GM issues | Why fear DNA?
WHY FEAR DNA?
“The World Health Organisation of the United Nations has concluded that there is
no inherent risk in consuming DNA, including that derived from GM crops. This
view is based on the long history of safe consumption of significant quantities
of DNA from a wide variety of sources, including plants, animals and microbes.”
(Report on Project FO1004 prepared for the Food Standards Agency)
Is this conclusion based on sound logic?
Question. What is the history of transgenic DNA?
Does a long history of consuming natural DNA in plants, animals and microbes make it safe to eat DNA which originated in a test-tube, was multiplied in a bacterium, and inserted into an isolated plant cell which was then induced to grow into a whole plant?
None of these procedures has any history of use, safe or otherwise. The reality of genetic engineering is that genes and highly active non-gene sequences of DNA are copied from the genome of all sectors of the living world. They are then heavily altered by man to maximise their function, and attached piecemeal to each other and to some entirely synthetic DNA sequences. These novel constructs have no history of consumption, safe or otherwise.
We now know that when transgenic DNA inserts itself, the plant DNA around it and the construct itself are changed: they gain bits, loose bits and become scrambled. In other words, the DNA in GM food no longer has the sequences occurring in plants, animals and microbes which have a history of safe use. Question. Is it reasonable to conclude that such extraordinary DNA, designed by man and manufactured by man, does not possess any extraordinary properties?
For example …
Transgenic DNA has been specially constructed to form an independent operational
unit which will act outside normal cellular control (even if it kills the cell
by its action), and, will survive intact throughout laboratory manipulations and
the stresses of the field. Can it be assumed that the novel DNA construct will
somehow loose its ability to hang together in an active form once it becomes
food?
We know that operational units of DNA have a long history of transferring between unrelated organisms (horizontal gene transfer). This is not a safe history: E. coli O157 is the recipient of many such transfers.
The regulatory authorities concluded many years ago that operational trans-genes might indeed transfer into microbes inside animals (and you) during digestion. This has, since, been proven to happen.
Concern has so far focused only on the antibiotic-resistance genes often used during the transformation procedure. If these genes transferred into pathogens, the clinical efficacy of related antibiotics would clearly be compromised. But what about other trans-genes?
A bacterium exuding a herbicide-resistance enzyme would probably not be a major health hazard to a human being..
However, a bacterium exuding a ‘ribonuclease’ enzyme, often added to GM crops to aid cross-breeding, raises concerns: this enzyme is designed to dissolve cells in the pollen-producing parts of the flower but could have destructive effects on animal cells (that’s you).
Bt insecticidal toxins are even more problematic. These toxins are added to GM
crops to attack insect gut cells, but are known to have adverse effects in
humans. Huge numbers of different Bt-based toxins are being invented and
inserted into GM crop plants. The genes for these will repeatedly pass through
animal and human digestive systems where bacteria can acquire them. Logically,
bacteria could eventually arise which can exude every Bt toxin ever invented.
A bacterium exuding a drug acquired from GM ‘pharm’ crops could be a medical
nightmare.
In other words, the danger from the transfer of one type of trans-gene has been acknowledged, while much greater potential dangers from other pieces of transgenic DNA moving into bacteria has been, illogically, ignored.
For example …
Transgenic DNA has been deliberately enabled to invade a living genome and to avoid the cell’s natural defenses against foreign DNA. Can it be assumed that the novel DNA construct will somehow loose its infectious potential once the invasion has been accomplished?
We know there is plenty of DNA which is naturally mobile in the genome, and that
its movements are associated with disease processes. We don’t know if transgenic
DNA has the potential to become a mobile element itself. We don’t know how
important DNA mobility is in horizontal gene transfer.
This takes us back to the thorny question of trans-genes hopping into bacteria
in the digestive tract.
For example …
The many components of transgenic DNA have been specially selected to maximise a desired function before being pieced together. Can it be assumed that the individual parts will somehow loose their ability to operate separately once outside the genome?
We know that DNA from food is not completely digested, but can be absorbed and travel around the body: this means that our cells will be exposed to foreign, intact DNA.
The possibility that the trans-genes themselves could insert themselves in the
human genome and generate harmful novel proteins inside us has been dismissed as
far-fetched, because the DNA has been carefully re-designed for insertion and
expression in plants. But, the small, non-gene parts of the novel DNA construct
which promote gene activity are much less species-specific and are much less
gene-specific. These would wreak havoc within a human genome just by their
presence.
This raises the question, are the possibilities of cancer, autoimmune reactions or tissue disease arising from such genome interference so far-fetched? Our immune system has evolved to ward off viruses as ‘enemy’, to recognise food as being food, to recognise our own DNA as being ‘self’, and to react or not react accordingly . But, pieces of active viral DNA could be disguised by their attachment to unrecognisable synthetic DNA, or, worse disguised by their attachment to human-derived DNA. These could enter our cells unnoticed, or, could stimulate a catastrophic immune system reaction by their invasion of the genome.