Open access to science eprints
TheSparc provides both scientists and the general public free open access to scientific papers that are important for the survival of people and planet
ISIS Report 13/03/04
Exposed: More Shoddy Science in GM Maize Approval
Dr. Mae-Wan Ho The Food
Standards Agency appears to be selectively promoting and suppressing research
results in projects it funds
Scientists should be afraid, very afraid of the extent to which the
academic-industrial-military complex is bending science to suit its purpose.
No, I am not only speaking about the United States, but the United Kingdom
Horizontal gene transfer a major uncertainty in GM safety
In the current issue of Science in Parliament , I found no
less than three mentions of horizontal gene transfer as a major uncertainty in
the safety of GM crops: in an article by Michael Meacher MP, "GM: the politics
of uncertainty", in a Parliamentary debate on biotechnology by Joan Ruddock,
and in the article " Nanotechnology: friend or foe?" by Prof. George Smith of
Horizontal gene transfer is the process whereby genetic material jumps
into foreign genomes, or put the other way round, whereby foreign genetic
material jumps into genomes. That is exactly what genetic modification
involves: artificially constructed DNA (called GM DNA or transgenic DNA)
cobbled together from a wide variety of sources or simply made in the
laboratory, is inserted into the genomes plants, animals and livestock.
But horizontal gene transfer can also happen unintentionally and without
our knowledge. It is the main process creating new viruses and bacteria that
cause disease epidemics and spreads antibiotic and drug resistance besides,
making the diseases more difficult to treat. Foreign genes jumping into
genomes, as many investigations on the genetic modification process itself
reveal, causes extensive genetic damage, scrambling and rearranging genomes,
resulting in inappropriate gene expression that can trigger cancer.
Theres lots of evidence that transgenic DNA may be more unstable
and more mobile than natural DNA , and molecular analyses of commercially
approved GM crops, carried out belatedly last year, found that practically all
the inserts have rearranged since characterised by the company [3,4].
One big question is: what happens to the transgenic DNA thats in
GM food and feed? I have raised this question on numerous occasions with our
government over the past ten years, one of the more recent occasions during the
public hearing on Chardon LL T25 transgenic maize organised by the Advisory
Committee on Releases to the Environment (ACRE) in 2002 .
At the same hearing, it was revealed that twice as many broiler chickens
died eating GM maize as non-GM maize. But because the experimental design was
so flawed, statistical analysis failed to detect a significant difference
between the two groups. Prof. Orskov of the Macaulay Institute raised the issue
of whether milk from dairy cows was safe to drink, and spokespersons from
Friends of the Earth also pressed for feeding tests in the appropriate species
cattle - instead of rats and broiler chickens.
ACREs written response to the Chardon LL Hearing (December 2002)
stated : "The Company - Bayer - has commissioned a dairy cattle feeding
study with T25 maize and will present the data to the French competent
authorities when completed. As is the standard practice, ACRE will review new
information generated in this trial and update the risk assessment
Mystery of the missing study
But the result of this study has yet to see the light even though the GM
maize has now been approved for commercial growing as cattle feed.
Dr. Brian John of GM-Free Cymru wrote to ACRE 24 February expressing his
concern that there are no published or peer-reviewed ruminant feeding studies
on the effects of T25 maize  and asked to see the study mentioned by ACRE,
especially in view of the recent report that twelve dairy cows in Hesse Germany
died after eating Syngentas GM maize 176 . ACRE has not replied,
despite a reminder sent 5 March.
The study was supposed to have been done by Professor Richard Phipps in
the Centre for Dairy Research (CEDAR) at Reading University.
"There is no mention of the study on the CEDAR website." Brian John
said, "If the Chardon LL used in the study came from the FSE trial sites, that
would have contravened the FSE rules, and a separate consent must have been
signed by somebody."
Bayer was reportedly given a report of the study late in 2002, and one
of the researchers involved, David Beever, claimed the report had gone to
On 9 March, Brian John finally received, via the Welsh Assembly, a
"Background Information" paper from Richard Phipps, stating that the study
was conducted at the University of Reading for Bayer Crop Science. The
objective of the study was to determine the effect of silage derived from T25
maize on feed intake and milk production in lactating dairy cows compared with
a near isogenic counterpart and silage of two further commercial maize
Furthermore, it stated that the study has been completed and presented
to the company, and they are in the process of preparing their data for
publication in an international scientific journal once the peer review process
has been completed, the same process followed in the study they conducted for
the UK Food Standards Agency, published in the Journal of Dairy Science
, a copy of which was enclosed.
They then went on to state,
"While it is not our policy to release details of studies prior to peer
review we feel able to say that the compositional, fermentation characteristics
and nutritional values of all four silages were comparable and that there were
no significant differences in milk yield, milk composition and yield of milk
constituents, when comparing the four rations. In addition GM DNA was not
detected in any of the milk samples analysed by Polymerase Chain Reaction
methodology. Cows remained in good health throughout the study period."
Notice that the study focussed on silage, not on maize grain, which is
also widely fed to cattle. It concentrated on detecting GM DNA in milk, but not
the mouth, rumen or intestinal contents, blood, meat or other animal tissues,
where positive results have already been reported (see below).
The FSA-sponsored study is presumably the reason our government has
given the go-ahead for approving Chardon LL T25 maize to be grown for cattle
feed, as the T25 study has yet to be published and there is a dearth of
published studies on feeding ruminants with GM feed. So, how does that study
stand up to scrutiny?
Study that found no results worth reporting is worthless
The study failed to find significant survival of GM DNA, or indeed any
single copy DNA in most of the tissue and tissue contents examined; but it is
First of all, the FSA-sponsored study has nothing to do with Chardon LL
maize. It was work carried out with a mixture of both Monsantos
Roundup Ready soya GTS 40-3-2 (as soya meal) and Mon 810 maize (as maize grain)
at the same time, comprising only 13% and 18.5% respectively of the total diet.
This inevitably decreases the chance of detecting the GM DNA belonging to the
Second, only six cows were used, three fed the GM diet and the other
non-GM. But a peculiar "single reversal design with three 4-wk periods" was
used, which I believe, meant that the groups of three cows alternated between
GM and non-GM diets. Thus one group would spend the first four weeks on GM, the
next four weeks on non-GM and then four weeks back on GM; while the feeding
regime for the other group would be non-GM, GM, and non-GM. This design
generates in effect 9 data points each for the GM diet and non-GM diet. But, it
also guarantees to balance out the effects of GM versus non-GM diet and hence
is utterly worthless as far as detecting difference in weight gain or any other
developmental or physiological indicators between the diets.
Third, the researchers made a big blunder. Two of the cows in the non-GM
group were inadvertently fed on the GM-diet, so they ended up with 13 data
points in the GM diet group and only 5 data points in the control non-GM diet
Fourth, even though they had taken apparently carefully timed samples
from individual animals in each four week period, they pooled all the
samples from the same animal together, thus losing potentially valuable
information regarding the time course of the clearing of GM DNA from the gut to
the tissues and out of the body.
Fifth, and most serious of all, their PCR method for detecting GM DNA is
neither validated nor standardized. Its sensitivity varied over 1000 fold
between different tissues and tissue-contents. The limits of detection is such
that in some samples, I calculate that more than 4 000 copies of the soya
genome or 900 copies of the maize genome must be present in the sample before a
positive result is obtained. The usual detection limit of PCR is 10 copies or
less. Thus, given the minute amounts of tissues and tissue contents used in a
PCR test, as for example, 0.3 millilitres of milk, it is no wonder that the
only DNA that can be detected at all reliably is the chloroplast gene, which
exists in 10 000 copies per plant cell. And no wonder there is a rather large
number of neither positives nor negatives, but "inconclusives" in the data.
Poor PCR amplification is one of the most common causes of failing to
detect GM DNA
The "Background Information" on the study on Chardon LL claims that
their as yet unpublished results "support the 30 other peer-reviewed papers in
international scientific journals, which have failed to detect GM DNA in milk,
meat and eggs derived from animals fed diets containing GM feeds."
In fact, poor PCR amplification is probably one of the most common
causes of having "failed to detect GM DNA". A Japanese research team, which has
documented the survival of both GM DNA and Bt toxin protein in the digestive
tract of mice, pigs and cattle , nevertheless reported a failure to detect
GM DNA in blood because as they stated, the PCR did not work in blood. There
are many unknown PCR inhibitors in different tissues that can give false
negatives. Phipps and coworkers also failed to detect single-copy DNA in blood,
GM or otherwise, they failed to detect even the abundant chloroplast gene in
the vast majority of samples.
GM DNA found to survive when PCR is adequate
One recent study documenting the survival of GM DNA in the mouth and
rumen of sheep was also funded by the Food Standards Agency . This research
group from Leeds University found that DNA fragments containing the entire
coding region of the synthetic cry1Ab gene was still amplifiable from rumen
fluid 5 hours after feeding maize grains, though not from rumen fluid sampled
from sheep fed silage prepared from the genetically modified maize line. But
PCR amplification of a shorter (211-bp) sequence was possible with rumen fluid
sampled up to 3 and 24 h after feeding silage and maize grains, respectively.
It is clear that GM DNA in maize grains persists, and "may, therefore,
provide a source of transforming DNA in the rumen".
But the authors are wrong to claim that the 211-bp sequence is "very
unlikely to transmit genetic information". For such sequences could be
promoters or enhancers containing hundreds of binding motifs for transcription
factors, and capable of boosting the expression of genes inappropriately.
The researchers also found that plasmid DNA introduced into the mouth of
sheep and extracted from saliva sampled after 8min was still capable of
transforming Escherichia coli bacteria to kanamycin resistance,
"implying that DNA released from the diet within the mouth may retain
sufficient biological activity for the transformation of competent oral
They conclude: "The use of GM crops harbouring antibiotic resistance
genes, in particular the use of unprocessed grains in animal feed, possibly
deserves further evaluation."
A great deal of uncertainty remains over the fate of GM DNA. Further
research must be carried out with properly validated quantitative PCR
ISIS has discovered that information on this research is not easily
found on the FSA website, although the FSA has clearly funded the research (the
research grant is G01010). The FSA website does have information on the
research they fund (there is a Research Project List for its Safety of Novel
Foods Research Programme), some with the papers themselves, others with just
short information on the projects; this is available for G01007-G01021, with
the exception of G01010 and G01014. A search of the FSA website with the term
G01010 eventually turned up some information on the project,
although not the papers arising from the research.
- Science in Parliament 2004, Spring, The Parliamentary and
- Ho MW. Living
with the Fluid Genome, Chapter 11, ISIS & TWN, London and Penang,
- Ho MW. Trangenic Lines Proven Unstable.
Science in Society
2003, 20, 35-36.
- Ho MW. Unstable transgenic lines illegal.
Science in Society
2004, 21, 23.
- Ho MW. GM maize approved on bad science in the UK.
Science in Society
2002, 15, 10.
- ACREs Response to the Chardon LL Hearing, December 2002
- Letter to Dr. Clare Pitcher, ACRE Secretariat, DEFRA, from Brian
John, GM-Free Cymru, 24 February 2004.
- Ho MW and Burcher S. Cows ate GM maize and died.
Science in Society
2004, 21, 4-6.
- Phipps RH, Deaville ER, Maddison BC. Detection of transgenic and
endogenous plant DNA in rumen fluid, duodenal digesta, milk, blood and feces of
lactating dairy cows. J. Dairy Sci. 2003, 86:JDS 3275 Take H502.
- Chowdhury EH, Kuribara H, Hino A, Sultana P, Mikami O, Shimada N,
Guruge KS, Saito M, Nakajima Y. Detection of corn intrinsic and recombinant DNA
fragments and CrylAb protein in the gastrointestinal contents of pigs fed
genetically modified corn Bt11. J Anim Sci 2003, 81, 2546-51, and
references therein; reviewed by Ho MW. Transgenic DNA and Bt toxin survive
digestion. Science in
Society 2004, 21, 11.
- Duggan PS, Chambers PA, Heritage J and Forbes JM. Fate of genetically
modified maize DNA in the oral cavity and rumen of sheep. Journal of
Nutrition 2003, 89, 159-166.