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Genetically modified crops - February issue

Neil McRoberts n.mcroberts at au.sac.ac.uk
Mon Feb 15 05:18:02 EST 1999

On Sat. 13 Feb Ben David wrote:
> Phil Jones wrote:
> > It is being put about by the media that genes from GM foods could
> > enter the human gene pool via the stomach, and so cause human
> > gene modification.
> > If true then all animals have been sharing genes with other animals and
> > plants for millions of years.
> > So whats so bad about that?.
> > The fuss about the GM potatoes encourages me to ask the question:
> > were non-GM potatoes run as a control?
> > If we start treating foods like drugs then think of all the results
> > that would come from the testing of everyday foods. I can't believe
> > that no common food has potential risks to the immune system
> > or general health.
> Yes but:
> 1) No common food has had its genes tampered with in this invasive way.

This depends on what you call "invasive".  In breeding Triticale one 
crosses wheat and rye to produce a polyploid novel genome.  Having 
suddenly to share ones cells with another complete set of genes could be 
thought of as having been a little invaded.  There don't seem to be many 
calls for triticale to be removed from world agriculture.

> The fact is that organisms have NOT been "sharing genes" like this. Not
> for millions of years, not ever.

I'm not sure that you're righ about this.  Certainly until relatively 
recently there weren't any human agents that brought about such transfers 
of genes, but there's lots of evidence that it happens naturally.  A 
common and troublesome example for gardeners is the ability of 
Agrobacterium tumefaciens to insert several genes on a plasmid that it 
carries into the genome of its plants hosts and thus to induce the 
symptoms we recognize as crown gall.  It does this quite well in 
test-tubes, but it was out there doing it in the soil a long time before 
people knew anything about it.  There are other examples too of course.  
The mitochondria that allow the respiration required to let you live, and 
the choloroplasts that allow green plants to use the energy in light to 
fix carbon were probably free-living organisms once upon a time - their 
entire genomes have become integrated into more complex organisms.

> And it's highly likely that grafting a
> snippet of fish DNA into the completely different environment of a
> carrot may cause more unforeseen problems than the natural genetic
> mutations that occur within a population of carrots.

Is it really?  What evidence do you have for this assertion?   What makes 
you think that natural mutations in a carrot genome (already fairly 
heavily altered from its wild state by selective breeding by the way) 
would be any less dangerous?

> 2) Someone is charging money for this. Someone is selling this. That
> someone has to give assurance of safety.

Just as someone makes money from selling all of the "traditional" 
agricultural products.  That certain companies will make money out of the 
technology  is not a sufficient argument in itself, surely, to demand that 
the technology is not used.  There may well be other arguments against it, 
of course.

> Hey, if I had such a wonderful
> product - I'd make the growers put a fancy sticker on every tomato. Yet
> the Monsantos of the world are doing all they can to keep their produce
> from being labelled, to keep the decision out of the consumers hands.

Labelling of GM foods as GM would be a great idea.  That way we 
(consumers) could make up our own minds about buying them or not.  If it 
turns out that we don't actually mind the risks (and there might well be 
risks associated with this technology) then we'll buy them and they'll 
become part of everyday life.  If the companies who produce them have got 
it wrong, and our fears are too strong to be overcome, we won't buy them 
and they will cease to be an issue.

> Why? The agritech companies have learned their lessons. It's now thirty
> years since thalidomide, and forty-odd since DDT was rolled out.  The
> agritech lawyers are doing all they can to cover their tracks, to make
> sure that any negative effects cannot be traced back to their products.
> What will the consumer say? "My child developed the symptoms after
> eating a tomato". Right, madam.......which tomato? Once the regulatory
> battles are won, once the GM produce hits the markets, there will be no
> trail of accountability.

I think you are making a mistake in trying to link GM foods to recent
examples of failures in technological development on the basis that bad
old big business is simply out to make money with heed of the
consequences.  As a society we consent (or not) to the application of
scientific discoveries in our lives.  The level of intervention that we
have in the process of discovery and application is also something that we
decide upon.  Most of the time most of us aren't interested/don't
care/aren't well informed enough/etc to get involved.  Sometimes it goes
badly wrong (thalidomide for example) and we ask ourselves why things were
allowed to get so far without someone asking whether this was a good idea.
 Sometimes as a result of this questioning things are dome differently. 
For GM crops/foods the debate is taking place right now.  Surely the
important thing is that the debate should be a rational one and based on
the current state of knowledge?

Best wishes
Dr Neil McRoberts
Plant Biology Department
Plant Science Division
SAC Auchincruive
Ayr, KA6 5HW
tel +1292 525304
fax +1292 525314

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