Transgenic organisms.pptx (Size: 1.04 MB / Downloads: 40)
A transgenic organism is an organism that has been genetically engineered.
It has genes from more than one organism.
A transgenic organism contains a gene or genes which have been artificially inserted instead of the organism aquiring them through reproduction
A genetically modified organism (GMO) or genetically engineered organism (GEO) is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one molecule to create a new set of genes. This DNA is then transferred into an organism, giving it modified or novel genes.Transgenic organisms, a subset of GMOs, are organisms that have inserted DNA from a different species. GMOs are the constituents of genetically modified foods.
There is no such disadvantages of genetically modified organisms proved on a scientific point of view. But they are always under ethical misjudgment. However some disadvantages can be pointed out-
Genetic modifications results in formation of Transgenic plants and animals. So there may be a chance of loss of Genetic diversity upon wide use of this process on particular species, if care is not taken to preserve genetic material of the original organisms.
Artificial Genetic modifications of a desired organism may results in simultaneous Natural Genetic (or other) modifications of a undesired organism. For example, on modifying a plant to be resistant to a particular disease causing organism, the latter may acquire natural variations which may enable it to infect other plant species not previously infected.
Some people complain that by modifying different agricultural plants to increase quantity, resistance etc. the natural taste of the food product is somehow get disrupted. However, it has no scientific basis.
Advantages:1- Improvement of crops (improving some characteristics which are plant weaknesses. For example production of insect tolerance plants)
2- Increasing the production ( that could be either increasing the yield or one/more compounds in a plant (especially medicinal plants) for example : the sheep gives us more wool
Why are transgenics important?
The underlying principle in the production of transgenic animals is the introduction of a foreign gene or genes into an animal (the inserted genes are called transgenes). The foreign genes “must be transmitted through the germ line, so that every cell, including germ cells, of the animal contain the same modified genetic material.”26 ( Germ cells are cells whose function is to transmit genes to an organism’s offspring.)
METHOD OF TGO
To date, there are three basic methods of producing transgenic animals:
Retrovirus-mediated gene transfer
Embryonic stem cell-mediated gene transfer
The mouse was the first animal to undergo successful gene transfer using DNA microinjection.
This method involves:
Transfer of a desired gene construct (of a single gene or a combination of genes that are recombined and then cloned) from another member of the same species or from a different species into the pronucleus of a reproductive cell .
The manipulated cell, which first must be cultured in vitro (in a lab, not in a live animal) to develop to a specific embryonic phase, is then transferred to the recipient female
what are transgenic animals used for ?
Transgenic animals are used as experimental models to perform phenotypic tests with genes whose function is unknown or to generate animals that are susceptible to certain compounds or stresses for testing in biomedical research. Other applications include the production of human hormones, such as insulin.
Frequently used in genetic research are transgenic fruit flies (Drosophila melanogaster) as genetic models to study the effects of genetic changes on development.Flies are often preferred over other animals for ease of culture, and also because the fly genome is somewhat simpler than that of vertebrates. Transgenic mice are often used to study cellular and tissue-specific responses to disease.
Biomaterials are materials mainly used in the medical area, and have been applied in the dental field, surgery, and drug delivery. The first priority for biomaterials is biocompatibility with the host tissues to which they have been applied. The shortage of organs to be transplanted is a worldwide problem, and many patients die before they can get a suitable organ replacement; even after transplantation, some patients die due to mis-compatibility. A promising future for solving this problem may be found in the use of GMOs to generate biomaterials, by using transgenic animals which are able to provide large quantity of organs biocompatible to the receivers.
Traditional methods of producing protein drugs and vaccines in mass quantities are very time-consuming and expensive. GMOs, such as transgenic bacteria or yeast, can produce large quantities of those drugs and vaccines in a much more efficient way (3). Therefore, mass application of GMOs in pharmacy has allowed large quantity of originally expensive new drugs to put into the market in a shorter time span and at a much lower price.
GMOs used in this field are mainly transgenic plants that are resistant to pests, herbicides or harsh environmental conditions, have improved shelf life, and increased nutritional value. For example, the transgenic plant producing Bt Toxin (Figure 2), an insecticide originally produced by the bacterium Bacillus thuringiensis with specific activities against many species of pest insects (4), entered the commercial market within in the last decade. Many transgenic plants, such as genetically modified soybeans and corns with higher nutritional values or better taste, have already entered many people’s daily lives.