Genetic Engineering technology at a Glance:

In our day to day life we see lot of inventions & discovers. To add to this we list the facts and details about Genetic Engineering (GE).

What is GE?

Genetic Engineering (GE) is a laboratory technique used by scientists to change the DNA of living organisms.

Figure shows how genetic engineering works

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.

Molecular biologists have discovered many enzymes which change the structure of DNA in living organisms. Some of these enzymes can cut and join strands of DNA. Using such enzymes, scientists learned to cut specific genes from DNA and to build customized DNA using these genes. They also learned about vectors, strands of DNA such as viruses, which can infect a cell and insert themselves into its DNA.

With this knowledge, scientists started to build vectors which incorporated genes of their choosing and used the new vectors to insert these genes into the DNA of living organisms. Genetic engineers believe they can improve the foods we eat by doing this. For example, tomatoes are sensitive to frost. This shortens their growing season. Fish, on the other hand, survive in very cold water. Scientists identified a particular gene which enables a flounder to resist cold and used the technology of genetic engineering to insert this 'anti-freeze' gene into a tomato. This makes it possible to extend the growing season of the tomato

Techniques

Living cells contain minute threadlike structures called chromosomes which contain deoxyribonucleic acid or DNA, shaped like double helix. The base or rungs of this twisted ladder-like structure constitute the genes which store information determining the characteristics of an organism. The DNA molecule lends itself for easy replication as enzymes can split up the base sequence of its double helix thus producing identical pairs. Genetic engineering is performed by technicians using high-powered microscopes and micro surgical instruments. Genetically engineered microorganisms are created using a technique called gene splicing, or gene cloning. In this technique, segments of DNA are cut out of a cell (called a donor cell) from an organism and inserted into the DNA of a vector. A vector is usually a plasmid, a circular structure extracted from a bacterium and containing some of that bacterium's DNA; in some cases, the vector is a modified virus. The vector, with the combined DNA, is then inserted into a cell (called a host cell) from a species different from that of the donor cell. Once in the host cell, the DNA makes exact genetic copies, or clones, of itself. Sometimes, special enzymes called restriction enzymes are used to isolate gene-sized DNA fragments which break the given molecule by creating a cleavage at particular points on the base sequence of its DNA. With the help of the enzyme ligate the fragments are then joined or spliced with other DNA structures thus producing recombinant DNA molecules. When combined with other cells these recombinant DNA molecules transform the latter and lead to the creation of colonies made up of millions of cells with newly added genetic information. This process leads to the creation of clones or groups of genetically identical cells

Fundamental Weaknesses of the Concept

Imprecise Technology—A genetic engineer moves genes from one organism to another. A gene can be cut precisely from the DNA of an organism, but the insertion into the DNA of the target organism is basically random. As a consequence, there is a risk that it may disrupt the functioning of other genes essential to the life of that organism.

Side Effects—Genetic engineering is like performing heart surgery with a shovel. Scientists do not yet understand living systems completely enough to perform DNA surgery without creating mutations which could be harmful to the environment and our health. They are experimenting with very delicate, yet powerful forces of nature, without full knowledge of the repercussions.

Widespread Crop Failure—Genetic engineers intend to profit by patenting genetically engineered seeds. This means that, when a farmer plants genetically engineered seeds, all the seeds have identical genetic structure. As a result, if a fungus, a virus, or a pest develops which can attack this particular crop, there could be widespread crop failure.

Threatens Our Entire Food Supply—Insects, birds, and wind can carry genetically altered seeds into neighboring fields and beyond. Pollen from transgenic plants can cross-pollinate with genetically natural crops and wild relatives. All crops, organic and non-organic, are vulnerable to contamination from cross-pollination.

Health Hazards

No Long-Term Safety Testing—Genetic engineering uses material from organisms that have never been part of the human food supply to change the fundamental nature of the food we eat. Without long-term testing no one knows if these foods are safe.

Toxins—Genetic engineering can cause unexpected mutations in an organism, which can create new and higher levels of toxins in foods.

Allergic Reactions—Genetic engineering can also produce unforeseen and unknown allergens in foods.

Decreased Nutritional Value—transgenic foods may mislead consumers with counterfeit freshness. A luscious-looking, bright red genetically engineered tomato could be several weeks old and of little nutritional worth.

Antibiotic Resistant Bacteria—Genetic engineers use antibiotic-resistance genes to mark genetically engineered cells. This means that genetically engineered crops contain genes which confer resistance to antibiotics. These genes may be picked up by bacteria which may infect us.

Problems Cannot Be Traced—without labels, our public health agencies are powerless to trace problems of any kind back to their source. The potential for tragedy is staggering.

Side Effects can kill—37 people died, 1500 were partially paralyzed, and 5000 more were temporarily disabled by a syndrome that was finally linked to tryptophan made by genetically-engineered bacteria.

Environmental Hazards

Increased use of Herbicides—Scientists estimate that plants genetically engineered to be herbicide-resistant will greatly increase the amount of herbicide use, knowing that their crops can tolerate the herbicides, will use them more liberally.

More Pesticides—GE crops often manufacture their own pesticides and may be classified as pesticides by the EPA. This strategy will put more pesticides into our food and fields than ever before.

Ecology may be damaged—the influence of a genetically engineered organism on the food chain may damage the local ecology. The new organism may compete successfully with wild relatives, causing unforeseen changes in the environment.

Gene Pollution Cannot Be cleaned Up—Once genetically engineered organisms, bacteria and viruses are released into the environment it is impossible to contain or recall them. Unlike chemical or nuclear contamination, negative effects are irreversible.

DNA is actually not well understood. 97% of human DNA is called junk because scientists do not know its function. The workings of a single cell are so complex; no one knows the whole of it. Yet the biotech companies have already planted millions of acres with genetically engineered crops, and they intend to engineer every crop in the world.

The concerns above arise from an appreciation of the fundamental role DNA plays in life, the gaps in our understanding of it, and the vast scale of application of the little we do know. Even the scientists in the Food and Drug administration have expressed concerns.