Ontario Agri-Food Technologies – Issues Analysis

Issues Analysis
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Issues Analysis

Science Reporting and Public Perception

GMO potatoes:

In the fall of 1998 and spring, 1999, the media in the United Kingdom
erupted with claims that “genetically modified potatoes” adversely
affected rats in terms of both growth and immune function.

Dr. Arpad Pusztai of the Rowett Institute in the U.K conducted the
experiments that caused this widespread public fear of genetically
modified food. The experiments involved feeding rats potatoes either
genetically modified to express lectin, a gene found naturally in the
snowdrop plant, or potatoes with lectin added but not genetically
modified. Lectin is produced naturally by some plants to protect
themselves from insects.

We stress that these potatoes were not in the food system and they
would never be sold as food if there were adverse effects to mammals.

In response to the public concerns and because Dr. Pusztai’s work had
not been peer reviewed, the Royal Society of England convened an
independent review of the study. The results released May 1999 were as

  • On the basis of the information available, it appears that the
    reported work from the Rowett Research Institute was flawed in many
    aspects of design, execution and analysis and that no conclusions should
    be drawn from it.
  • No convincing evidence of adverse effects from GM potatoes was found
    upon review. Where the data seemed to show slight differences between
    rats fed predominantly on GM and on non-GM potatoes, the differences
    were not interpretable because of the technical limitations of the
    experiments and the incorrect use of statistical tests.
  • The work concerned one particular species of animal, fed with one
    particular product modified by the insertion of one particular gene by
    one particular method. However skillfully the experiments were done, it
    would be unjustifiable to draw from them general conclusions about
    whether genetically modified foods are harmful to human beings or not.
    Each GM food must be assessed individually.
  • The whole episode underlines how important it is for research
    scientists to expose new research results to others able to offer
    informed criticism before releasing those results into the public arena.

The bottom line is that widespread fear was created in consumers
by flawed, non-peer-reviewed science, that would not have been accepted
for publication. The media entered the feeding-frenzy without waiting for
independent evaluation.


  • The Royal Society is an independent academy promoting the natural
    and applied sciences. Founded in 1660, the Society has dual roles; as
    the UK academy of science, acting nationally or internationally, and as
    the provider of a broad range of services for the scientific community,
    including fellowships and grants.

The Monarch Butterfly:

In May 1999, John Losey and others from Cornell University published an
article in Nature entitled “Transgenic pollen harms Monarch larvae”. I
emphasize that the article was peer reviewed and as such meets one of the
first tests of reputable results. The concern is how the media is
interpreting the results to suggest that transgenic pollen from corn is
causing the elimination of Monarchs which some have described as the
“Bambi of the Insect World”.

First the experiment was a laboratory study designed to determine if
toxicity existed. Leaves lightly misted with water were treated with
pollen that visually matched milkweed leaves from cornfields. The
caterpillars tested were 3-days old, which is very young, and one would
expect maximum toxicity in young larvae.

This experiment indicates that there is “potential risk” to Monarchs
and field studies are required. E.g. how likely is it for Monarchs to feed
on milkweed within a cornfield? How often is the pollen likely to stick to
the leaves? How far would sufficient pollen move to cause toxicity outside
a cornfield?

Importantly, how much of a risk is this compared to:

  1. herbicide treatments used to control this noxious weed
  2. destruction of overwintering grounds in Mexico
  3. mortality of adult Monarchs by automobiles

The laboratory
study requires follow-up with field research to ascertain the risk in
nature. Until then, media should refrain from reporting the demise of the
Monarch from genetically modified corn.

Written by Dr. Gord Surgeoner
President, Ontario Agri-Food
& Faculty Member, University of Guelph
May 1999


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