NANFA-- Genetically Modified Corn and its effect on the environment.

Sajjad Lateef (
Fri, 6 Sep 2002 13:00:21 -0700 (PDT)

A bit off-topic (but does mention water resources).

I wrote up a short essay on Genetically Modified Corn and its
effects on the environment for a discussion with some
colleagues. I thought I would share it (slightly modified)
with the NANFA list.

Please delete if the subject does not interest you.

Comments are welcome.

Genetically Modified Corn and its effect on the environment.

1. Genetic Modification in plants.

GM is the modification of genes in plants to bring about
changes. This can be done by either identifying genes from
same species or by identifying genes from other organisms
(like Bacteria) and introducing these genes into the
plants. In the first instance, it is done by selective
breeding. In the second instance, it is done by molecular
biology techniques. These types of plants are called
transgenic plants.

Several scientists work extensivly on Host Plant Resistance
where they identify wild relatives of food crops which are
naturally resistant to insects and selectively bred this
resistance into commerical varieties. This is an example
of the first instance. In this case, the resistance is
something that the plants developed themselves in nature over
thousands of years. Scientists identify the resistant plants,
selectively inter-breed them with common varieties, test and
retest and finally release these now naturally-resistant
varieties to farmers. This is the kind of work being done
by institutes like ICRISAT ( )
in India and CIMMYT ( in Mexico etc.

BT-maize is an example of the second instance where a gene
is extracted from a Bacteria (Bacillus thuringiensis aka BT)
which produces the toxin Bt Delta Endotoxin (which is deadly
to larvae of stem borers). This gene was extracted from
the bacteria and introduced into maize varieties which are
then grown and marketed as BT-corn. Now, the plant itself
produces the Endotoxin and kills any larvae that attack it.

see: "Bt-Corn: What it is and How it works"

2. Impact of GM-corn

The major scientific concern of GM-Corn or BT-corn (i.e. the
non-political, non-social, non-economic concern) is that a
non-natural gene has been introduced into a widely utilized
food crop. Since Maize/Corn readily inter-breeds with other
corn varieties, the BT-Corn gene can be readily introduced
into a native population by cross-pollination. This threatens
the natural diversity of the wild crops. Due to both natural
and human factors, the transgenic plants will spread their
genes to wild plants and will slowly reduce the diversity
of the wild population.

While scientists are just not sure yet of the long term
impacts of the introduction of BT-corn genes into wild
population, they DO KNOW that a reduction in the diversity of
the wild poplulation will have potentially disastrous effects
Inbreeding eventually causes problems which are usually
offset by introducing other genes from the wild population.
But, if there is no wild population left without BT-corn
genes, then there is no wild genes left to save the crop
from the effects of inbreeding or a new disease. Eventually,
the entire crop in-breeds itself to extinction. Since so much
of the world depends on corn for food, no more corn means big
trouble for the world.

See: "Mexican study raises GM concern"


btw, CIMMYT is the leading research institute in the world
on Maize/Corn and is a research center of CGIAR (Consultive
Group on Intl Agricultural Research) - supported by UN's FAO.

There are also concerns that the BT-corn may even release
the Endotoxin into the soil where it remains without breaking
down. This has the possibility of contaminating groundwater
and surface water (possiblity affecting aquatic life and
the food chain that depends on water-bodies).

3. Effects of gene flow from transgenic crops to wild relatives.

Gene flow from transgenic crops to wild relatives is enough
of a concern that the USDA sponsors research on this topic.
Scientists do not really know the effects of gene flow but
what little they do know worries them.

USDA's Biotechnology Risk Assessment Research Grants Program
( )
sponsored a workshop on "Ecological and Agronomic Consequences
of Gene Flow from Transgenic Crops to Wild Relatives"

4. Why would you worry about such a thing like gene flow?

Well, just for grins, take a look at this:
"Scientists Create GM Corn Which Prevents Human Conception"
"GM corn set to stop man spreading his seed ",6903,548964,00.html

This is an extreme case. But, just imagine the consequences
of eating some *special* 'corn on the cob' at a summer picnic.
I am sure that there is no sane person on this world who would
contemplate releasing such corn to other people. But, there are
enough nutty people around that I am concerned.

As a environment conservationist, and a concerned citizen of
this Earth, the long-term consequences of transgenic mutation
by Genetically Modified plants on food crops scares me. A LOT!

Sajjad Lateef


Sajjad Lateef
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