Genetic engineering is the alteration of genetic code by artificial
means, and is therefore different from traditional selective breeding.
Genetic engineering (GE) is used to take genes and segments of DNA
from one species, e.g. fish, and put them into another species, e.g.
tomato. To do so, GE provides a set of techniques to cut DNA either
randomly or at a number of specific sites. Once isolated one can study
the different segments of DNA, multiply them up and splice them (stick
them) next to any other DNA of another cell or organism. GE makes it
possible to break through the species barrier and to shuffle
information between completely unrelated species; for example, to
splice the anti-freeze gene from flounder into tomatoes or
strawberries, an insect-killing toxin gene from bacteria into maize,
cotton or seeds, or genes from humans into pigs.
HOW GENETIC ENGINEERING IS CURRENTLY USED
Here is a brief summary of some of the more important, recent
developments in genetic engineering.
1) Most of the genetic engineering now being used commercially is in
the agricultural sector. Plants are genetically engineered to be
resistant to herbicides, to have built in pesticide resistance, and to
convert nitrogen directly from the soil. Insects are being genetically
engineered to attack crop predators. Research is ongoing in growing
agricultural products directly in the laboratory using genetically
engineered bacteria. Also envisioned is a major commercial role for
genetically engineered plants as chemical factories. For example,
organic plastics are already being produced in this manner.
2) Genetically engineered animals are being developed as living
factories for the production of pharmaceuticals and as sources of
organs for transplantation into humans. (New animals created through
the process of cross-species gene transfer are called xenographs. The
transplanting of organs across species is called xenotransplantation.)
A combination of genetic engineering and cloning is leading to the
development of animals for meat with less fat, etc. Fish are being
genetically engineered to grow larger and more rapidly.
3) Many pharmaceutical drugs, including insulin, are already
genetically engineered in the laboratory. Many enzymes used in the
food industry, including rennet used in cheese production, are also
available in genetically engineered form and are in widespread use.
4) Medical researchers are genetically engineering disease carrying
insects so that their disease potency is destroyed. They are
genetically engineering human skin9 and soon hope to do the same with
entire organs and other body parts.
5) Genetic screening is already used to screen for some hereditary
conditions. Research is ongoing in the use of gene therapy in the
attempt to correct...