about genetically modified food

The definition

Genetically Modified (GM) foods are produced from

genetically modified organisms (known as GMO) which have had their

genome changed through using genetical techniques.

GMO is produced by inserting DNA taken from another organism

and modified into an organism's genome.

GM food had been produced because of having advantages like being resistance to drought, insect infestation, disease, and make the final food product rich in vitamins and minerals, larger, tastier, or have a longer shelf life.

GM food can be distinguished between :

-- a whole GM organism

(soya bean with bacterial gene)

-- a processed GMO

(tofu made from GM soya bean)

-- byproduct of a GMO

(oil or lecithin from a GM soya bean)

_________________________________________

TYPES OF GENETICALLY MODIFIED FOOD

GM food can be plant, animal, human or bacteria source.

For plant source

Tomatoes: In 1992 the FDA announced the Flavr Savr tomato. The tomatoes were modified by a biotech company named Calgene. The company produced a tomato that was allowed to ripen on the vine longer and still retain their firm skin when they make it to the supermarket. Traditional tomatoes were picked off the tomato vines green and a chemical was applied to turn them red.


Corn: BT corn was introduced in 1996. The difference between BT corn and non-BT corn is that BT corn produces it's own insecticide to guard against the European Corn Borer. Non-BT corn is susceptible to the European Corn Borer and this caused a yield loss of 5-10 percent annually across the nation. The introduction of BT corn has lead to increased yield and a lower price for consumers.


Soybeans: Roundup Ready soybeans have been on the market since 1996. This type of soybean plant allows farmers the ability to spray a broad spectrum herbicide on their fields throughout the plants life. This eliminates the need to use several herbicides at different stages of the soybeans life. This saves the farmers money and that gets passed on to the consumers.


Potatoes: There are two different kinds of potatoes that have been genetically modified. One kind of potato has an increased resistance to pests and diseases that are common to potato plants. They have a resistance to diseases and loss caused by nematodes, viruses, fungi, bacteria, insects, and herbicides. The other kind of potato has an improved storage and processing characteristic. Some of the improvements to this potato is a decreased vulnerability to bruising and a changed starch content that allows for more efficient industrial starch processing.

___________________________________________

For animal source,
one great example is "dolly the sheep" whic is born through cloning, one of the types of genetically modified methods.

There are three types of "modern" genetic engineering that can be used on animals. Modern being the use of chemicals instead of just selective breeding.

Xenografting-
The use of human DNA to supplement an animal's or vice versa.
For example, animal valves and tissue have been used in humans. Humans have successfully received pig valves and hearts. The genetics involved with this were much simpler and the scientists learned by what worked, they did not know exactly why things worked. It turns out the DNA of pig heart valves was similar enough to humans that they were interchangeable under some circumstances. The next step, which has not yet reached the stage of clinical trials, was to make pigs grow human hearts that were coded by the DNA from humans.

Cloning-
Using the DNA of one animal to another animal with the identical genetic makeup.
For example, inserting the DNA of one animal into the fetus of the same species along with a vector which gets cleans out the DNA already in the embryo. Sometimes the vector does not get rid of the original DNA of the fetus or the fetus does not adopt the new DNA.

Manipulation-
The changing of animal DNA.
For example, human insulin can be produced from the engineering that can be used to treat diabetes. Pigs hearts that have enough human characteristics to keep from being rejected by humans had been used, from the research conducted at Dartmouth and Duke University. These pigs would be used for heart and valve transplants.

________________________________________________

For bacteria source

Genetically modified on bacteria can be done by a clone of bacteria which is all containing the gene of interest in a short period. The cells can then be lysed and DNA can be isolated in short order. Bacteria are routinely used to produce non-bacterial proteins.

An example is the production of purified proteins for vaccine use.

source:

definition-->

http://en.wikipedia.org/wiki/Genetically_modified_food

plant source-->

http://www.utm.edu/staff/tdodson/gmcrops.htm

animal source-->

http://www.govhs.org/vhsweb/Gallery.nsf/Files/Genetic+Engineering,+a+group+project/$file/animal.html

bacteria source-->

http://www.learner.org/channel/courses/biology/textbook/gmo/gmo_2.html