What is Transgenic food? what are the advantages and disadvantages of transgenic food?

Answer 1

We have some altered crops in the US expressing genes for either herbicide tolerance (HT) or Bt for insect resistance for crop protection. The crops include corn, cotton, soybeans, and canola. HT allows farmers to use a glycophosphate herbicide sprayed directly onto the crop plant but only kill the weeds. Bt comes from the bacteria Bacillus thuringiensis. Bt is a catch all name for an entire bacterial genus that each attacks a different host insect. Putting a Bt protein in the plant lets the plant fight the specific insect that eats it. This lets farmers use fewer broad spectrum pesticides.
In sunflowers the pollen has already hybridized with wild sunflowers that are now much more hardy since they have an ability to resist their predators. "A Bt transgene reduces herbivory and enhances fecundity in wild sunflowers." Ecological Applications 13: 279-86.

Engineered Crops pose ~4 kinds of potential risks.
1a Crop escapes as weed
1b Crop hybridizes with wild versions (weedy types)
2 Viral vector is altered/repaired to escape bearing its insert
3 Crops gene insertion is toxic to unexpected organism
4 Crop diversity will diminish.

It is possible to add nutritional extras to particular crops to benefit people. Flavor and color can be altered also.
Another potential benefit is medical
Crops can have attenuated viral coat proteins included to provide a cheap, easily stored & delivered oral immunity.
http://www.geocities.com/plantvaccines/transgenicplants.htmimmunize

Crops could be altered to be xeric, water efficient. These would be of use in dry climates.

Chymosin is not in a crop plant but in a bacteria. The bacteria are harvested and the enzyme is purified to be used to replace calf rennet in cheese making.
http://www.ctahr.hawaii.edu/gmo/risks/benefits.asp

Answer 2

Transgenic foods are scientifically altererd food. Transgenic foods can have stay fresher longer, or for example they make strawberries not freeze up in the winter by inserting DNA of a gene that is not included naturally in the food or in the crop.

It can make food more abundent for people in other countries who can't grow enough food to feed everyone in there country, but not enough research has been done on transgenic foods to really know if it is truly safe to comsume.