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TWN Biotechnology & Biosafety Series 1
Fatal Flaws in
Food Safety Assessment:
Critique of the
Joint FAO/WHO
Biotechnology &
Food Safety Report
by Mae-Wan Ho
and Ricarda A Steinbrecher
TWN
Third World Network
Fatal Flaws in Food Safety AssessmentCritique of The Joint FAO/WHO Biotechnology
and Food Safety Report
Mae-Wan Ho
&
Ricarda A Steinbrecher
TWN
Third World Network
Penang, Malaysia
|
Fatal Flaws in Food Safety Assessment:
Critique of The Joint FAO/WHO Biotechnology and
Food Safety Report
is published by
Third World Network
228 Macalister Road
10400 Penang, Malaysia.
copyright © Third World Network 1998
First Printing: 1998
Second Printing: 1999
Third Printing: .2002
This is part of a series of papers on biotechnology and biosafety that the
Third World Network is publishing with a view to deepening public
understanding on the ecological and safety aspects of the new
biotechnologies, especially genetic engineering.
Printed by Jutaprint
2 Solok Sungei Pinang 3, Sg. Pinang
11600 Penang, Malaysia.
Contents
Summary
1
Chapter 1.
Introduction
Chapter 2.
Biased Partisan Claims for the Technology 9
Chapter 3.
Failure to Take Responsibility for Major
Aspects of Food Safety
7
11
3.1 Environmental impacts
3.2 Production of pharmaceuticals and industrial
chemicals in food
3.3 Labelling and monitoring
Chapter 4.
Chapter 5.
Restriction of Scope Exempts Known
Hazards from Safety Assessment
Erroneous Claim that Genetic Engineering
is the Same as Conventional Breeding
17
5.1
Chapter 6.
15
New hazards are inherent in genetic
engineering biotechnology
The Principle of Substantial Equivalence
is Unscientific and Arbitrary
The principle is intentionally vague and illdefined so as to be as flexible, malleable and
open to interpretation as possible
6.2 Comparisons are designed to conceal
significant changes resulting from genetic
modifications
6.1
23
6.3
6.4
6.5
6.6
6.7
6.S
Chapter 7.
The principle is weak and misleading even
when it does not apply, effectively giving
producers carte blanche
Insufficiency of background information for
assessing substantial equivalence
There is no specification of tests for establishing
substantial equivalence
There is no requirement to test for unintended
effects, current tests are undiscerning and may
even serve to conceal unintended effects
The spread of antibiotic-resistance marker genes
by horizontal gene transfer is downplayed, by
ignoring scientific evidence
There is no consideration of unintended gene
transfers in the general environment
Failure to take existing scientific evidence
into account
39
7.7
7.2
7.3
7.4
7.5
7.6
7.7
The instability of transgenes and transgenic lines
The prevalence and scope of horizontal gene
transfer in all environments, including the
gastrointestinal tract
DNA is not readily degraded in the environment
Transgenic bacteria, even those that are
"biologically crippled", may survive and multiply
in the environment
Horizontal gene transfer is now known to be
responsible for spreading antibiotic resistance
and virulence among pathogens
The ability of viral DNA to survive digestion
in the gut
The ability of recombinant vectors to invade
mammalian cells
7.8 Recombination between viral transgenes and
viruses generates siiperinfectious viruses
7.9 Antibiotics promote horizontal gene transfer
Chapter 8.
Chapter 9.
A 'safety assessment' designed to
expedite product approval with little or
no real regard for safety
47
Recommendations
49
Endnotes
52
References
53
Summary
The Biotechnology and Food Safety Report issued jointly by the
Food and Agriculture Organization (FAO) and World Health Or
ganization (WHO), is the result of an Expert Consultation held in
Rome, in October 1996. The Consultation was the latest, possibly
the most significant, attempt to reach international agreement on
the safety of genetically engineered (GE) food. If accepted, it will
set international safety standards to be adopted by WHO's Codex
Alimentarius Commission, which will determine, not only GE food
safety, but also world trade of GE foods. It will be illegal for any
country to ban GE food imports, so long as the Codex considers
them safe.
The FAO/WHO Report shows up the glaring inadequacies in
safety regulation of GE foods, designed to expedite product ap
proval with little or no regard for biosafety. It is a case of 'don't
need - don't look - don't see', effectively giving producers carte
blanche to do as they please, while serving to diffuse and allay le
gitimate public fears and opposition.
The 'principle of substantial equivalence', on which all safety
assessment is based, is completely unscientific and arbitrary. A
GE product assessed to be substantially equivalent (SE) is regarded
as safe and fit for human consumption. But the principle is not
only vague and ill-defined, it is flexible, malleable and open to in
terpretation. 'Substantial equivalence' does not mean an equiva
lence of the unengineered plant or animal variety. The GE food
could be compared to any and all varieties within the species. It
1
could have the worst characteristics of all the varieties and still be
considered SE. A GE product could even be compared to a prod
uct from a totally unrelated species. Worse still, there are no de
fined tests that products have to go through to establish substan
tial equivalence. The tests are so undiscriminating that unintended
changes, such as toxins and allergens, could easily escape detec
tion. AGE potato, grossly altered, with deformed tubers, was nev
ertheless tested and passed as SE.
The Consultation explicitly failed to assume responsibility for
major areas of GE food safety, such as labelling and monitoring;
impacts on biodiversity; and the control of traditional food crops
engineered to produce pharmaceuticals and industrial chemicals.
The latter will readily cross-pollinate with unmodified food plants
and contaminate global food supply for years to come. Also left
out are pesticide residues in food crops engineered to be resistant
to herbicides, hormone residues and veterinary drugs in BST (or
bovine somatotropin) milk from cows fed with this GE bovine
growth hormone, which have to be treated for subsequent stress
and infections.
Much more serious is a list of gruesome products that will appear
on our dinner table, if the Report goes unchallenged: a range of
'transgenic wastes' from GE plant residues after engineered indus
trial chemicals and pharmaceuticals have been extracted, meat from
failed GE experimental animals or from animals engineered to pro
duce drugs and human proteins in their milk (e.g. Tracy, the
transgenic sheep), meat from pigs engineered with human genes
for organ transplants, and crops sprayed with insecticidal GE
baculoviruses. The baculovirus is simultaneously engineered by
medical geneticists to transfer genes into human liver cells because
the virus is particularly good at invading those cells.
The possibility of new viruses being generated and of genes
jumping (horizontally) across species barriers, as the result of
2
GE biotechnology itself, is real, especially in the light of recent
scientific findings. The FAO/WHO Report ignores these findings,
and sidesteps the whole issue by still maintaining that there is no
difference between genetic engineering and conventional breed
ing methods. The Report is openly partisan to the technology,
making unsubstantiated claims for its benefits while omitting to
mention the socioeconomic impacts on small farmers, and the vi
able alternatives to the technology in all forms of sustainable agri
culture already practised worldwide.
Recommendations
In view of the gross inadequacies in food safety regulation and the
scientific evidence pointing to serious hazards, we recommend a
number of measures to safeguard the health of consumers and to
protect biodiversity. The precautionary principle also demands that
a moratorium on further releases should be imposed until the fol
lowing measures are implemented.
a.
No food crops are to be engineered for producing pharma
ceuticals and industrial chemicals, as the engineered crops
could be mistaken for food, or cross-pollinate with non-engineered food crops. The onus must be on the producer to prove
that any plant genetically engineered is not a food crop.
b.
All projects involving genetic manipulation of baculovirus for
insecticidal purposes should be discontinued, as this virus is
being used in human gene therapy and invades human liver
cells readily.
c.
Complete characterization of inserted gene sequence(s) of the
genetically engineered organism (GEO) must be provided in
the application for market approval. This should include any
antibiotic-resistance marker gene(s), promoter(s) and
enhancer(s) and their effects on the expression of neighbour-
3
ing genes. The presence of mobile genetic elements and other
proviral sequences in the host genome, likely to contribute to
secondary mobility of inserts, must also be stated.
d.
No GEOs with uncharacterized foreign gene inserts are to be
considered for release. No parts of such GEOs, nor of animals
from failed experiments in genetic engineering or
xenotransplant animals are to be used as human food or ani
mal feed.
e.
No GEOs containing antibiotic-resistance genes are to be con
sidered for release or to be used as human food or animal
feed.
f.
A detailed record of the stability of the GEO over at least five
successive generations under field conditions (including
drought and heat) is a precondition for market approval.
("Field conditions" does not mean open field conditions.) This
must be supported by appropriate data indicating the stabil
ity of the insert as well as the level of gene expression under
different conditions in successive generations.
g.
Data on the frequency of unintended gene transfers, includ
ing horizontal gene transfer from the GEO under field condi
tions, must be included in the application for market approval.
h.
Data on the frequency of horizontal gene transfer from the
GEO to gut bacteria must be included in applications for mar
ket approval.
i.
Data on the ability of transgenes and marker genes in the GEO
to invade mammalian cells must be included in applications
for market approval.
j.
A specified set of tests must be carried out to establish "sub
stantial equivalence", which are sufficiently discerning to re-
4
veal unintended as well as intended effects. The comparator
must be the unmodified recipient organism itself, and results
of repeated tests must be provided to support the stability of
the characteristics over at least five successive generations.
k.
Safety assessment must include the GEO's potential to gener
ate pathogens through genetic recombination.
1.
Safety assessment must include pesticide residues where they
are integral components of the product, as in herbicide-resist
ant transgenic plants.
m.
Product segregation, labelling and postmarket monitoring are
non-negotiable conditions for market approval.
5
Chapter 1
Introduction
The Report on Biotechnology and Food Safety - resulting from
the Joint Expert Consultation held by the Food and Agriculture
Organization/World Health Organization in Rome from 30 Sep
tember to 4 October 1996 - is the latest, possibly most significant,
attempt to reach international consensus on principles and proce
dures for the evaluation of safety of food produced by genetic en
gineering biotechnology. It will set international food safety stand
ards to be adopted by WHO's Codex Alimentarius Commission,
which will, in turn, have enormous implications for biosafety and
for the world trade of genetically engineered foods. For example,
it will be illegal for any country to ban the import of genetically
engineered foods that are considered safe by the Codex. Regretta
bly, the Report reflects and perpetuates the gross inadequacies of
current regulatory frameworks:
•
•
•
•
•
It openly favours the technology, making contentious claims
for its benefits.
It fails to assume responsibility for major aspects of food safety,
such as environmental impacts, control of traditional food
crops being used for pharmaceutical and industrial chemical
production, labelling and monitoring.
It exempts known hazards from safety assessment by restrict
ing the scope of safety considerations.
It takes as a premise the erroneous claim that genetic engi
neering does not differ from conventional breeding.
Its principle of substantial equivalence, on which all safety
assessment is to be based, is arbitrary and unscientific.
7
•
•
It fails to address long-term impacts on health and food secu
rity.
It ignores existing scientific findings pointing to identifiable
hazards.
The result is a 'safety assessment' exercise designed to expedite
product approval with little or no real regard for safety.
8
Chapter 2
Biased Partisan Claims for the Technology
The FAO/WHO Report claims that biotechnology accelerates the
development of 'better foods', that its benefits are many. These in
clude providing resistance to crop pests, reducing chemical pesti
cide usage - 'thereby making major improvements in both food
quality and nutrition' (p.l). We are told that the use of
biotechnological processes, particularly genetic modification, 'is
extremely important in devising new ways to increase food
production...[and] improve nutrient content' (p.2). Further on, the
Report claims that '[r]ecombinant DNA technology has broad ap
plication in developing countries and has the potential for very
positive impact on their economies...' (p.21). This typical propa
ganda of the biotech industry has never been backed up by any
evidence, and has no place in a safety report.
Herbicide tolerance and insect resistance are the two most com
mon genetically engineered traits, currently accounting for 54% and
37% respectively of the global area planted with transgenic crops,
while viral resistance occupies 14% and quality traits less than 1%
(James, 1997).
None of the traits constitute 'major improvements in food quality
and nutrition'. On the contrary, each major category carries its own
risks for health and biodiversity, some more than others. Herbi
cide-resistant transgenic crops are used with a companion herbi
cide; for example, Monsanto has engineered a wide range of crop
plants resistant to its top-selling herbicide, the glyphosate-based
'Roundup', which is toxic to animals and human beings as well as
9
plants (Cox, 1995). Natural insecticides, while safe at the low con
centrations found in nature, may be harmful at the high concentra
tions produced in resistant transgenic plants (Cummins, 1996),
while viral-resistant transgenic plants are found to regenerate in
fectious viruses at high frequencies (Allison, 1997). We shall go
into the hazards in greater detail later on.
The claims of benefits to the environment are particularly ques
tionable as the Report specifically excludes environmental consid
erations from its remit, thereby avoiding any challenge to the claims
(see below). These claims are downright misleading when no men
tion is made of already viable alternatives to increase food produc
tion by sustainable agricultural systems all over the world
(Reganold et al., 1990; Ho, 1997a, Chapters 2 and 9) nor of the seri
ous socioeconomic impacts of the technology on small peasant
farmers worldwide under the monopolistic regime of corporate
intellectual property rights and the new world trade laws (Simms,
1997).
10
Chapter 3
Failure to take Responsibility for Major
Aspects of Food Safety
The Report has disclaimed responsibility for several major aspects
of food safety, which we shall deal with in turn.
3.1
Environmental impacts
'The Consultation further did not consider environmental safety
issues related to the release of food organisms, foods or food com
ponents produced using biotechnology, into the environment as
these were outside its defined scope' (p.3). On the previous page
we are told that in the opinion of Professor Giuliano D'Agnolo,
whose Institute hosted the Consultation, 'the environmental issues
related to biotechnology have been well defined...' (p.2).
Contrary to Professor D'Agnolo's assertion, the environmental is
sues related to biotechnology have not been well defined. They
have simply been ignored, and continue to be side-stepped by the
Report.
The hazards of transgenic plants are by now well recognized (see
Ho, 1996; Steinbrecher, 1996). Plants engineered to be resistant to
broad-range herbicides will result in indiscriminate killing of a
whole range of other plants over vast areas which are important
constituents of natural ecosystems, besides the poisoning of hu
man beings and animals, when the herbicides are applied. Simi
larly, the toxin from soil bacterium, Bacillus thuringiensis (Bt), is en
gineered into plants in a less selective form that is harmful, not just
11
to pests but also to non-target beneficial insects such as bees (Crabb,
1997). Recent reports indicate that beneficial insects which control
pests, such as lacewings and ladybirds, may also be killed or harmed
on ingesting pests that have eaten Bt-transgenic crop-plants (Bigler
and Keller, 1997; Hawkes, 1997). Furthermore, herbicide-resistant
weeds and insecticide-resistant pests are known to evolve rapidly
in the field. And superinfectious viruses can be generated from a
range of plants engineered to be viral-resistant (see Section 2).
Another environmental hazard from genetically engineered crops
is the unintended spread of genes by cross-pollination and by hori
zontal gene transfer (see Section 7.2).
3.2 Production of pharmaceuticals and industrial chemicals in
food
'The Consultation agreed that the safety assessment of pharma
ceuticals and industrial chemicals, as such, was outside its remit...
the Consultation recognized that the genetic modification of food
organisms to produce pharmaceuticals or industrial chemicals may
raise ethical and control issues that were outside its remit because
the issues were unrelated to food safety' (p.20).
On the contrary, the use of traditional food crops and animals for
producing pharmaceuticals and industrial chemicals is a serious
food safety issue that ought to be addressed by the Report. Genes
producing the pharmaceuticals or chemicals could easily spread
by cross-pollination to ordinary food crops and lead to widespread
contamination of the world food supply for years to come. Be
cause these products are cryptic, neither farmers nor consumers
will be able to tell the difference without the appropriate tests.
Additional hazards will come from the spread of genes by hori
zontal gene transfer through aphids and other insects which feed
on the crops, through bacteria in the soil, and above ground (see
Sections 6.7. 6.8 and 7.5). The hazards from 'pharm' animals used
for pharmaceutical production will be addressed in Section 6.3.
12
3.3
Labelling and monitoring
'The Consultation also did not consider any issues regarding the
labelling of such foods or food ingredients...' (p.3). Monitoring,
though not explicitly excluded, is not mentioned at all in the Re
port. These omissions betray a blatant disregard for safety in view
of the many identified hazards already excluded from the remit of
the Consultation. Genetic engineering biotechnology is still largely
untried and inadequately researched. It has been prematurely
rushed to market against the wishes of the vast majority of con
sumers. In the absence of labelling and postmarket monitoring, it
will be almost impossible to identify the sources of hazards, to pro
tect consumers accordingly, or to take appropriate remedial action.
13
Chapter 4
Restriction of Scope Exempts Known
Hazards from Safety Assessment
The FAO/WHO Report further excludes from consideration, 'in
cidental residues in food resulting from the use of processing aids,
or derived from the use of chemicals such as pesticides and veteri
nary drugs during food production' (p.3).
As a large proportion of current transgenic crops are herbicide
resistant, with a companion herbicide being sold and used as part
and parcel of the package, it is not legitimate to exclude from con
sideration residues derived from the use of the herbicide. But
that was precisely what took place in the safety assessment of
Monsanto's Roundup-resistant soya bean. It was assessed without
herbicide application (Tappeser and von Weizsacker, 1996). Soya
bean is known for producing phytoestrogen and to date, no tests
have been performed to assess the level of estrogen in genetically
engineered soya subject to the kind of repeated applications of
Roundup that would take place when grown in the field.’ Apart
from the inherent toxicity of the herbicide, previous research has
shown that herbicide spraying can increase the concentration of
phytoestrogens (Sandermann and Wellmann, 1988).
Coincidentally, milk produced from cows fed with Monsanto's
genetically engineered bovine somatotropin (BST milk) was also
not assessed for hormone residues other than BST, nor for antibiot
ics which were fed to the cows to overcome mastitis and other in
fections arising from the use of BST. It is significant that the Codex
Alimentarius Commission failed to pass a vote to permit the use of
BST in June 1997, although it has been marketed since 1994.2
15
Even more serious is the exclusion of 'food-borne pathogens' (p.3).
It has now been well documented that new, superinfective viruses
can be generated in the many transgenic plants which have been
made 'viral resistant' by incorporating the coat-protein and other
viral genetic material (e.g. satellite RNA or ribonucleic acid). This
is due to recombination between viral transgene(s) and co-infecting viruses (Anderson et al., 1992; Green and Allison, 1994;
Palukaitis and Roossinck, 1996; Allison, 1997). The US Department
of Agriculture is deliberating restrictions on this category of
transgenic plants (Kleiner, 1997). Recombination by similar mecha
nisms is predicted for another viral sequence, the cauliflower mo
saic virus promoter, which is routinely used to boost the expres
sion of transgenes (i.e., the foreign gene) in transgenic plants, al
though experiments have not yet been carried out to investigate
this possibility (Cummins, 1994). The exclusion clause effectively
exempts these products from safety assessment for food-borne
pathogens that arise from the transgenic technology itself.
Also exempt are a range of genetically engineered baculoviruses,
which have been developed for controlling insect pests (Jehle, 1997).
This case needs urgent attention, as baculoviral vectors are con
currently being developed for human gene replacement therapy
because these vectors appear to be particularly good at invading human
liver cells (Heitmann and Lopes-Pila, 1993; Hofmann et al., 1995;
Sandig et al., 1996). Yet, there is no mention of baculovirus in the
entire Report.
16
Chapter 5
Erroneous Claim that Genetic Engineering
is the Same as Conventional Breeding
Jrood safety considerations regarding organisms produced by
techniques that change the heritable traits of an organism, such as
rDNA technology, are basically of the same nature as those that
might arise from other ways of altering the genome of an organ
ism, such as conventional breeding' (p.3).
The blurring of the distinction between genetic engineering and
conventional breeding - a position adopted by the producers and
regulators alike - is the single most important reason for the per
sistent failure of regulatory systems to protect consumers and
biodiversity. Genetic engineering carries its own inherent hazards which
are unique to it, and which must be taken into proper account if we are to
really protect health and biodiversity.
5.1 New hazards are inherent in genetic engineering
biotechnology
The unique hazards of genetic engineering have been dealt with in
more detail elsewhere (Ho, 1995, 1997a; Antoniou et al., 1997; Ho
and Tappeser, 1997). We reiterate them and extend the discussion
below.
a.
The technology transfers exotic genes to organisms - genes
for which no equivalents (alleles) may exist in the genome of
the recipient organism - and are, therefore, more likely to have
unexpected physiological and metabolic effects.
17
b.
The method of gene transfer involves random insertions of
the gene(s) into the genome (Walden et al., 1991), causing cor
respondingly random genetic effects. In transformation with
Agrobacterium T-DNA (the T is for Tumour, from the Tumour
inducing plasmid), the most widely used system for plants,
the complete vector may be inserted, or a truncated or rear
ranged form, in single copies or tandem repeats at one or more
sites; and insertion mutagenesis (due to insertion within other
genes) is relatively common (see Conner, 1995).
c.
Special promoter sequences and sometimes enhancers (often
from disease-causing viruses) are included with the introduced
gene(s) to boost constitutive (continuous) expression, and to
effectively place the gene(s) outside regulation by the host cell.
These promoters and enhancers are very strong, and are likely
to affect the expression of neighbouring genes in the host
genome.
On account of (a), (b) and (c), many unintended metabolic and ge
netic changes can result from the gene transfer, and grossly abnor
mal transgenic plants and animals have been generated, as well as
toxins and allergens (see below).
d.
18
The technology depends on artificially constructed invasive
vectors for carrying genes, which are mosaics of different ge
netic parasites with the ability to invade cells of different spe
cies, multiply in them, or insert themselves into the genome.
These vectors are designed to deliver genes into cells and to
overcome cellular mechanisms that destroy or inactivate for
eign DNA (deoxyribonucleic acid). They are, therefore, ex
pected to be particularly good at transferring genes horizon
tally between unrelated species, and will do so whether in
tended or not. Although their mobility function has been re
moved, they can be moved by 'helper-functions' supplied by
other parasitic genetic elements that are present in all genomes.
There is already direct evidence of secondary (horizontal) gene
transfers from transgenic plants to a bacterial pathogen
(Schluter et al., 1995)3 and to soil fungi (Hoffman et al., 1994).
And these are the only experiments that we know of, which
have been carried out specifically to investigate horizontal
gene transfer.
e.
Many gene-transfer vectors are derived from viruses that cause
diseases or bacterial plasmids or transposons (mobile genetic
elements) that carry antibiotic-resistance and virulence genes,
with their virulence functions removed. However, these gene
transfer vectors may recombine with viruses and plasmids in
the host cells to generate new pathogens (Allison, 1997). As
mentioned earlier, new superinfective viruses are generated
by recombination between viral transgenes and infecting vi
ruses. There is also evidence that while recombination be
tween unmodified viruses may be negligible, modified, ma
nipulated viral genomes are much more prone to undergo
further recombination (Allison, 1997; Ho, 1997a; Ho et al., 1997).
This raises questions on the safety of gene-transfer vectors
which are practically all modified hybrid genomes of viruses,
plasmids and mobile genetic elements. This topic alone re
quires thorough investigations which have yet to be carried
out.
f.
Most of the gene-transfer vectors carry antibiotic-resistance
markers to enable transformed cells to be selected, and these
marker genes are routinely left in the transgenic organisms
constructed.
The special characteristics inherent to genetic engineering
biotechnology, (d), (e) and (f), have to be seen in the context of the
current crisis in public health identified by WHO's own 1996 Re
port - the emergence of old and new infectious diseases which are
resistant to treatment by drugs and antibiotics. Furthermore, there
is now abundant evidence that horizontal gene transfer and re
combination have been responsible for the rapid spread of both
19
virulence and antibiotic resistances, as we shall examine in more
detail in Section 7.5.
In contrast to genetic engineering, conventional cross-breeding
usually involves related species, often recombining different forms
of the same genes (alleles). These species may have different num
bers of chromosomes that differ in gene sequences. Redundant
chromosomes or chromosomes that do not have a homologous
partner are either lost during cell division or become inactivated
by normal cellular mechanisms. Partially homologous chromo
somes cause problems in the formation of germ cells and are most
likely to lead to sterility of the hybrid. In such cases, induced
polyploidy (causing the entire complement of chromosomes to
double) is the usual method for ensuring reproductive success of
the hybrid, as this restores normal chromosome pairing during
germ-cell formation. Polyploidy generally results in an overall in
crease in size. It may result in changes in metabolism, and the
polyploid hybrid should also be assessed for safety with sufficient
rigour. The main differences, however, are that there are no intro
duced invasive vectors that can insert at random into chromosomes which
can potentially undergo secondary movements, nor antibiotic-resistance
marker genes, nor strong promoter or enhancer sequences that continu
ously switch on gene expression, placing the genes outside cellular con
trol.
Thus, there are clear differences between genetic engineering and
conventional breeding. Furthermore, there are already identifiable,
if not quantifiable, hazards inherent in current practices of genetic
engineering which make adherence to the precautionary principle
in food safety paramount. Instead, the Consultation fails to ad
dress those hazards, and worse, effectively excludes them from
consideration by the seemingly innocuous sentence, 'The presence
in foods of new or introduced genes per se was not considered by
the Consultation to present a unique food safety risk since all DNA
is composed of the same elements' (p.4). This statement is nonsen
sical, as it is the sequence of the DNA which makes all the differ
20
ence, especially between a pathogen and a non-pathogen. In addi
tion, it is the special combination of sequences, the form of the DNA,
as an invasive vector capable of secondary mobilization and re
combination - with its aggressive promoter and enhancer sequences
and antibiotic-resistance marker genes - that makes all the differ
ence between food obtained from conventional breeding and ge
netically engineered foods.
21
Chapter 6
The Principle of Substantial Equivalence is
Unscientific and Arbitrary
The most serious shortcomings of the FAO/WHO Report stem
from the principle of 'substantial equivalence' on which all safety
assessment is based.
6.1 The principle is intentionally vague and ill-defined so as to
be as flexible, malleable and open to interpretation as possible.
'Substantial equivalence embodies the concept that if a new food
or food component is found to be substantially equivalent to an
existing food or food component, it can be treated in the same
manner with respect to safety (i.e., the food or food component can
be concluded to be as safe as the conventional food or food compo
nent)' (p.4).
This principle is unscientific and arbitrary, encapsulating a dan
gerously permissive attitude towards producers. At the same time
it offers less than minimalist protection for consumers and
biodiversity, because it is designed to be as flexible, malleable and
open to interpretation as possible.
'Establishment of substantial equivalence is not a safety assessment
in itself, but a dynamic, analytical exercise in the assessment of the
safety of a new food relative to an existing food.... The comparison
may be a simple task or be very lengthy depending upon the
amount of available knowledge and the nature of the food or food
component under consideration. The reference characteristics for
23
substantial equivalence comparisons need to be flexible and will
change over time in accordance with the changing needs of proc
essors and consumers and with experience' (pp. 4-5).
In other words, one can choose to compare whatever is the most
convenient at a particular time, and for a particular purpose. And
if on one set of criteria, the product is not substantially equivalent,
a different set of criteria could be used, always to the advantage of
the producers.
6.2 Comparisons are designed to conceal significant changes
resulting from genetic modifications
In practice, the principle allows comparison of the transgenic line
to any variety within the species, and even to an abstract entity
made up of the composite of selected characteristics from all vari
eties. This is exemplified in the safety evaluation reported by the
company Calgene on several of their products (Redenbaugh et al.,
1995). By a judicious use of additional varieties any changes from
the control recipient variety could be bracketed. In theory, a ge
netically engineered line could have the worst features of every
variety and still be substantially equivalent. Such comparisons ac
tually conceal significant changes resulting from the genetic modi
fication per se, which should alert conscientious researchers to a
more careful characterization of the genetically modified organ
ism.
Bernard Shaw was reputed to have been propositioned by a beau
tiful though not-too-bright lady who wanted to have his child so
that it would have his brains and her looks. But Shaw was said to
have discouraged her by pointing out that the child could end up
having her brains and his looks instead. So, it is the particular com
bination of characteristics that makes all the difference. But under
the present safety assessment regime, both combinations would
be deemed 'substantially equivalent'. The danger is that particu
lar combinations of nutrients or metabolites might fall within the
24
'equivalent' range determined in this fashion, and yet be anti-nutritional or outright lethal or toxic.
And if that were not enough, producers are assured that, even when
products are not substantially equivalent, they can be shown to be
substantially equivalent except for defined differences, and 'fur
ther safety assessment should focus only on those defined differ
ences' (p.8). Lest one is in any doubt, it is stated on p.ll that, '[u]p
to the present time, and probably for the near future, there have
been few, if any, examples of foods or food components produced
using genetic modification which could be considered to be not
substantially equivalent to existing foods or food components.'
Calgene's genetically engineered Laurate canola oil should, by no
stretch of the imagination, be considered substantially equivalent
to ordinary canola oil. But, 'other fatty acids components are GRAS
[Generally Recognized as Safe] when evaluated individually be
cause they are present at similar levels in other commonly con
sumed oils.' Similarly, 'substitution of Laurate canola for coconut
and palm kernel oils does not raise any safety concerns for intended
uses, in part because the major components, the fatty acids laurate
and myristate, are identical' (Redenbaugh et al., 1995, p.43).
In other words, it is already a foregone conclusion that most, if not
all, products now and for the foreseeable future will be assessed as
'substantially equivalent' and if not, then considered GRAS by a
judicious choice of a comparator.
It is significant that the Dutch courts recently ruled Monsanto's
genetically engineered soya beans not equivalent in quality to natu
ral soya beans, as was claimed in the advertisement of Albert Heijn,
the biggest supermarket chain in the Netherlands. Albert Heijn is
itself part of the Dutch multinational, Ahold, which owns super
market chains in many countries around the world. The complaint
was filed by the Dutch Natural Law Party (Storms, 1997).
25
6.3 The principle is weak and misleading even when it does
not apply, effectively giving producers carte blanche
Given that 'substantial equivalence' can be interpreted in the wid
est possible sense - and if not, by a judicious choice of comparator
- in order that a product can be considered as GRAS, it is difficult
to imagine which remaining products cannot pass muster.
The Report recognized that 'products could be developed which
could be considered to have no conventional counterpart and for
which substantial equivalence could not be applied' (p.ll). For ex
ample, 'products derived from organisms in which there has been
transfer of genomic regions which have perhaps been only partly
characterized' (p.ll). This gives the impression that such are hypo
thetical cases that might arise in future.
But that is not so. The Report failed to point out that at least one
such transgenic organism already exists: Tracy, the sheep engineered
with a large segment of the human genome - most of which con
tains unknown sequences with unknown functions - to produce
huge quantities of alpha-antitrypsin in her milk (Colman, 1996).
Tracy and her clones may be walking incubators for cross-species
viruses to arise by recombination between human and sheep viral
sequences. All genomes contain endogenous proviral sequences,
and recombination between endogenous and exogenous viral se
quences is already implicated in several kinds of animal cancers
(see Ho, 1997a, Chapter 13). One might think that the Report would
treat such cases with extra caution. Not so.
We are assured that even if a food or food component is consid
ered to be not substantially equivalent, producers need not despair,
for 'it does not necessarily mean it is unsafe and not all such prod
ucts will necessarily require extensive testing' (p.12). The Report
is clearly preparing the grounds for slipping those products through
a regulatory framework that is already worse than toothless.
26
Further on, in Section 6.6 on 'Food organisms expressing pharma
ceuticals or industrial chemicals' (p.19), there is the telling state
ment, 'The Consultation recognised that, generally, the genetically
modified organism would not be used as food without prior re
moval of the pharmaceutical or industrial chemical' (p. 19). This is
a prelude to serving up the rest of Tracy and the 'elite herd' cloned
from her, or more likely, superannuated 'pharm' animals and any
failed transgenic experiment, whatever, as meat for our dinner ta
bles. Transgenic technology is very inefficient and generates a lot
of transgenic wastes - given the large numbers of failed experi
ments. Such 'foods' from transgenic wastes may be sources of ex
otic, cross-species food-borne viruses, as mentioned earlier. Fur
thermore, they will be exempt from safety assessment if the Report
is to be taken seriously. A similar category of transgenic waste could
be the left-over carcasses of pigs engineered for xenotransplantation.
All the signs are that the producers are handed carte blanche to do
as they please for maximum profitability, with the regulatory body
acting to allay legitimate public fears and opposition.
6.4 Insufficiency of background information for assessing sub
stantial equivalence
The procedure for establishing substantial equivalence, described
in less than three pages in the 27-page Report (pp.6-8), comes un
der two headings: background information on the characterization
of the modified organism and actual determination of substantial
equivalence, or characterization of the food product itself.
One glaring omission in the background information is the pro
pensity of the transgenic organism for generating pathogenic vi
ruses by recombination (and whether experiments have been car
ried out to investigate this propensity). This information is highly
relevant for assessing impacts on biodiversity as well as food safety,
in view of our current knowledge that superinfecting viruses may
27
be generated from many transgenic plants at high frequencies and
that insecticidal recombinant viruses may attack human liver cells.
There is also disturbing new evidence that viral DNA can survive
digestion in the gastrointestinal tract of mice, with large fragments
getting into the bloodstream and into many kinds of cells (Schubbert
et al., 1994).4
Likewise, information on the stability of transgenes, and potential
for mobility of introduced genes, which are mentioned on p.6 of
the Report, ought to be based on data collected over a number of
generations, documenting the stability of the insert as well as ex
pression of the transgenes and the transgenic line in successive
generations. This is so that both consumers and farmers can have
confidence in quality control. In a paper presented at a WHO work
shop, the author states, 'The main difficulty associated with the
biosafety assessment of transgenic crops is the unpredictable na
ture of transformation. This unpredictability raises the concern
that transgenic plants will behave in an inconsistent manner when
grown commercially' (Conner, 1995, p.27).
In general, the inheritance of genetically engineered traits are nonMendelian in subsequent generations (Schuh et al., 1993) necessi
tating clonal propagation. In early 1997, 60,000 bags of genetically
engineered canola seeds, enough for planting 600,000 acres, had to
be recalled after they were sold in western Canada, because an
unexpected gene, not yet approved for market, turned up in the
seeds. The seeds were bred and sold by Limagrain, under licence
from Monsanto.5 If the transgenic plants had been monitored for
genetic stability of both the transgenes and the transgenic line in
successive generations-as they should have been - and careful records
kept, those seeds would never have reached the market. This inci
dent also indicates the necessity for product segregation, clear la
belling and postmarket monitoring as part of the condition for
market approval.
28
Under background information, it is also crucial to include the
upstream and downstream effects of transgenic promoter and en
hancer sequences, as well as the presence of genetic elements in
the host that might compromise the stability of the transgenes.
A further serious omission in the background information is the
explicit requirement to disclose the presence of marker genes, es
pecially antibiotic-resistance marker genes which are considered
in Section 6.7.
6.5 There is no specification of tests for establishing substan
tial equivalence
Under 'characterization of the food product', we are told it entails
'molecular characterization', 'phenotypic characterization' and
'compositional analysis'. While the latter two categories are elabo
rated subsequently, 'molecular characterization' has mysteriously
disappeared. Nowhere is it specified which methods of molecular
characterization are required, nor which molecular information
should be established. Such information happens to be crucial for
identifying unintended effects. Similarly in a previous document
which reports on a WHO Workshop on the principle of substantial
equivalence,6 molecular characterization is left very vague. It re
fers to 'the inserted DNA'; 'the level and mechanism of expression
of the protein', which is considered to be 'more important than
knowing the gene copy number'. In other words, the inserted DNA
sequence need not be well characterized at all. The WHO's Work
shop Report then mentions that 'the level and function of the in
troduced gene product in the plant may be useful in judging sub
stantial equivalence', again implying that the function of the gene
product need not be known as a condition for safety approval. If
the gene(s) and gene product(s) transferred are well understood,
however, the safety evaluation can then 'focus on the safety of the
expression product and/or changes brought about by the expres
sion product'. This is an open endorsement of a totally inadequate,
29
reductionist safety assessment that ignores effects on the system as
a whole, especially in the longer term.
In effect, no molecular characterization of the product whatsoever
is required. Not even the level of expression of the introduced
transgene(s) or marker gene(s) need to be ascertained, much less
the effects of promoters and enhancers on neighbouring genes, as
judged by the samples of papers presented in the WHO workshop
on substantial equivalence.7 If one happens to know what has been
transferred, then the safety assessment can focus only on the gene
product and its effects. So the two main categories of characteriza
tion of the food product are, simply, phenotypic characteristics:
• agronomic, morphological and physiological and compositional
comparison
• key nutrients and toxicants which are known to be inherently
present in the species.
6.6 There is no requirement to test for unintended effects, cur
rent tests are undisceming and may even serve to conceal unin
tended effects
Although the FAO/WHO Report recognizes the possibility of 'in
direct consequences' (p.4) and that 'assessment of the safety of ge
netically modified organisms must address both intentional and
unintentional effects that may result as a consequence of the ge
netic modification of the food source' (p.5), these effects are lim
ited to phenotypic changes that are readily apparent, and altera
tions in the concentrations of major nutrients or increases in the
level of natural (known) toxicants. There is thus no specific re
quirement to test for unintended effects, per se.
Similarly, while it is stated that 'attention must be paid to the im
pact of growth conditions on the level of nutrients and toxicants ...
attention must be paid to the impact of different soils and climatic
30
conditions' (p.5). These are not elaborated further, and certainly
not required for safety assessment recommended in the Report.
The range of tests which are actually carried out, as exemplified by
WHO's Workshop Report on applying the principle of substantial
equivalence, is not sufficiently discerning to pick out unintended
effects. Unless there are gross morphological or phenotypic changes,
there is no need to look for them. And even when there are gross
abnormalities, the product can still be assessed to be 'substantially
equivalent'. One paper presented in the WHO workshop reports,
'Field trials on the transgenic lines used in these studies showed
marked deformities in shoot morphology and poor tuber yield in
volving a low number of small, malformed tubers during field tri
als .... These changes were attributed to somaclonal variation dur
ing the tissue culture phase of transformation .... Despite these
marked morphological abnormalities, virtually no changes in tu
ber quality attributes were detected...' (Conner, 1995, p.30). So much
for the discerning power of the tests carried out.
There were no metabolic profiles done by routine techniques such
as High Pressure Liquid Chromatography (HPLC), nor two-dimen
sional gel electrophoresis to scan for unintended expression of genes
- again, another routine technique. The compositional analyses
reported are limited to uninformative amino-acid profiles, or to
known components present at levels greater than 0.1%, or 0.01% at
best. And, as mentioned earlier, the arbitrariness of the compara
tor will already hide any changes due to the transferred gene(s) per
se, which should alert researchers to unintended effects. Instead,
the tests are aimed specifically at intended effects only, and if any
thing, to conceal secondary, unintended effects as much as possi
ble.
The hazard of unintended effects is already well attested to by the
US epidemic of eosinophilia-myalgia syndrome in 1990, resulting
in more than 1,500 affected and 37 deaths, which is linked to the
consumption of L-tryptophan produced by a geneticallymodifed
■ /oo
strain of Bacillus ann/loliquefaciens (Mayeno and Glich, 1994). Sev
eral trace contaminants identified on HPLC have been implicated
in pathogenesis.
A metabolite, methylglyoxal, was found to accumulate at toxic,
mutagenic levels in yeasts engineered with multiple copies of one
of several yeast glycolytic enzymes to increase the rate of fermen
tation (Inose and Murata, 1995). Recently, tobacco plants geneti
cally engineered to produce the gamma-linoleic acid, also unex
pectedly produced octodecatetraenoic acid, a substance previously
unknown in natural tobacco plants (Reddy and Thomas, 1996). In
the absence of a metabolic profile on the product, unintended toxic
metabolites might easily have escaped notice in the safety assess
ment.
It is equally important to check for unintended gene products be
ing produced, which will not be revealed by routine amino-acid
analyses of total lysates, as is done by Calgene for canola meal
(Redenbaugh et al., 1995). A minimum requirement should be a
two-dimensional gel electrophoretogram of the total proteins (Ho,
1996). Even then, minor modifications in a proportion of the pro
teins may not be detectable, but which may change the properties
of the proteins involved. For example, a proportion of the
recombinant porcine and bovine somatotropins synthesized in E.
coli were found to contain the abnormal amino acid e-N-acetyllysine
in place of the normal lysine, only when reversed-phase HPLC
analyses were carried out (Voland et al., 1994).
Key questions on the allergenic potential of transgenic foods are
raised by the recent identification of a brazil-nut allergen in soya
bean genetically engineered with a brazil-nut gene (Nordlee et al.,
1996). It is possible to test for known allergens, as in the case of the
brazil-nut soya bean, but not for allergenicity to proteins completely
new to the foods involved, as acknowledged in the FAO/WHO
Report (p.14). It is significant that allergenicity in plants is thought
to be linked to proteins involved in defence against pests and dis
32
eases (Franck and Keller, 1995). Therefore, transgenic plants engi
neered for resistance to diseases and pests may have a higher aller
genic potential than the unmodified plants. One major novel pro
tein is the insecticide produced by the gene from Bacillus
thuringiensis (Bt), now incorporated into a range of transgenic crop
plants, which had never contained it before. Nevertheless, the pro
ducers were able to claim substantial equivalence by pointing to
its 'comparability' (not identity!) 'to one of the proteins contained
in the commercial microbial formulations that have been used com
mercially since 1988' (Fuchs et al., 1995, p.66).
One important characteristic of an allergen is that it resists diges
tion in the stomach (gastric digestion). According to a recent pub
lication (Astwood et al., 1996), known allergens were stable for 60
minutes, whereas non-allergens were fully digested within 15 sec
onds. While one study claimed that the Bt protein was readily
digestible (Fuchs et al., 1995), another report showed that it failed
to be completely digested under gastric conditions after two hours
(Noteborn and Kuiper, 1995). In both cases, we are assured that
the protein is safe. In view of the recent discoveries that predators
eating pests which have ingested the Bt toxin in transgenic crop
plants are also harmed (Bigler and Keller, 1997; Hawkes, 1997), it is
irresponsible to assume that the toxin is safe for human beings.
We accept that no safety assessment system is foolproof. A case in
point is the rigorous testing that goes on with pharmacological
products. It is estimated that despite such rigorous testing, 3% of
the products approved for market turn out to have such harmful
effects that they have to be withdrawn, while an additional 10%
have sufficiently harmful side-effects that limited use has to be rec
ommended (Suurkula, 1997). This underlines the importance of
segregation, clear labelling and postmarket monitoring of the health
and other impacts of genetically engineered foods. Labelling is a
matter of traceability and should be a scientific requirement, not
only a consumer option.
33
6.7 The spread of antibiotic-resistance marker genes by hori
zontal gene transfer is downplayed, by ignoring existing scien
tific evidence
Antibiotic-resistance marker genes are not mentioned in the FAO/
WHO Report until p. 15, under Section 6.2, 'Gene transfer from
genetically modified plants', where it is stated that '[tjheir contin
ued use in plants remains critical to the production of genetically
modified plants. The Consultation therefore focused on these par
ticular marker genes.' However, all it did was support the conclu
sions of a previous, 1993 Workshop 'that 'there is no recorded evi
dence for the transfer of genes from plants to microorganisms in
the gut' and that there are no authenticated reports of such bacte
rial transformation in the environment of the human
gastrointestinal tract.'6 These conclusions are not based on actual
experiments that have been done to ascertain if these transfers oc
cur. It is a case of interpreting 'the absence of evidence' as 'evi
dence of absence'.
We are told that the first conclusion was 'based on the judgement
that transfer of antibiotic resistance would be unlikely to occur given
the complexity of steps required for gene transfer, expression, and
impacts on antibiotic efficacy'. The steps are listed, the first of which
is the most crucial, 'the plant DNA would have to be released from
the plant tissue/cells and survive in the presence of the hostile
environment of the GI tract, including exposure to gastric acid and
nucleases' (p.16). But that is untrue.
In the course of digestion, plant DNA zuill be released from the
plant cells, and, there is already evidence that large fragments of
viral DNA can survive digestion in the gastrointestinal tract of mice
(Schubbert el al., 1994). So, it is possible that vector DNA, which
carries the antibiotic-resistance marker genes may also resist di
gestion. The question is whether bacteria in the gut can be trans
formed by the DNA, and there is an urgent need for experiments
to be done to answer this question, in view of the wealth of new
34
evidence, since 1993, on the ease with which transformation occurs
in all other environments (see below). Most of the old assump
tions supporting the previous judgement that transfer is unlikely
may be superseded by the new findings.
Because gene-transfer vectors are already extensively modified with sequence homologies to a wide range of species, and to resist
restriction - they may successfully integrate into many bacterial
genomes. It is practically impossible to design vectors that pre
vent horizontal transfer. Furthermore, as sequence homology is
not required for integration into chromosomes or plasmids, ho
mology only makes it more likely to occur. The assumption that
antibiotic-resistance marker genes under plant promoters 'would
not be expressed in a microorganism' (p.16) is dangerous, as so
few bacterial promoters are characterized. While some antibiotic
resistance marker genes are placed under bacterial promoters, as
in the Ciba-Ceigy transgenic maize, there are special mobile ge
netic elements in microorganisms, called integrons, which carry
an enzyme catalyzing the integration of antibiotic-resistance genes
into specific sites where the integrated genes are then provided
with ready-made promoters for expression (Collis et al., 1993). The
Report also fails to take account of the ease with which recombina
tion can occur following horizontal gene transfer, whereby any
missing promoter for the gene(s) may be regained.
Horizontal gene transfer has been demonstrated between bacteria
in the gut of animals as well as human beings since the 1970s
(Anderson, 1975; Freter, 1986; Doucet-Populaire, 1992). For this
reason, gene transfer from genetically modified microorganisms
must definitely be considered in the safety assessment of geneti
cally modified microorganisms, as appears to be recommended by
Section 6.3 of the Report, 'Gene transfer from genetically modified
microorganisms' (pp.17-18). It is stated that '[t]he Consultation
affirmed the recommendation from the 1990 FAO/WHO joint con
sultation ... regarding genetically modified microorganism includ
ing: 1) that vectors should be modified so as to minimize the likeli
35
hood of transfer to other microbes; and 2) selectable marker genes
that encode resistance to clinically useful antibiotics should not be
used in microbes intended to be present as living organisms in food'
(p.18).
However, as stated above, artificial vectors are already extensively
modified; and as modified vectors are often unstable (Old and Prim
rose, 1996), they may be much more prone to mobilize and to re
combine (Allison, 1997; Ho, 1997a; Ho et al., 1997). An additional
problem of antibiotic resistance is that of cross-resistance. For ex
ample, resistance to kanamycin may be accompanied by resistance
to new-generation aminoglycoside antibiotics such as tobramycin
and amikacin (Conner, 1995; Smirnov et al., 1994).
The Report states that '[t]he Consultation was not aware of any
reports of genes from animal, plant or microbial origin into
epithelial cells, except for infectious agents, such as viral DNA.'
But there is already evidence that viral DNA can enter the blood
stream and many kinds of cells in mice.9 Again, vector DNA is
modified viral DNA in many cases, and in the absence of results
from actual experiments carried out to investigate this possibility,
it is not legitimate to conclude that DNA cannot enter epithelial
cells, or the bloodstream and from there, gain access to other cells.
One major immediate danger in this regard is the genetically engi
neered baculoviruses developed as insecticides, which are also si
multaneously developed as vectors for human somatic gene
therapy (see Section 4) which the Report has not even mentioned.
6.8 There is no consideration of unintended gene transfers in
the general environment
The Report has avoided any discussion of horizontal gene transfer
to microbes and other organisms in the general environment, for
which substantial evidence has emerged within the past three to
four years. But there is still no explicit requirement to monitor
such horizontal gene transfers during field releases. It is a blatant
36
omission in view of already existing evidence that transgenic plants
can transfer transgenes and marker genes horizontally to microbes
in the soil (Schluter et al., 1995; Hoffman et al., 1994). Also, reviews
of recent findings by many authors (dealt with in detail in Section
7.5) show that there is essentially no barrier to gene transfer between
microorganisms. The microbes in the environment, in turn, serve as
a gene transfer highway and reservoir for multiplication and re
combination, from which the genes can spread to practically all
other species. Particularly significant are new findings indicating
that genetically 'crippled' microorganisms can survive, or go dor
mant and reappear, after having acquired genes horizontally from
some species in the environment to enable them to grow and mul
tiply; that naked DNA can survive for long periods in all environ
ments and retain their ability to transform; that transformation fre
quencies are high in all environments.
These findings have large implications for the safety of the releases
from contained use, which is itself urgently in need of a full reas
sessment (Ho, 1997b). It is significant that the Norwegian govern
ment banned the imports of two rabies vaccines and four transgenic
plants containing antibiotic-resistance marker genes in September
1997, in recognition of the hazards arising from horizontal gene transfer
and recombination.'0
On account of the possibilities of horizontal gene transfer, it is paramount
that no organism containing antibiotic-resistance marker genes, and in
particular, unknown, uncharacterized foreign gene sequences, should be
considered for release.
37
Chapter 7
Failure to Take Existing Scientific Evidence
into Account
Genetic engineering biotechnology is a rapidly moving area.
Many key discoveries have only been made within the past three
to four years, as reviewed in detail elsewhere (Ho, 1997a; Ho et al.,
1997), which have large implications for the safety of genetically
modified foods. The totality of existing scientific findings leads us
to conclude that an inadequately researched and inherently dan
gerous technology has been pushed prematurely to commerciali
zation. We must emphasize that these indications of hazards have
emerged from a non-exhaustive search of limited databases, and
despite the paucity of specifically targeted research. Relevant data
may be missing in some instances simply because the experiments
or investigations have not been done. It is unacceptable for the
Report to interpret 'the absence of evidence' as 'evidence of ab
sence'. Yet, the Report has registered neither the substantial body
of existing scientific findings, nor the hazards indicated by these
findings.
7.1
The instability of transgenes and transgenic lines
Transgene instability is now a recognized problem in both farm
animals and plants (see Colman, 1996; Lee et al., 1995; Ho, 1996;
Steinbrecher, 1997). In transgenic tobacco, 64 to 92% of the first
generation of transgenic plants become unstable. Similarly, the fre
quency of transgene loss in Arabidopsis ranges between 50 and 90%.
Instability arises both during production of germ cells and in cell
division during plant growth. The commonest cause of transgene
instability is gene silencing (see Finnegan and McElroy, 1994; Ho,
39
1996,1997a, Chapters 8 and 9) - the inability of the introduced gene
to become expressed - due to chemical modification (methylation)
of the DNA. Other causes are DNA rearrangements and excision
of the transgene. The stability of the transgenic line may also be
compromised by somaclonal variation - variation arising during
plant cell culture after transformation (Cooking, 1989) - which has
been known for a long time. Instability may also be due to the
tendency of the insert towards secondary mobilization (see Ho,
1997a, Chapter 9).
Instability', such as secondary mobilization, may be triggered by
extreme environmental conditions, such as heat and drought. For
this reason, transgenic plants must be tested for stability under these
conditions before they are approved for market. All these factors
compromise the quality of the product. Not only do they have
socioeconomic impacts for farmers, but they have large implica
tions for food security and food safety, since they increase the po
tential for unintended effects as well as secondary gene transfers.
7.2 The prevalence and scope of horizontal gene transfer in all
environments, including the gastrointestinal tract
The full scope of horizontal gene transfer is such that any gene
released in any species has a finite probability of being transferred
to many other species of both eukaryotes and prokaryotes
(Stephenson and Warnes, 1995). Direct transfer has been demon
strated from higher plants to bacteria, and to fungi (Schluter et al.,
1996; Hoffman et al., 1994), and from bacteria to plants. The Ti (Tu
mour-inducing) plasmid of the soil bacterium, Agrobacterium,
widely used in modified versions as vectors for making transgenic
crop plants, actually mediates conjugation between Agrobacterium
and plant cells (Kado, 1993). This is why the secondary mobility of
such vectors in transgenic crop plants cannot be ruled out, and
should have been rigorously monitored. It is well known that
helper-functions supplied by endogenous elements - which are
ubiquitous in genomes - can mobilize elements that do not have
40
their own enzymes for mobility. Indirect evidence also exists of
two-way transfers between bacteria and viruses and the animal
kingdom. Most of all, the bacteria and viruses in all environments
act as a gene transfer highway and reservoir, for multiplying and
recombining genes and from which the genes can spread to all spe
cies.
Another means of horizontal gene transfer is via insects that visit
plants. Aphids, bees and butterflies, for example, will spread in
fectious viruses that arise in transgenic viral-resistant plants from
recombination (see Section 4 above).
All the means available to microorganisms - transformation,
transduction and conjugation - are utilized. New discoveries in
dicate that the frequencies of horizontal gene transfers in all envi
ronments are much higher than previously thought. It has been
demonstrated in the marine environment (Frischer et al., 1994;
Lebaron et al., 1994), in the freshwater environment (Ripp et al.,
1994) and in the soil (Neilson et al., 1994). Horizontal gene transfer
occurs preferentially in interfaces between air and water and in
the sediment, and especially under nutrient depletion conditions
(Goodman et al., 1994). Transfer (of multiple antibiotic resistance)
has even been demonstrated in wastewater treatment ponds
(Mezrioui and Echab, 1995).
Transformation (by uptake of naked DNA) in the environment
(Lorenz and Wackernagel, 1994) is extremely widespread. Both
chromosomal and plasmid DNA are able to transform bacteria.
Cross-species, cross-genera and even cross-order transfers have
been observed with chromosomal DNA, while plasmid DNA has
effected cross-kingdom transformations. Similarly, transduction
may be substantial in aquatic environments (Bergh et al., 1989),
while conjugation is essentially promiscuous when it is realized
that retro-transfer from recipient to donor can also occur, and that
conjugative transposons can jump between plasmids and chromo
somes (Clewell, 1993).
41
As mentioned in Section 6.7 above, horizontal gene transfer be
tween bacteria has been documented in the gastrointestinal tract
of animals as well as human beings.
7.3
DNA is not readily degraded in the environment
Recent findings show that DNA can persist for days, weeks and
even months in the environment, especially when adsorbed to solid
particles in the soil or in aquatic sediments, where they retain their
transforming power (Jager and Tappeser, 1995; Lorenz and
Wackernagel, 1994). This is contrary to previous assumptions that
DNA-degrading enzymes (DNases) in the environment will rap
idly break down DNA. Thus, DNA released from dead plant cells
or dead microorganisms may retain the ability to transform other
organisms. Transgenic plant exudates, and debris ploughed back
into the soil, are very likely to release DNA for transforming soil
bacteria and other microbes. In the aquatic environment, dead cells
from transgenic fish and other organisms will release DNA capa
ble of transforming bacteria and viruses which are abundant in the
aquatic environment. Transgenic domesticated animals or 'pharm'
animals will pass dead cells in their faeces in the farmyard, which
will release DNA for transforming soil microbes.
7.4 Transgenic bacteria, even those that are 'biologically crip
pled', may survive and multiply in the environment
This topic has been reviewed recently (Jager and Tappeser, 1995).
Individual strains of genetically manipulated microorganisms
(GMMs) can survive and outcompete wild-type strains. Even when
they seem to disappear after release, GMMs can often go dormant
and reappear. A laboratory strain of E. coli K12, introduced into
the sewage, went dormant and undetectable for 12 days before re
appearing, having acquired a new plasmid for multidrug resist
ance that enabled it to compete with naturally occurring bacteria
(Tschape, 1994).
42
7.5 Horizontal gene transfer is now known to be responsible
for spreading antibiotic resistance and virulence among patho
gens
Non-pathogenic GMMs could evolve into pathogenic ones by hori
zontal gene transfer. E. coli 0157 is one such example; its Shigella
like toxins have probably been acquired by horizontal gene trans
fer from Shigella." There have been many publications document
ing the spread of antibiotic resistance by horizontal gene transfer
and recombination (reviewed by Ho and Tappeser, 1997; Ho, 1997a,
Chapter 10). The first evidence involves resistance genes acquir
ing neomycin-kanamycin resistance (Trieu-Cuot el al., 1985). Since
then, horizontal transfer of many other antibiotic-resistance genes
has been found, including that of tetracycline resistance and even
chromosomally encoded penicillin resistance (Ambilecuevas and
Chicurel, 1993; Bootsma et al., 1996; Coffey et al., 1995; Kell et al.,
1993; Manavathus et al., 1988; Roberts, 1989; Sougakoff et al., 1987;
Speer et al., 1992; Spratt, 1988,1994).
The same mechanisms for horizontal gene transfer have been shown
to be responsible for the emergence of virulence among old and
new pathogens since the mid-1980s, including Streptococcus pyogenes
(toxic-shock syndrome) (Kehoe et al., 1996), group A streptococci
isolated from a cluster of cases in the 1993 epidemic in Tayside,
Scotland (Upton et al., 1996), Vibrio cholerae (Bik et al., 1995),
Mycoplasma genitalium (Reddy et al., 1995). A fuller report on this
topic is in preparation (Ho et al., 1997).
The gravity of these findings should be appreciated in the light of
the current crisis in public health worldwide, due to the emergence
of old and new pathogens which are resistant to multiple antibiot
ics, as detailed in the 1996 WHO Report. A fuller discussion of this
topic has been presented elsewhere (Ho, 1997a, Chapter 10).
43
7.6
The ability of viral DNA to survive digestion in the gut
This has been demonstrated by feeding viral DNA to mice. Large
fragments survived digestion and were passed out with the faeces.
At the same time, viral DNA was found in the bloodstream and in
many kinds of cells in the body.12
7.7 The ability of recombinant vectors to invade mammalian
cells
As mentioned in Section 7.6 above, DNA can easily gain access
into cells. Studies made since the 1970s have documented the abil
ity of bacterial plasmids carrying a mammalian virus (SV40) to in
fect cultured mammalian cells, which then proceeded to synthe
size the virus. Similarly, bacterial viruses or baculoviruses can also
be taken up by mammalian cells (Heitman and Lopes-Pila, 1994).
The baculovirus is so effectively taken up by mammalian cells that,
as mentioned earlier, it is now being developed as a gene transfer
vector for human gene replacement therapy (Hofmann et al., 1995;
Sandig et al., 1996), at the same time that it is being engineered for
insecticidal purposes (Jehle, 1997).
7.8 Recombination between viral transgenes and viruses gen
erates superinfectious viruses
This ability has been known since 1994. Plants engineered with
one of several viral genes or other sequences can acquire resistance
to the virus, although the mechanisms are still poorly understood
(Sela, 1996). It is now sufficiently well established that viral
transgenes can recombine with other viruses to generate new vi
ruses (Anderson et al., 1992; Greene and Allison, 1994; Palukaitis
and Roossinck, 1996; Allison, 1997) for the US Department of Agri
culture to consider new restrictions on viral-resistant transgenic
plants (Kleiner, 1997). Transgenic plants contain the viral gene in
all their cells all the time, thus greatly increasing the probability of
recombination.
44
A more general hazard comes from all transgenic organisms, as
different viral sequences are incorporated into a range of gene trans
fer vectors. The cauliflower mosaic virus promoter, for example, is
routinely used in vectors for making transgenic plants (Cummins,
1994). These have similar potential to generate new viruses either
in the environment or when ingested by human beings and other
animals. There have been no experiments carried out to date to
investigate this possibility.
7.9
Antibiotics promote horizontal gene transfer
Recent findings show that the presence of antibiotics greatly in
creases the frequency of horizontal gene transfer, from one to four
orders of magnitude (Davies, 1994; Mazodier and Davies, 1991;
Sandaa and Enger, 1994; Torres ef al., 1991). Antibiotics are already
widely present in the environment, from intensive farming and
hospital effluents. The potential for spreading antibiotic resistance
by horizontal gene transfer may be therefore, much, much higher
than previously thought. There is an urgent need for appropriate moni
toring of horizontal gene transfer in limited field releases before further
products are approved.
45
Chapter 8
A 'Safety Assessment' Designed to
Expedite Product Approval with Little or
No Real Regard for Safety
Our detailed analysis of the Report leads us to conclude the fol
lowing:
•
it makes biased, partisan claims in favour of genetic engineer
ing biotechnology;
•
it wilfully excludes known hazards from safety assessment;
•
it ignores existing scientific evidence pointing to the hazards;
•
it presents a 'safety assessment' based on an arbitrary and un
scientific 'principle of substantial equivalence' that effectively
allows the producer to pass any and every product with im
punity and with little or no regard for all aspects of safety.
A recent, leaked document (Penman, 1997) indicates that
EuropaBio, representing the interests of the industry, is advised by
the public relations company Burson Marsteller - whose clients
include Babcock and Wilcox during the Three Mile Island nuclear
crisis in the US in 1979, and Union Carbide after the Bhopal disas
ter in India, which killed up to 15,000 people - to 'stay quiet on
risks of gene-altered foods' as 'it cannot hope to win the arguments
over the risks posed.' We agree.
So why does a Report on food safety produced by such authorita
tive international agencies like the WHO and FAO not take any of
47
the risks seriously? The answer is in the same document leaked by
Burson Marsteller, which suggests that 'the best way of eliciting a
favourable consumer response to new products must be to use regu
lators and food producers to reassure the public.'
The predominant philosophy behind current regulation can be
summarized by the 'No need - don't look - don't see' futile cycle
(Fig. 1). Starting from the 'no need, don't look' basis - the assump
tion that genetic engineering is no different from conventional
breeding, so it is not really necessary' to provide special oversight
one progresses to the 'don't look, don't see' safety assessment em
bodied in the principle of 'substantial equivalence', before ending
up in a 'don't see, no need' reinforcement of the position with which
one began.
As can be seen, this forms a self-reinforcing cycle, a motor for ef
fectively passing with impunity any and every genetically engi
neered product to the public that the industry so wish. We repeat,
the industry have been handed carte blanche to do as they please
for maximum profitability, with the regulatory body acting to al
lay legitimate public fears and opposition.
Figure 1. The futile cycle of food safety regulation
recommended by the Report
48
Chapter 9
Recommendations
In view of the gross inadequacies in food safety regulation and
the existing scientific evidence pointing to serious hazards, we rec
ommend the following minimum measures to safeguard the health
of consumers and to protect biodiversity. A moratorium on fur
ther releases must be imposed until these measures are imple
mented.
a.
No food crops are to be engineered for producing pharma
ceuticals and industrial chemicals, as the engineered crops
could be mistaken for food, or cross-pollinate with non-engineered food crops. The onus must be on the producer to prove
that any plant genetically engineered is not a food crop.
b.
All projects involving genetic manipulation of the baculovirus
for insecticidal purposes should be discontinued, as this vi
rus is being used in human gene therapy and invades human
liver cells readily.
c.
Complete characterization of inserted gene sequence(s) of the
genetically engineered organism (GEO) must be provided in
the application for market approval. This should include any
antibiotic-resistance marker gene(s), promoter(s) and
enhancer(s) and their effects on the expression of neighbour
ing genes. The presence of mobile genetic elements and other
proviral sequences in the host genome, likely to contribute to
secondary mobility of inserts, must also be stated.
49
d.
No GEOs with uncharacterized foreign gene inserts are to be
considered for release. No parts of such GEOs, nor of animals
from failed genetic engineering experiments or xenotransplant
animals are to be used as human food or animal feed.
e.
No GEOs containing antibiotic-resistance genes are to be con
sidered for release or to be used as human food or animal
feed.
f.
A detailed record of the stability of the GEO over at least five
successive generations under field conditions (including
drought and heat) is a precondition for market approval.
('Field conditions' does not mean open field conditions.) This
must be supported by appropriate data indicating the stabil
ity of the insert as well as the level of gene expression under
different conditions in successive generations.
g.
Data on the frequency of unintended gene transfers, includ
ing horizontal gene transfer from the GEO under field condi
tions, must be included in the application for market ap
proval.
h.
Data on the frequency of horizontal gene transfer from the
GEO to gut bacteria must be included in applications for mar
ket approval.
i.
Data on the ability of transgenes and marker genes in the GEO
to invade mammalian cells must be included in applications
for market approval.
j.
A specified set of tests must be carried out to establish 'sub
stantial equivalence', which are sufficiently discerning to re
veal unintended as well as intended effects. The comparator
.must be the unmodified recipient organism itself, and results
/.of 'repeated tests must be provided to support the stability of
; the characteristics over at least five successive generations.
.
’i * 1
50/.
■"
•>.%'.
’
’■
k.
Safety assessment must include the GEO's potential to gener
ate pathogens through genetic recombination.
1.
Safety assessment must include pesticide residues where they
are integral components of the product, as in herbicide-resist
ant transgenic plants.
m.
Product segregation, labelling and postmarket monitoring are
non-negotiable conditions for market approval.
- IDO
U8673
Endnotes
1
Personal communication, Pierre Hochuli, Monsanto Europe, April
1997.
2
Nature Biotechnology 15, 701,1997.
3
Despite what is claimed in the title of the paper, the actual observed
frequencies were high, from which the authors calculated an extremely
low frequency' through various unsubstantiated assumptions concern
ing 'natural' conditions.
4
The work of this group of scientists was reported recently in the New
Scientist, 4 January 1997, p.24.
5
Reported in Manitoba Co-Operator 24/4/97; also The Rain's Horn, No.
147, April 1997.
6
Applications of the Principles of Substantial Equivalence to the Safety Evalu
ation of Foods or Food Components from Plants Derived by Modern
Biotechnology, Report of a WHO Workshop, SHO/FNU/FOS/95.1, p.7.
7
See note 6.
8
Health aspects of marker genes in genetically modified plants. Report of a
WHO Workshop, WHO/FNU/FOS.93.6,1993.
9
See the New Scientist, 4 January 1997, p.24.
10 Norwegian decision to prohibit deliberate releases of six genetically
modified products approved for marketing in the EU. Third World
Network Briefing Paper, circulated in UN Meeting of the Ad Hoc
Working Group on Biosafety, 13-17 October 1997.
11
Professor Hugh Pennington, BBC Radio 4 Today Programme, Febru
ary 1997, confirmed by personal communication.
12 See the New Scientist, 4 January 1997, p.24.
52
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ABOUT THE AUTHORS OF THIS PAPER
Dr Mae-Wan Ho is a well-known arid respected
British scientist, Reader in Biology at the Open Uni
versity, UK, and a Fellow of the US National Genetics
Foundation. Since 1994 she has been scientific
adviser to the Third World Network and other public
interest organizations on genetic engineering bio
technology and biosafety. She has debated the issues
at the United Nations, the World Bank, the European
ParUament, and many conferences all over the world.
She is also a prolific author of over 150 works in
several disciplines, a popular public lecturer and a
frequent contributor to radio and TV in the UK and
elsewhere.
Dr Ricarda A Steinbrecher has a PhD in human
molecular genetics and is a scientific consultant for a
number of public interest organizations.
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