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July 19, 2000


Animal Feed, Precautions, Transposons


AgBioView - http://www.agbioworld.org, http://agbioview.listbot.com

Subj: Re: Animal feed
Date: Wed, 19 Jul 2000 9:12:03 PM Eastern Daylight Time
From: Ray and June Shillito
Date: Jul 19 2000 02:11:10 EDT
From: "Hugh Edwards" Subject: GM food and animal testing query

In a recent edition of an Australian newspaper 'The Weekly Times', a
letter was printed which cited US and Canadian research findings that
animals had refused to eat GM foods to the point of starvation.

As someone who has met with representatives of the feed and animal
industry, and has carried out feeding studies with biotech corn, rice and
soy, I can state that we have never heard of such a report, and I believe
that it is an outright lie.

Ray Shillito
Aventis CropScience

Date: Jul 19 2000 19:42:02 EDT
From: Malcolm Livingstone Subject: Re: precautions

Dear Thomas,

I guess that we agree generally but I still think the Precautionary
Principle should be no more than the application of commonsense. Really
there would be few who would disagree that we need to apply caution to new
technologies. However this principle has been hijacked by some extremists.
Scepticism of authority exists in society. However most people, most of
the time, don't mind delegating responsibility to "authority". After all
there is no workable alternative. As far as who is qualified to judge
safety in scientific matters there is no credible alternative to using
scientists. I don't share your belief that society doesn't trust
scientists involved in this debate. In the US it seems most people still
trust scientists and it is just as well they do otherwise disasters are
likely to occur. It may be that it is not good to let Monsanto scientists
test the safety of GM crops. I am sure they are honest people with plenty
of integrity but I guess the public would happier if there was an
independent arbitrator.

In any case the idea of a Precautionary Principle is fine if it is not
abused. My point is that I fear some NGO's are misusing it. It is clear
that some don't want GM crops whatever testing is done and this is
unreasonable or at least ideologically driven. All technology is tested
for safety, some more than others. I don't see biotechnology as some
quantum leap into the unknown. Somebody has to make the assessment sooner
or later
and I can't see who is qualified to do so unless it is scientists. Not
just any scientists but those who represent the majority view in science.
In fact that is precisely what has happened with the 7 academies of
science statement. If you can't trust these people then give up trusting
anyone, turn on the X-files, lock the door and load your gun.

Malcolm Livingstone

At 08:44 19/07/00 -0400, you wrote:
What underlies the Precautionary Principle is the idea that nothing is ever
100% safe. OK so far. However it also states that nothing can be done
unless 100% safe (at least according to many anti-GM activists).

Date: Jul 19 2000 20:58:25 EDT
From: Malcolm Livingstone Subject: transposons

Dear All,

I have several times written about the natural occurence of transposons
and retroviruses and their relevance to the safety of genetically
engineered plants. Here is a little more information.

Transposons are ubiquitous in plants as far as I know. They come as two
basic types; those that code for their own transposase (enzyme that cuts
out the transposon and reinserts it randomly in the genome; eg Ac in
maize) and those that have lost their own transposase but are activated by
transposase produced by other transposons (eg ds in maize). The number of
these elements found in the genome is truly staggering. Tobacco has about
200000 Ts elements per genome and maize well into the 100000's. they can be
active in germline cells or somatic cells. They are often induced by
stress. Stress for these elements can be as simple as living in a field.

A good example of these in action is the new roses available in nurseries
which have coloured sectors on their leaves. This effect is due to
transposon activation and insertion into anthocyanin genes in individual
somatic cells. There are several of these genes each one responsible for a
particular colour. For example one might be responsible for blue another
for red and yet another for yellow. Some species have all of these genes
and come in a wide variety of colours others lack some and therefore the
colour range is restricted (for example roses lack the gene for making
blue pigment and therefore it is impossible to breed for a blue rose). In
fact this is the basis of a long standing project run by Calgene who want
to insert the blue gene into roses. They have already succeeded with
carnations. By the way it is known that some transposons are the remains
of tRNA's that have become integrated into the genome (I think the Ac
element is a tRNA for isoleucine but I'm not sure).

In addition to transposons there also exist retroviral footprints. These
litter the genomes of many plants and animals (including our own). A
recent review in TIG covers this nicely (Peterson-Burch et. al.,TIG
vol.16, 2000). They show that there are about 40 retroelements found to
date in plants. One element alone (the Athila element) constitutes some
0.3% of the Arabidopsis genome. They have ORF's that often code for
envelope proteins etc. and are probably viral in origin.

When we transfer genes randomly into a genome we are doing nothing
different than what occurs naturally except we are only transferring one
gene instead of hundreds of thousands. Perhaps you can now begin to see
why most plant molecular biologists do not fear GM crops. Nature is way
ahead of us.

I would like to thank Dr. Stephen Mudge of CSIRO Tropical Agriculture for
his expert advice on this subject.

Malcolm Livingstone

Northern Grains Improvement Ph: (07) 3214 2___
CSIRO Tropical Agriculture Fax: (07) 3214 2288
306 Carmody Rd Int.Ph: +61 7 3214 2___
ST LUCIA QLD 4067 Int. Fax: +61 7 3214 2288