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Application of Genetically Modified Organisms
#1
A genetically modified organism is an organism whose genetic material or sequence has been altered. They are the sources of genetically modified foods. Genetic alteration can occur naturally or artificially. Naturally, genetically modified organisms occur as an impact of other factors apart from human will. For instance, the penetration of a gene into a foreign cell could result to development of a naturally genetically modified organism. Artificially, genetically modified organisms have been developed depending on desired characteristic. Numerous genetic engineering techniques have been developed and used in the development of these genetically modified organisms. These techniques which are based on circumstances which could occur naturally include; deletion, insertion and mutation of specific genes. Some organisms whose genetic makeup has been successfully modified include bacteria, yeasts, plants, fish and mammals. Other than food, genetically modified organisms have been used in the production of other commercially products like proteins.

Genetic engineering has accrued numerous benefits. They provide excellent tools for medical and biological researches. Deletion, insertion or mutation of certain genes to an organism gives insight to the function of these genes. Another commonly used and powerful tool is the use of promoters. Promoters cause an over expression of a gene of a group of genes. The phenotypes formed as a result of manipulating these genes enable researchers to determine the functions of the genes in question. Microorganisms, particularly bacteria were the first organisms to be manipulated due to their simple and well know genetic makeup. Genetically modified bacteria have numerous benefits. For instance there has been production of large amounts of commercially viable human proteins that is used in production of medicine. Insulin, a protein used to treat diabetes has been easily produced by these bacteria. Human growth hormone, used to treat dwarfism has also been produced. Other genetically modified organisms have been used in production of enzymes and clotting factors. For instance, a drug Atryn, an anticoagulant has been obtained from the milk of a genetically modified goat.

Out of genetic engineering, pharmaceutical drugs have been developed. Organisms that are of medicinal value have been cultivated in bioreactors rather than in the fields. Proper examples include; Chlamydomonas reinhardtii which is an alga and Physcomitrella patens which is a moss. Cultivating of organisms in bioreactors allows close monitoring so as to provide the required results. Other genetically modified organisms have been used as models in researches that are vital in the development and establishment of treatments for different ailments.


In agriculture, crops with better traits like yield, vigor and resistance to pests and diseases have been developed through genetic engineering. A good example is the genetically modified papaya grown in Hawaii. This papaya is resistant to the Ring spot virus and it also produces the Bacillus thuringiensis toxin which is considered not harmful to human but plays a great role as an insecticide. Crops have been engineered to produce greater yield with longer shelf life. Plants for instance corn and the poplars have been genetically modified and used to produce biofuel which have been used as an efficient substitute of petroleum products. There is development of animals with traits that are desirable compared with their natural counterparts. For example, Yorkshire pigs have been genetically modified to produce a type of pig that digests plant phosphorus. They are capable of producing enzyme phytase in their saliva, which digests phosphorous unlike their counterpart pigs.

Notably, these are just some of the many achievements accrued through genetic engineering. However, the disadvantages and negative impact of genetically modified organisms to human and the environment cause great controversies over the technology. Especially genetically modified foods have caused controversies whether they are safe for human consumption and whether they are should be used to address the needs of food worldwide. Here, some major disadvantages of genetically modified organisms and food stuffs are discussed.

Genetically modified corn has been suspected to be toxic. This disapproves claims that there is no difference between genetically modified and normal corn. Studies show that some elements absent in normal corn have been detected in the genetically modified corn in relatively high quantities. These include; glyphosate, formaldehyde and chloride which are potentially toxic. Although formaldehyde and chloride are potentially lethal, great interest has been bestowed on glyphosate. Glyphosate, organic phosphate is known to immobilize elements such as copper, zinc, iron, cobalt and manganese. These are some of the major elements required for vital physiological processes in animals, plants and soil. Glyphosate has been revealed to coat the genetically modified corn. It could be argued that this could be a major cause of certain cell disorders when it immobilizes other elements in the cell.

Genetically modified foods have been associated with development of allergy from foods that previously did not cause elegy previously. For example, if a person with a known allergy to beef takes pork that has a gene derived from cattle, considerably, the person would suffer allergy complications. This has put human health at risk especially where the ingredients of food stuffs are not well labeled. Equally, these foods have been related to the increased development of tumors and cancer in human beings. For instance, GH, is an hormone that when injected to the pituitary gland of a cow leads to increased production of milk. However, this protein hormone increases the level of IGF, a chemical that causes breast and colorectal cancer.

Another negative impact of genetically modified organism, specifically corn, has been expressed in the Bt corn. This corn was developed by insertion of a gene from Bacillus thuringiensis into its genome to express a toxin which is lethal to insect pests. It is favorable to many non target organisms such as pollinators and human beings. However, the bacteria genes have caused the plant to produce crystalline pollen grains which are toxic to other plants. Greatly affected are the monarch caterpillars which feed on the milkweed that grow around field corns. As a result of feeding on the milkweed dusted with toxic pollen, the caterpillars have been found to suffer higher mortality rates and slow growth rate. Other pests have been found to undergo faster rate of evolution and mortality rate as a response to increased toxicity in the corn fields. Notably, the massive disappearance of bees which are efficient pollinators can be related to the presence of genetically modified pollen in the fields. This as a result has led to loss of original species of different organisms.

As much as genetic engineering is very beneficial, it is recommended that, before authorization of any genetically modified product, all the pros and cons should be critically evaluated.
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#2
A transgenic animal contains in its genome a gene or genes introduced by one or the other technique of transfection. The gene introduced by transfection is called transgene. In animals, transfection species the introduction of a DNA segment, either naked or integrated into a vector, into an animal cell. The same phenomenon is known as transformation in all other organism.

Transfection may be transient or permanent (stable). In transient transfection, the introduced gene is gradually lost from the daughter cells of transfected cells. But in case of stable transfection, the introduced gene is retained and expressed in all the cells derived from the transfected cells. Since most of the animal vectors are unstable, i.e., are gradually lost, in the extra chromosomal state, stable transfections are ordinarily due to the integration of introduced gene into the cell genome.

Transgenics have been produced in a variety of animal species, e.g., mice (including rats), rabbits, swine, sheep, goat, cattle, poultry, fish, amphibians, insects and nematodes. However, these activities are so far limited to experimental stages, and production technologies based on transgenic animals have not yet reached commercial applications. Below are a few examples of transgenic animals:

1. Transgenic Mice

Mouse is the most preferred mammal for studies on gene transfers due to its many favorable features like short estrous cycle and gestation period, relatively short generation time, production of several offspring per pregnancy (i.e. litter), convenient in vitro fertilization, successful culture of embryos in vitro at least for a period of time, production and maintenance of ES cell lines, availability of a diverse array of genetic stocks, etc. As a result, the techniques for gene transfer and transgenic production have been developed using mice as models; subsequently, these approaches have been modified to adapt them to other animal species.

2. Transgenic Rabbits

Rabbits are quite promising for gene farming or molecular farming, which aims at the production of recoverable quantities of pharmaceutically or biologically important proteins encoded by transgenes. Transgenic animals used for this purpose are popularly called bioreactors. Generally, the transgenes are designed to be expressed in mammary tissue so that their protein products are secreted in milk. Consequently, the protein product is easily harvested with milk from which it is conveniently purified. The following human genes encoding valuable proteins have been separately transferred into rabbits; interleukin 2, growth hormone, tissue plasminogen activator, antitrypsin etc. In addition, bovine lactalbumin has also been expressed. These genes were expressed in the mammary tissues and their proteins were harvested from milk.
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