by
Rupali
Gupta B.Tech
(food), M.tech (food); Manger-Diets and Nutrition Email: roopali_gupta@yahoo.com
Feb 2003
Genetically
Modified foods-beneficial or harmful?
Before we start the discussion on this burning topic, it is essential to
understand the process of genetic engineering in brief, and it's
application in food industry. Let us discuss from the very basics of
this subject.
What are Genetically Modified (GM) Foods?
Although "biotechnology" and "genetic modification"
are the terms which are commonly used interchangeably. However, Genetic
Modification is the technology that alters the genetic makeup (i.e.
composition of genetic material like DNA and/or RNA) of living organisms
like animals, plants, or bacteria.
Combining genes from different organisms is known as recombinant DNA
technology, and the resulting organism is said to be "genetically
modified," "genetically engineered," or
"transgenic." GM products include medicines and vaccines,
foods and food ingredients, feeds, and fibers.
So, genetically modified foods are the foods that contain some
artificial genetic material along with their natural genetic material.
For example a GM tomato's genetic composition will be different from a
natural (organic) tomato. Moreover, the altered genetic composition of
GM tomato will be transferred to all the tomato-based products.
How genetically modified crops (foods) are developed?
The complete procedure of genetic modification of crops involve a series
of steps. I will try my level best to explain the procedure in simple
language.
Any gene manipulation technique involves following steps
Isolation/synthesis
of desired genes (carrying desired traits), also known as target
genes
Combining these
target genes to a suitable vehicle DNA (also termed as vector DNA)
Amplification of
recombined DNA in the host
Cultivation of gene
in the same host or a different favorable host in which the gene
expresses and synthesizes the product
Harvesting of the
product for commercial use
These steps can be shown in a flow chart as follows:
Target DNA + Vector DNA
Recombinant DNA
TRANSFORMATION
Cells of E. colli containing recombinant DNA
GROWTH
Colony (or clone) of cells carrying the newly introduced DNA
In this manner the desired traits are incorporated in crops, which
eventually give Genetically Modified (GM) foods.
What are the advantages of GM crops (foods)?
Pest resistance-
Crops are susceptible of losses from insect and pests. Farmers
typically use many tons of chemical pesticides annually. These
insecticide sprays have potential health hazards, and run-off of
agricultural wastes from excessive use of pesticides and fertilizers
can poison the water supply and cause harm to the environment.
Growing GM foods such as Bt. corn can help eliminate the application
of chemical pesticides and reduce the over-all cost of crop.
Herbicide tolerance-
Crop plants genetically-engineered to be resistant to one very
powerful herbicide could help prevent environmental damage by
reducing the amount of herbicides needed. For example, Monsanto has
created a strain of soybeans genetically modified to be not affected
by their herbicide product Roundup ®. This practice will eventually
reduces production cost as well as dangers of agricultural waste.
Disease
resistance-There is many viruses, fungi and bacteria that cause
plant diseases. Plant biologists are working to create plants with
genetically engineered resistance to these diseases.
Cold tolerance-Cold
tolerance of various crops can be enhanced by genetic modifications.
An antifreeze gene from cold-water fish has been introduced into
plants such as tobacco and potato. Due to insertion of antifreeze
gene, these plants are able to tolerate cold temperatures that
normally would kill sensitive seedlings.
Improved processing
features- with the help of genetic modification, desired features
can be incorporated in useful crops. For example increasing the
shelf life of tomatoes, increasing the storage-life of other crops
etc.
What are the
disadvantages of GM foods?
Safety
o Potential human health hazards: allergens, transfer of antibiotic
resistance markers etc.
o 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 bio diversity.
Ethics
o Violation of natural organisms' intrinsic values
o Tampering with nature by mixing genes among species
o Objections to consuming animal genes in plants and vice versa
Labeling
o Not mandatory in some countries (e.g., United States)
o Mixing GM crops with non-GM confounds labeling attempts
Cost
o New advances may be skewed to interests of rich countries only
Conclusion
Widespread opposition from the public, farmers and green crusaders has
forced the multinational companies as well as governments to ensure the
adequate labeling in the GM foods. Moreover, some countries are planning
to ban the genetic manipulation of crops at all. Monsanto (a
multinational seed giant) has already withdraw experiments involving
`terminator ‘ gene technology.
This indications show that it is essential to weigh the benefits of GM
foods over natural foods and if possible use this technique only for
limited crops. Some strict quality norms should be set for the companies
and some long-term studies should be done to ensure that GM foods have
no potential harmful effects.
