GMOs: Structure, Transgenic Organisms, Labeling, and Applications
DNA Structure and Transgenic Organisms
DNA Structure
The structure of DNA is a double helix of two antiparallel strands. It is composed of nucleotides (deoxyribose, phosphate, and nitrogenous bases).
Transgenic Organisms
A transgenic organism is a living being into whose genome the genetic material of another living organism has been introduced. These organisms are artificially created by manipulating their genes. Eukaryotic organisms, such as plants or animals, that have been modified by genetic engineering are called transgenic organisms.
Transgenic Plants
Examples include soybean and GM maize. A variety of GM maize has been grown in Spain since 1998. The maize genome has incorporated a gene from a bacterium (Bacillus thuringiensis) that produces a substance poisonous to certain pests. The larvae that attack these transgenic maize plants die from intoxication.
Transgenic Animals
In 2001, the first animal for human consumption was patented: a salmon that grows six to eight times faster than normal salmon. The genome of these giant salmon contains two introduced genes: one from the Arctic flatfish, which does not stop growing during winter, and a modification of a salmon gene that does not interrupt the creation of growth hormone when the fish reaches maturity.
Organisms and Insulin Production
One of the first successful applications of transgenic organisms was introducing the gene for human insulin into the DNA of bacteria, causing the bacteria to produce insulin.
Creating a Transgenic Organism
First Stage
- Isolate the desired gene from another plant, bacterium, virus, or animal.
- Modify the gene, as it cannot be directly inserted. Wrap the DNA around the plant to resemble the plant’s DNA.
- Introduce the modified gene into the nucleus of the cell using a vector such as a virus or bacterium. Also, introduce a marker gene that confers resistance to an antibiotic, which is used to select transformed cells.
- Grow the cells in a medium with the antibiotic to ensure that the cells have incorporated the gene.
Second Stage
Obtain plants or animals from the modified cell’s genome.
Food Labeling of GMOs
In April 2004, new European regulations came into force, requiring that the packaging of products containing GMOs or made from them must specify this, even if the ingredient is minimal. This information is required if the food is:
- A transgenic food
- A product containing GMOs
- A food produced from transgenic organisms
Exceptions are made for:
- Foods containing only 0.9% GM
- Products of the second or third generation
- Food employing transgenic microorganisms for fermentation
Applications and Risks of GMOs
Biotechnology involves the use of living organisms or their products for commercial and industrial purposes. Modern biotechnology makes widespread use of GMOs, and their applications cover different areas:
- Food Industry: Obtaining foods with specific characteristics, such as baby rice or meat low in cholesterol, and improving the efficiency of industrial processes like making bread or beer, in which microorganisms are involved.
- Pharmaceuticals: Production of pharmaceuticals or vaccines, such as animals whose milk contains a blood-clotting factor, or bacteria that have been incorporated with human genes and can produce insulin and human growth hormone.
- Agriculture and Livestock: Improved agronomic traits such as resistance to herbicides or pests in plants, and increased production of milk or meat.
- Environment: Toxic waste disposal plants capable of withstanding the presence of toxic substances that accumulate in their bodies.
- Medical Research: Obtaining organs for transplantation from transgenic animals that pose no rejection problems, or use in basic research, such as knockout mice.
Risks of Biotechnology
- Loss of Genetic Diversity: Transgenic plants can invade natural ecosystems and displace native plants, leading to a loss of crop diversity.
- Accidental Gene Transfer: Genes transferred to other wild species or traditional crops could result in herbicide-resistant weeds or pathogenic bacteria that incorporate antibiotic resistance genes used as markers.
- Adverse Health Effects: Allergic problems have been reported due to a lack of information on labels.