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This is the final part in answer to your "rebuttal". I want this time to be more upfront.
At the beginning you said you had constructed a list of scientists who had signed a petition against GM.
Unless that list contains virtually all plant scientists then frankly in my opinion it is useless. Detailed
examinations by psychologists have shown that outside their narrow area of expertise, scientists are not
better informed than the average well-informed layman and just as prone to silly mistakes. Simply calling
someone a scientist can be used to try and imply to the public that this individual has detailed knowledge
whereas the reality is that he is no better informed than anyone else. Within an area of expertise built up by
experience, reading, research and publishing journals a totally different perspective is created so that the
thinking becomes different. That is what psychologists tell us. I can certainly give examples where
Greenpeace 'scientists' have made incorrect statements about genetic 'pollution' which simply indicate lack
of knowledge and experience. In fact so far as I am concerned the expertise in this area is confined to long
serving plant scientists and they will not form anything but a very small minority of plant scientists on your
list. Physicists, chemists, mathematicians and medics have no better knowledge about plant biology,
breeding than any other lay person. They can be frightened by simple statements and slogans which
through lack of background they are unable to critically examine. I was in contact ages ago with a
gardeners against GMO group who believed that GM maize was going to cross pollinate with flowers in
their garden! They actually sent a petition to 10 Downing Street and there were on the list a number of
individuals who run garden nurseries.
Prakash has a list of several thousand and I believe that most of these are plant biologists and plant
breeders. In the article I wrote for Nature I made the point that opponents against GM for crops came from
outside the plant community. Now why is this the case. Am I simply trying to defend a career? No. I think
we need GM for the future of man and I cannot see why there is such a fuss made. OK we can move
genes from other organisms...what's new. We have been shuffling genes from weeds to crops for some
time...we have been bombarding plants with X rays, and radioactivity to generate mutants and many of
these crops are currently available and used extensively. When you put new genes by crossing with
weeds or mutagenise, a lot of testing goes on so that you get what you want. In fact an enormous amount
of selection is gone into; you don't just use the first thing that comes along. And when you have selected
you then go into examination of behaviour under field conditions.
When I reject what you say it is simply that long experience has taught me a different perception of what to
be concerned about and persuade me that there is nothing wrong with GM. There are regulations, I regard
most of them as excessive and have said so. But like most in the area I have had to go back into my reading
and thinking as to why I do not have the concerns that others outside the area do. In my view it is
commonly because their preconceptions about what has been done in the past is hazy in the extreme, little
is known by most people of even simple plant biology and there is a general but unjustified fear concerning
the word genes and the subject matter genetics. Others have a general feeling that nature is nice and
pleasant and one shouldn't interfere with it despite the fact that their daily food comes from such
interference. But the experience I have cannot be acquired in short order. I have been in the business for 40
years! I have a much more detailed knowledge and understanding of my area of expertise than most I know.
That doesn't make me arrogant it merely makes me knowledgeable just as Eva is knowledgeable about
astrophysics and I am not. But at some stage recognition is required that scientist is not a very meaningful
term and only those with detailed insight are likely to be able to give a more balanced assessment.
Most crucial to me is the actual experience of carrying out the technology. You can read what is done for
transformation but it isn't the same as actually doing it because many important things get left out of
schedules. So with experience you become aware of the variation in expression between different
individuals, of the instability of some lines and the necessity of generating large numbers so that selection
of an optimal line can be achieved. The more you do the greater the clarification and the difficulties emerge.
Along with that is the simple difficulty of actually getting bits of DNA to be incorporated into plasmids so
they can be expressed in bacteria; this can sometimes take 6 months or a year of continuous work. So the
perception that the process will happen with any old bit of DNA is simply wrong.
The other thing that strikes me again and what I had hoped you would get out of the Aachen declaration is
that if Nature has here been doing everything for hundreds of millions of years why the sudden concern?
So an endosymbiont in a bees guts has been taking up DNA. It's been doing so for many millions of years
and bees have harvested pollen from every part of the planet; trillions of different genes. The
endosymbiont is still an endosymbiont it hasn't gone green or grown flowers to be silly. Bees are still bees.
If horizontal gene transfer was common between plants and bacteria look for nitrogen fixation genes in
plants because they should be there; but they are not. Rhizobium and legumes have lived intimately for 50
million years. When I hear statements about transferring antibiotic resistance by such a route through
endosymbionts, I cannot take it seriously. The main repository of antibiotic resistance is commensal
bacteria in cattle. In that case unpasteurised cheese and manure are the high risk routes. Anything from
GM is so marginal it can be ignored. The bee endosymbiont is clearly fragments of DNA. Fragments of
DNA have turned up in milk and in blood cells. What's new. It has been happening since our ancestors
started eating grass.
Finally population predictions. The nearer the time the more accurate can be the prediction. Predictions in
1950 for the US population were wrong by about three fold for the year 2000 and all were underestimates!
So when I say 8.3 billion for 2025 well it could be nine billion, it could at a pinch be seven billion, better to
overestiamte the problem and at least that might leave excees food than underestimate i9t and run into
serious problems. However 8.3 billion is based on the children presently here on this planet and
assumptions about how many children they will have. Like everything for all of us, the future is simply
unpredictable. As regards economics; Julian Simon bet Paul Ehrlich in 1980 that every natural resource
would be cheaper by 1990. Simon won his bet. Ehrlich (a biologist) had been saying that with resources
running out the price would rise. Simon is/was an economist and knew that naive ideas that relate resource
limitation to price often don't do well over the longer term.
I hope all of this has been of some benefit so that you can see the way I think about GM even if you don't
agree. But then scientists disagreeing with each other...what's new.
Anthony Trewavas FRS
Institute of Cell and Molecular Biology
University of Edinburgh
Edinburgh EH9 3JH
Phone 44 (0)1316505328
Fax 44 (0)1316505392
web site http://www.ed.ac.uk/~gidi/main.html
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