labelling....

The U.S. Food and Drug Administration (FDA) has ruled that the new genetically modified strains of food do not need special labeling (thus many are unknowingly eating genetically modified foods). The FDA currently requires no labeling because it believes that genetically modified foods are not significantly different than hybrids developed by cross breeding.

Genetically modified foods are different, however, from hybrids. Whereas many hybrids are the results of crossing two or more varieties of the same species, genetically modified foods do not need to be. Actually, it is believed to be possible to insert the gene of an animal (or a different species of plant) into a plant in order to make a genetically modified plant, such cannot occur with normal hybrids: "Potatoes may be spliced with chicken genes, tomatoes spliced with fish genes, corn spliced with 'virus' genes, pigs spliced with human genes. Bacteria, insect, and animal combinations and various plant combinations produced. Manufacturers can sell bioengineered foods without [adequate] safety testing or disclosure.

Controversies

Controversies

Safety
-Potential human health impact: allergens, transfer of antibiotic resistance markers, unknown effects
-Potential environmental impact: unintended transfer of transgenes through cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss of flora and fauna biodiversity

Access and Intellectual Property
-Domination of world food production by a few companies
Increasing dependence on Industralized nations by developing countries
Biopiracy—foreign exploitation of natural resources

Ethics
-Violation of natural organisms' intrinsic values
Tampering with nature by mixing genes among species
Objections to consuming animal genes in plants and vice versa
Stress for animal

Labeling
-Not mandatory in some countries (e.g., United States)
Mixing GM crops with non-GM confounds labeling attempts

Society
-New advances may be skewed to interests of rich countries

http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml

GM food benefits???

Benefits
Crops
-Enhanced taste and quality
-Reduced maturation time
-Increased nutrients, yields, and stress tolerance
-Improved resistance to disease, pests, and herbicides
-New products and growing techniques

Animals
-Increased resistance, productivity, hardiness, and feed efficiency
-Better yields of meat, eggs, and milk
-Improved animal health and diagnostic methods

Environment
"-Friendly" bioherbicides and bioinsecticides
-Conservation of soil, water, and energy
-Bioprocessing for forestry products
-Better natural waste management
-More efficient processing

Society
-Increased food security for growing populations

http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml

PCR

The analytical methods contain the following steps:
1.- Extraction of DNA:
It is necessary to extract the genetic material free from other impurities which might interfere in further steps of the analysis.

2.-PCR reaction ( Polymerase Chain Reaction)
The PCR reactions are suited to multiply and amplify specific fragments of DNA that are alien genes to the food being analysed.

The primer starter molecules used in the beginning of the reaction decides which sequence of DNA will be multiplied.

To avoid false negative results due to inhibit action of impurities during extraction of the DNA it is important to include a positive reaction.

3.-Making the PCR product visible Through gelelectrophoresis (agarosegelelectrophoresis).

The products of the PCR reaction can be made visible together with the determination of the length of the base pair, the alien gen.

4.-Confirmation of the results

The confirmation of the results are being made by controlling the sequence of the base in the PCR product using specific sequence restriction, hybridization with specific sonde Nested PCR and Sequencing The basic PCR gives only qualitative indications.

To obtain quantitative results the Competitive PCR or the RT-PCR should be used

Dna detection method

Western Blot

The method of Western Blot the extraction of the transgenetic protein from the food is done by means of a nitro-cellulose membrane which binds the proteins. The membrane is immersed in a solution of a specific antibody together with an enzyme resulting in a colour reaction. This method is very labour intensive and therefore not being used in routine.