GMO Myths and Truths

1. THE GENETIC ENGINEERING TECHNIQUE
1.1 Myth: Genetic engineering
is just an extension of natural
breeding
Truth: Genetic engineering
is different from natural
breeding and poses special
risks
GM proponents claim that genetic engineering is
just an extension of natural plant breeding. They
say that GM crops are no different from naturally
bred crops, apart from the inserted foreign GM
gene (transgene) and its protein product. But this
is misleading. GM is completely different from
natural breeding and poses different risks.
Natural breeding can only take place between
closely related forms of life (e.g. cats with cats,
not cats with dogs; wheat with wheat, not
wheat with tomatoes or fish). In this way, the
genes that carry information for all parts of the
organism are passed down the generations in an
orderly way.
In contrast, GM is a laboratory-based technique
that is completely different from natural breeding.
The main stages of the genetic modification
process are as follows:
1. In a process known as tissue culture or cell
culture, tissue from the plant that is to be
genetically modified is placed in culture.
2. Millions of the tissue cultured plant cells are
subjected to the GM gene insertion process.
This results in the GM gene(s) being inserted
into the DNA of a few of the plant cells in
tissue culture. The inserted DNA is intended
to re-programme the cells’ genetic blueprint,
conferring completely new properties on the
cell. This process is carried out either by using a
device known as a gene gun, which shoots the
GM gene into the plant cells, or by linking the
GM gene to a special piece of DNA present in
the soil bacterium, Agrobacterium tumefaciens.
Section at a glance
u Genetic engineering is completely different
from natural breeding and entails different
risks. The genetic engineering and associated
tissue culture processes are imprecise and
highly mutagenic, leading to unpredictable
changes in the DNA, proteins, and
biochemical composition of the resulting
GM crop that can lead to unexpected
toxic or allergenic effects and nutritional
disturbances.
u Foods produced by cisgenic or intragenic
methods are as hazardous as any other GM
crop.
u It is misleading to compare GM with
radiation-induced mutation breeding and
to conclude that, as crops bred by the
latter method are not tested for safety or
regulated, neither should GM crops be tested
or regulated. Radiation-induced mutation
breeding is potentially even more mutagenic
than GM, and at least as destructive to
gene expression, and crops produced by
this method should be regulated at least as
strictly as GM crops.
u It is unnecessary to take risks with GM
when conventional breeding – assisted by
safe modern gene mapping technologies – is
capable of meeting our crop breeding needs.
When the A. tumefaciens infects a plant, the
GM gene is carried into the cells and can insert
into the plant cell’s DNA.
3. At this point in the process, the genetic
engineers have a tissue culture consisting of
hundreds of thousands to millions of plant
cells. Some have picked up the GM gene(s),
while others have not. The next step is to
treat the culture with chemicals to eliminate
all except those cells that have successfully
incorporated the GM gene into their own DNA.
4. Finally, the few cells that survive the chemical
treatment are treated with plant hormones. The
GMO Myths and Truths 9