Genetic engineering

The invention of DNA and Mendel’s experiment cemented the path of future of genetic engineering (GE). GE is the direct stage management of an organism’s genes by technological intervention. Today’s applications of GE are the result of many significant developments in the understanding of the science of genetics and development of technology to alter genes. The history of modern GE begins in 1880 with the work of Gregor Mendel, the father of genetics. Through his work with pea plants, Mendel derived the groundwork of modern genetics.

He found that characteristics are transmitted in discrete units or genes; the presence of genes in the organism dictates the expression of certain qualities in the organism. Hershey and Chase proved that deoxyribonucleic acid (DNA), is the genetic material of the cell. In 1953, Watson and Crick discovered the double helical structure of DNA. Later in the 1960’s, scientists cracked the genetic code and developed the central creed of genetics: DNA, RNA and protein. In the 1970s, scientists developed the fundamental techniques of GE. In the early 1970s, scientists discovered restriction enzymes.

GE involves changing the genetic constitute of an organism. The central precept of GE is the understanding that changing the genes of an organism changes it’s physical attributes and it can be used to produce organisms with desired physical attributes through direct genetic intervention. GE is a laboratory technique used by scientists to change the DNA of living organisms. GE is used to take genes and segments of DNA from one species and then to put it in the other species. GE provides a set of techniques to cut DNA either randomly or at number of specific sites.

Once isolated we can study different segments of DNA, multiply them and stick them next to another DNA of another cell or organism. GE makes it possible to get through the species obstacle and to hobble the genetic information between completely irrelevant species. GE can also be described as the techniques of plant and animal breeding to modify characteristics of animals. In agriculture, the concentrate has been mainly on the increased productivity or breeding for characteristics which the costumers were interested to buy. The conventional way of plant breeding usually occurs within species.

DNA is distinct for each organism and contains all the genetic information. All biochemical processes relies on the information stored in DNA. The segments of DNA, which have been linked with specific features, or functions of an organism are called genes. DNA molecule (plasmid, virus, bacteriophage, artificial or cut DNA molecule) able of replication and bearing cloning sites for the introduction of foreign DNA, used to introduce this DNA into the host cells is known as vector. Biologists have found that there are many enzymes that can read the sequence of DNA and they can cut and stick the DNA strands.

Plasmids are the vectors and are found in many bacteria. They are small rings of DNA with the restricted amount of genes and often contains genes of antibiotic resistance. Plasmids are small, and they are able of replicating speedily and easy to manipulate. Sequences are easy to find with the help of enzymes. These enzymes are termed as restriction enzyme. In order to splice a gene the first step would be to isolate plasmid from cells in a test tube then add a restriction enzymes that cuts the plasmid from the specific site.

Then purify the cut plasmid and mix it with the gene. After sometime the gene places itself into the cut ring of the plasmid. Then one should add enzyme ligase and place the mended plasmid back in the bacteria that are left to grow. To know that the bacteria that are multiplying contains plasmid of our interest or not one needs marker genes that are antibiotic resistance genes. Before we let the bacteria to multiply we should make sure that the plasmid contains marker gene, so that we can add specific antibiotic to food supply of the bacteria.

All the bacteria not having plasmid will die and those having plasmid will multiply in the culture medium of the fermenter. http://www. med. nus. edu. sg/life_sciences/principle. htm Polymerase chain reaction is another technique by which DNA can be synthesized. PCR is a process based on the ability of a DNA polymerase enzyme that can synthesize a complementary strand to a targeted segment of DNA in a test tube mixture of the four DNA bases. In addition, the mixture must also contain two DNA fragments, each about 20 bases long, called primer.

The 20-25 base pair sequence will be unique in the entire human genome. To insert a piece of foreign DNA, the vector is first cut off with the help of restriction enzyme and the foreign DNA pasted by using enzyme ligases. The vector-inserted DNA is now called recombinant DNA. This recombinant DNA has the ability to replicate inside bacteria cells and as the cells reproduce, many more bacteria will be reproducing the same DNA. These DNA are known as “clones”, sharing the same parent and have identical sequences. GE has become the part of our life.

Their applications are in all the biological fields. It can be applied in medicine, plants, animals, human hormones, etc. It increases the rate of productivity in plants or can increase the resistance power of plants against insects and pests. There can be transformation of gene from plants to animals and vice-versa. http://www. contexo. info/DNA_Basics/polymerase_chain_reaction. htm The application of GE in plants likes tomatoes, which are very sensitive to frost and shorten their growing season. Fishes are opposite to a tomato that is that they survive in cold water.

In order to increase season for tomatoes to survive scientist thought to find that particular gene, which is resistance to cold water in fish and then insert it in the DNA to tomato using the gene technology. By inserting this anti-freezing gene the scientist extended the growing season of tomatoes. Various insect pests, such as the boll budworm, the tobacco budworm, and the pink bollworm, plague Cotton farmers. The bacterium produces a toxin that is deadly to caterpillars like the three mentioned and are harmless to everything else.

Bt cotton was among the first transgenic crops to be used in commercial agriculture. So genetic engineers transferred the gene for Bt toxin from Bacillus thuringiensis to cotton. A gene from the soil bacterium Bacillus thuringiensis (Bt) has been transferred to the cotton genome. This gene codes for production of a protein that is toxic to the cotton bollworm, a severe insect pest in most cotton-growing regions of the world. The gene for Bt toxin has been transferred into several other crops. The application of GE in medicines plays vital role in human life.

GE is making this a reality by using monoclonal antibodies against tumours although the work is still very experimental . The idea is that the antibody will travel harmlessly in the body until it finds the cancer cells to be destroyed. Once this happens, the antibody sticks to the cancer cells, releases a cell poison of some description, or radioactivity, and the cancer cells die. This can cure cancer. Haemophilia is a disease that cannot produce fibrins to stop internal blood bleeding. For some haemophiliacs, injections of Factor IX, a blood-clotting protein, can reduce symptoms caused by haemorrhaging.

This treatment cannot remove the risk completely. This is a hereditary disease. Gene therapy for haemophilia is designed to repair a faulty gene so the body produces blood-clotting factor on its own. Some people have undergone this treatment and have corrected the DNA defaults. There are some side effects of GE. Scientists do not yet understand living systems completely enough to perform DNA surgery without creating changes, which could be adverse to the environment and our health. They are experimenting without complete knowledge.

Science has brought us to the point where we can transfer genes from one species to another, so that we can change the traits of agricultural crops. If these changes are done with care, we can have crops which are more productive, nutritious, tastier, and better for the environment. It is also possible to proceed carelessly and do damage to the environment and to people’s health. The objective record so far is that the scientists developing transgenic crops have been responsible. In agriculture there are many problems of using pesticides instead it is better to use transgenic plants.

Many farmers used to die due to toxic effects of pesticides. Even the rivers and streams used to get polluted with the harmful chemicals. Thus transgenic plants eliminate danger. Biotechnology can be used both for good and evil purposes. Using biotechnology new bacteria and viruses can be produced which cannot be treated. But biotechnology can also change our lives. Two trees: American chestnut and the American elm. A fungus then infected the trees. Many of these chestnut trees are still alive as roots, but they never grow to maturity before they grow fungus reinfects.

Elm trees are highly susceptible to a different fungus, carried by a beetle. Few elm trees have survived. Scientists have transferred genes into elm trees that should make them immune to the elm fungus. Biotechnology has both side some harmful effects and some good effects. But if people do not misuse it GE can change the whole world. In my opinion people should support GE, which can make true all the imaginary thoughts. It will bring a great revolution and there will be no incurable diseases. People can be provided with good facilities as all the fruits, vegetables etc. would be able to grow all over the world.

Reference

http://www.iupac.org/goldbook/V06606.pdf

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