Modern genetic technology can be used to modify the genomes of living beings. This process is also known as “genetic engineering”.
The genes of a species can be modified or they can be transplanted from one species to another. Genetic engineering is possible thanks to recombinant DNA technology.
Organisms that have altered genomes are known as transgenic. Most transgenic organisms are generated in the laboratory for research purposes.
For example, “knock-out” mice are transgenic mice that have a particular gene of interest disabled. By studying the effects of the missing gene, researchers can better understand the normal function of the gene.
Transgenic organisms have also been developed for commercial purposes. Perhaps the most famous examples are food crops such as soybeans and corn that have been genetically modified for resistance to pests and herbicides.
These crops are widely known as “GMOs” (genetically modified organisms).
Here are some other examples of transgenic organisms with commercial value:
Golden Rice: Modified rice that produces beta-carotene , the precursor of vitamin A. Vitamin A deficiency is a public health problem for millions of people around the world, particularly in Africa and Southeast Asia. Golden rice still awaits regulatory approval.
Goats that produce important proteins in their milk: Goats modified to produce FDA-approved human antithrombin (ATryn), which is used to treat a rare blood clot disorder in humans.
Goats have also been genetically modified to produce spider silk, one of the strongest materials known to man, in their milk. Proposed uses for this range of recombinant spider silk from artificial tendons to bulletproof vests.
Plantains producing vaccines: genetically modified bananas that contain a vaccine. Bananas provide an easy means to administer a vaccine (especially to children) without the need for a medical professional trained to inject. Edible vaccines are still in development.
Chymosin-producing microorganisms: Yeast, fungi or bacteria modified to produce the enzyme chymosin, which divides milk to make cheese. Traditionally, rennet (found in the stomachs of cows) is used to coagulate cheese.
But, when the demand for firm cheeses exceeded the amount of rennet available, recombinant chemosin was developed and is widely used today.
Blue Roses: Roses modified with thoughts genes to express a blue color. The Japanese company Suntory developed the blue rose, which was previously unattainable through traditional selective breeding approaches. Before the success of Suntory, blue roses were created by dyeing techniques.
A more practical objection to transgenic technology is the risk of altering ecosystems. Consider genetically modified Atlantic salmon, currently under review by the US Food and Drug Administration. UU (FDA).
The fish have a growth hormone gene taken from Chinook salmon and a DNA sequence that controls the expression of the gene taken from ocean distemper, a fish that produces the hormone throughout the year.
Because Atlantic salmon normally produce growth hormone only during the summer, the transgenic animal grows more than twice the natural rate.
Such genetically modified salmon could escape from farms where they are intended to breed and invade natural ecosystems, where they can compete with native fish for space, food and couples
Until recently, the fear that a transgenic organism could escape and infiltrate a natural ecosystem was based on theoretical scenarios. For example, a 1999 report of transgenic corn pollen damaging monarch butterfly larvae in a laboratory simulation was not confirmed by larger and more realistic studies.
But in 2001 it was discovered that transgenic corn grew on remote mountain peaks in Mexico, ironically in the area where most of the natural variants of corn originated. It was assumed that corn could not extend beyond the fields where it was grown.
Approximately at the same time, 10,000 hectares (24,700 acres) of transgenic cotton were found in India. A farmer had crossed transgenic cotton that he had obtained from the United States with a local variant and planted crops, without realizing that he had used a genetically modified product.
Currently, US consumers can not tell if a food contains a genetically modified product or not, because two thirds of processed foods that include GMOs and that are sold in the United States have not been labeled.
This lack of labeling is consistent with existing regulatory practice.
While the FDA tests food to determine its effect on the human digestive system, its biochemical composition and its similarity to existing foods (using a guiding principle called substantial equivalence), foods are not judged solely by their origin.
For example, the FDA denied the commercialization of a potato derived from traditional selective breeding.
How are organisms modified?
Now that you know what a transgenic organism is, let’s talk about how we create these new organisms. There are different ways of doing this, but in general the process involves taking genes from one organism and putting them into another in ways that would not occur naturally.
Bacteria are often used to grow and reproduce the desired genes. Bacteria are excellent for this because they grow and reproduce quickly and can be controlled quite well in the laboratory.
An example of this is the production of insulin. Insulin is a hormone that is normally produced in the human pancreas. Those who are diabetic can not do it, and another source is needed to treat these patients. The insulin gene is isolated, inserted into the bacteria, produced at a rapid rate and then extracted to give it to diabetics.