genetic engineering is meant to make food crops more resistant to disease, but the mere act of modification of the naturally selected food crops may actually disturb the delicate balance of biodiversity which exists in nature
2) The production of GMOs has negative impacts on the natural ecosystem which are not apparent now but will be apparent in the future. For example, genetic changes in a particular plant or animal might render it harmful to another organism higher up in the food chain and ultimately this effect may build up to destroy the entire food chain in which that plant plays a role.
3) GMOs have been known to retain some of the genetically modified DNA in the final product made for human consumption. Such remnants of genetic material are harful to human health and can cause production of previously unknown allergens.
4) Genetically modified plants and animals have the potential to replace traditional farming or say poultry and meat-producing practices. This will result in destruction of economies based on these products.
5) In the context of applications of genetic engineering in human life, misuse of this technology in the production of biological warfare or weapons is a very major disadvantage.
6) Genetic engineering is being used to create human organs but in the long run if it can create genetically modified, perfect human specimens who are better than the creators than this may be disastrous.
7) Nature selection in man and the resulting diversity of the human genetic pool is essential for the survival of the species. Genetic engineering will interfere with this process too causing unknown complications.
8) Last but not the least in this long list of disadvantages of genetic engineering are the ethical and moral objections which religion has to these techniques. For example, the use of stem cells obtained from unborn human fetuses created and destroyed for this very purpose is unethical for religious people.
It is obvious from the given list of disadvantages of genetic engineering above that there is need to proceed with caution in use and the absolute necessity of creating as well as enforcing ethical legislation to prevent misuse also.Novel organisms bring novel risks, however, as well as the desired benefits. These risks must be carefully assessed to make sure that all effects—both desired and unintended—are benign. Examination of alternatives, and careful case-by-case evaluation of genetic engineering applications is required to move toward sustainability.
Regulation in India
In India, the Genetically Modified Organisms are regulated under the Environment Protection Act 1986 (EPA). In addition the Indian biosafety regulatory framework comprises, 1989 "Rules for the Manufacture, Use, Import, Export and Storage of Hazardous Microorganisms, genetically Modified Organisms and Cells" (1989 Rules), and Department of Biotechnology guidelines, the 1990 "Recombinant DNA Safety Guidelines" (1990 DBT Guidelines) and 1994 "Revised Guidelines for Safety in Biotechnology" (1994 DBT Guidelines) and 1998 "Revised Guidelines for Research in Transgenic Plants and Guidelines for Toxicity and Allergenicity Evaluation of Transgenic Seeds, Plants and Plant Parts" (1998 DBT Guidelines).
The regulations classify activities involving GMOs into four risk categories, provide lists of bacterial, fungal, parasitic and viral agents that fall into each category, and specify the roles of the institution and the company, the IBSC and the RCGM vis à vis the risk categories:Category I comprises routine recombinant DNA experiments conducted inside a laboratory.Category II consists of both laboratory and greenhouse experiments involving transgenes that combat biotic stresses through resistance to herbicides and pesticides.Categories III and IV comprise experiments and field trials where the escape of transgenic traits into the open environment could cause significant alterations in the ecosystem.
Through the biosafety regulations, Government of India established a three-tier regulatory structure at the central level in New Delhi comprising three committees:
The Review Committee on Genetic Manipulation (RCGM) under the Ministry of Science and Technology (MoST).
The Genetic Engineering Approval Committee (GEAC) under the Ministry of Environment and Forestry (MoEF).
The Monitoring and Evaluation Committee (MEC) under DBT/MoST.
DBT provides the secretariat for RCGM and MEC, and the MoEF for GEAC. The GoI also issued directives on the setting up a de-centralised structure consisting of Institutional Biosafety Committees (IBSCs) and State and District Level Committees (SBCCs and DLCs). The biosafety regulations indicate in broad terms the composition and responsibilities of all these six bodies. DBT is represented on all of them except the SBCCs and DLCs. IBSCs have been established in all institutions (public and private) that deal with GMOs. But, even as late as of 2004, only three states (out of a total of twenty-five states and several ‘union territories’ that make up the Indian Union) had created SBCCs, while DLCs have not been set up anywhere. RCGM’s mandate is to assess and decide on the applications submitted by institutions and companies for conducting R&D work, greenhouse tests and contained field tests on plots of less than one acre in size (0.4 hectare).
Approval process for commercial release of GM crops :
- Initially, the company developing the GM crop undertakes several biosafety assessments including, environmental, food, and feed safety assessments in containment.
- This is followed by Bio-safety Research Trials which require prior approval of the regulators, the GEAC and the RCGM.
- Approval for environmental release is accorded by the GEAC after considering the findings of bio-safety studies.
- Finally, commercial release is permitted only for those GM crops found to be safe for humans and the environment.
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