ISIS Report 07/03/08
USDA FONSI for Transgenic Poplars Absurd & Dangerous
Prof. Joe Cummins and Dr. Mae-Wan
Ho expose cavalier risk assessment that ignores existing evidence
and takes absence of evidence as evidence of absence
A fully referenced
version of this report was submitted to USDA on behalf of ISIS.
An electronic version of this report, or any other ISIS report, with full references,
can be sent to you via e-mail for a donation of £3.50. Please e-mail the title
of the report to: report@i-sis.org.uk
The Animal and Plant Health Inspection
Service of the United States Department of Agriculture
(APHIS/USDA) received a permit application (APHIS number 06–250–01r)
from Oregon State University to conduct field tests using clones of transgenic poplars
and hybrids. Permit application
06–250–01r includes trees with 95 transgenic constructs categorized only by
their intended traits, with little or no other details: reproductive sterility
genes, genes affecting stature or reduced light response, genes modifying tree physiology, and activation
tagging mutants aimed at developing “experimental domesticates”.
An Environment Assessment (EA) [1] prepared by APHIS for this permit was open
for public comment for 30 days; and on 4 February 2008 APHIS published their
evaluation of public comments and awarded the open field experiments with
transgenic poplars the verdict FONSI [2](finding of no significant impact).
Their response to public comments were aimed largely at those submitted by
the Institute of Science in Society (ISIS) [3] (Unregulated
Release of GM Poplars and Hybrids,
SiS 36), and showed that APHIS’ reviewers support field tests
particularly in areas where evidence of
safety is entirely absent or insufficient. In such areas, the
reviewers presumed that the transgenic trees are safe, and defy the public
to produce evidence of hazard,
thereby turning environmental assessment on its head. As the transgenic trees
are novel, the purpose of APHIS’ EA was to provide evidence that they are
safe, and where evidence of hazard is absent, it cannot be taken to be evidence
that hazard is absent. The review even resorted to the irrelevant remark that
Science in Society, published by ISIS, was
not a credible science source, as it was a journal of “Marxist thought and
analysis”, thereby also exposing the reviewers’ ignorance of both Marxism
and Science in Society. We challenge any rational
reader to find anything Marxist in Science
in Society. Furthermore, the articles in question are all reviews
of the scientific literature published in professional journals, which have
been ignored by APHIS.
We give some examples below.
Barnase A used in producing sterile poplars is a potent toxin
Indeed, the
toxicity of Barnase A was dismissed by just such a remark. The FONSI document
stated [2]: “APHIS disputes the claim that the toxicity of barnase to mammals
is well known. The articles the commenter cites are not from a credible science
source but from a journal of Marxist thought and analysis. As stated above,
no adverse effects to wildlife or humans are expected from expressing the
barnase in the developing flowers. Because the hazard of the protein is extremely
low and has been consumed by animals and humans with no adverse effects [no
references cited here], APHIS reasonably concludes that there should not be
a significant adverse effect on wildlife from the expression of barnase and
barstar in this GE field release.”
APHIS is wrong. Barnase is a potent
toxin. Two scientific studies listed in at least one of the Science in Society reports document that barnase is toxic
for rat kidneys at 15 ppm (parts per million) [4] and to a range of human
cells at 40 to 1000 ppb (parts per billion) [5]. It is also highly toxic for
plant cells, which is why it is used for destroying cells producing flowers
by putting it under the control of a promoter supposed to be specific for
flowering tissues. Unfortunately, the
applicants’ own research show that the promoter is not so specific for flowering
tissue, and the expression of barnase in vegetative cells had drastic effects
on plant growth and development, even when the barnase gene is accompanied
by the gene for barstar, the specific inhibitor of baranse [5]. When the barnase
gene is used to transform poplar cells without the barstar gene, no living
transformants were obtained. Thus barnase is one of the most potent cytotoxins. APHIS maintains
that barnase is present only in the flowers of the transgenic poplar, but
they are fully aware that barnase is present throughout the plant: in the leaves, roots and stems of the transgenic
poplars, and only to some extent neutralized by barstar. Animals feeding on
the stem, leaves and roots could be affected. As the leaves, stems and roots fall to the forest floor and begin
to decay, it is likely that the barnase-barstar complex will dissociate and
affect animals and microorganisms in the soil.
APHIS maintained that the use
of barnase is safe because the gene for barnase is already in some released
food crops such as maize and oilseed rape, and there have been no reports
of injury from those consuming the modified crops. However, APHIS is fully
aware that the modified crops are not labelled in the market and there have
been no scientific efforts to follow the impact of the modified food or feed
crops on human or animal populations.
Diphtheria toxin A-chain also far from safe
According
to APHIS, “There should be very limited exposure of animals to the A-chain
component of DTA. That is because the A-chain is primarily expressed in the
cells of developing flowers. During flower development there would be very
few cells expressing the protein and for only a short period of time. There
could be a very low level of expression in vegetative tissues based on the
promoter being used to drive the gene.”
Diphtheria toxin is produced normally by Corynebacterium diphtheriae when it is infected
by the phage (bacterial virus) β. The gene that codes for the toxin is
carried by the phage and is inserted into the bacterial chromosome along with
the phage genome. The active toxin gene product is cleaved into two, the A
and B chains. The A chain is the toxin that prevents protein synthesis in
the cell, thereby killing it. The B chain is necessary for the A chain to
gain access into a cell. The gene for the A chain toxin is the one inserted
into the poplar to make the trees sterile, and so it should be functioning
only within the cell that expresses the toxin.
However, there are many non-toxin producing
Corynebacterium species present
in the human population and in the general environment that may be lacking
the phage b, or else carrying a defective phage with a mutation
in the A chain. These bacteria can be transformed into active toxin producing
strains by acquiring a phage or recombining directly or via a phage with the
A chain in the poplar [6]. The chromosomal attachment sites (for the phage that carries diphtheria
toxin) of several Corynebacterium
species are identical but for a short variable section [7], and this will
facilitate horizontal gene transfer and recombination to generate toxin-producing
strains. Several Corynebacterium
species of medical importance are found in the soil, while Corynebacterium diphtheria has been found in cattle
[8]. It is clear that APHIS has ignored well documented aspects of diphtheria
toxin biology in pronouncing diphtheria toxin A chain safe.
MADS-box genes of questionable safety:
APHIS disagreed
that the introduction of an additional MADS-box gene into poplar trees should
be presumed unsafe because they are homologues of animal homeotic genes and
may be active in animals. APHIS claimed there is no scientific reason to believe
that plant MADS proteins could have a significant impact on animals.
We
shall quote from an important publication on plant MADS-box genes [9]: “ Floral homeotic genes that control
the specification of meristem and organ identity in developing flowers have
been isolated from both Arabidopsis thaliana
and Antirrhinum majus. Most
of these genes belong to a large family of regulatory genes and possess a
characteristic DNA binding domain known as the MADS-box. Members of this gene
family display primarily floral-specific expression and are homologous to
transcription factors found in several animal and fungal species.”
Homology
normally refers to similarity of DNA sequence, which means they are likely
to have similar functions. APHIS’ claim is entirely unjustified.
RNA interference ubiquitous and hazardous
According to APHIS: “..one comment points out the use of RNA interference
(RNAi) gene therapy and its potential for adverse health effects based on
studies with mice. RNAi involves the use of a small interfering double stranded
RNA of approximately 21-15 nucleotides that is complimentary to a known messenger
RNA that is used to block its expression. In this case Populus RNAi genes have been used in an attempt
to induce sterile flowers.”
APHIS’ response was: “The safety of nucleic acids is widely accepted. Both
RNA and DNA are part of all food products that we consume. “ This is a misleading
and ignorant statement of truly gigantic proportions. If all nucleic acids,
regardless of sequences were equivalent, there would be no genetics and no genetic
engineering. No wonder APHIS’ reviewers are dismissing scientific findings that
RNAi frequently has pleiotropic (i.e. unintended) effects, including death [10-12].
Small RNA molecules are now known to be ubiquitous in regulatory circuits, their
actions depending not only on sequence specificity to some extent, but also
on minutely precise timing and location of expression, which is beyond the ken
of the crude genetic engineering that can be done in the laboratory. This,
more than anything else, exposes the entire regulatory programme of APHIS to
be a complete sham, as we have documented [13].
The gibberellin gene family and phytochrome receptor genes
APHIS
commented “Thus while there is no reason to believe that the light response
and gibberellin genes will have any untoward effects, the experiment is conducted
in a way that even if they did, the material will be confined to the test
site.”
APHIS failed to refer to
any published study on transgenic phytochromes or gibberellins. There does not seem to have been any effort
to study the impact of the transgenic trees in truly contained conditions
first. There have been numerous instances where modified crops or their pollen
have escaped from open field trials. It is highly unlikely that serious untoward
consequences of gibberellins and phytochrome receptor genes or other genes
and sequences contained in the 95 constructs would be contained in an open
field trial. But this is typical of the cavalier attitude of APHIS.
Activation tagging and unintended insertion mutagenesis
Activation tagging is insertional mutagenesis,
using insertion vectors that contain a strong transcription enhancer to up-regulate
a gene near the insertion site. The insertions appear randomly in the genome, resulting in a gain
of function that represents a dominant mutation. APHIS noted the commenter (ISIS) does not believe that it is
safe for field test releases because “it is likely to cause unintended insertional
mutagenesis in a range of microorganisms and animals that interact with the transgenic
plants.” APHIS disagrees with this
comment: “The commenter did not provide any refereed citations that would
substantiate their assumption. The inserted DNA used for the
activation tagging is stably integrated into the Poplar genome. It is no more
likely to cause unintended insertional mutagenesis in another organism than
any other DNA within the Poplar. “
The activation
tagged mutants of poplar to be released in the field test were modified using
Agrobacterium to transfer the
genes for insertion and the T sequences. These mutant strains certainly bear
the T DNA border sequences typical of Agrobacterium transformation, which are special breakpoints,
i.e., recombination hotspots. It has been found that Agrobacterium T DNA can transform human cells including cancer
cells as well as kidney and neuron cells by inserting into the cells’ genome
[14]. Thus the genes transformed into poplars are certainly different from
the native poplar genes in being flanked by the borders of the T DNA, which
make them more prone to ‘break and run’, and worse yet, to re-insert into
another site in the same genome or into the genome of another cell. This possibility
has not been investigated by dedicated research. But, contrary to APHIS claim,
our comments were accompanied
by supporting references. In particular, we referred to a detailed review
on the hazards of transgenic nucleic acids including the possibilities of
insertion mutagenesis [15] (SLIPPING
THROUGH THE REGULATORY NET: ‘Naked’ and ‘free’ nucleic acids).
Horizontal gene transfer cannot be denied
The issue of horizontal gene
transfer and recombination has been raised in connection with the diphtheria
A toxin and activation tagging above. Actually, this danger is generic to
transgenic DNA, as first pointed out in some of ISIS’ earlier publications [15,
16] (Genetic Engineering Dream or Nightmare),
and more generally acknowledged since. Several of the references cited by
APHIS’ EA [1] to dismiss horizontal gene transfer actually provided the very
evidence denied. In a separate report [17] (Horizontal Gene Transfer from
GMOs Does Happen, SiS 38), we update the evidence on the horizontal transfer
of transgenic DNA from GM plants, which not only confirms that it does happen,
but also that it is greatly underestimated in bacteria, and that eukaryotic
genomes may be even softer targets for integrating transgenic DNA.
Conclusion
APHIS reviewers do not seem to be at all
well informed about the scientific literature and they have provided an uncritical
review of the application for field-testing genetically modified poplar, disregarding
all serious safety issues that we and others have raised. Opining that our
publication Science in Society is
of ‘Marxist thought
and analysis’ and ignoring the fact that the articles were reviews of the
scientific literature is simply adding insult on injury. This comment seems
to be the off-hand response of some dim-witted bureaucrat, but could in reality serve as a threat to all
who participate in APHIS’ public comment. Such comments from a government
bureaucracy though groundless, is not to be taken lightly, as it can trigger
wide-ranging government actions in the name of counter-terrorism that may
include travel restrictions and other invasive measures. APHIS
should withdraw the FONSI ruling from the poplar field tests. And we must
demand that APHIS retract the
comment on Science in Society
being of “Marxist thought and analysis.”
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