73. The risks to human
health of GM crops when eaten are considered in paragraphs 109 to
116. It has been argued that some modifications may, while in the
field, pose risks to humans or unintended harm to other animals.
This may be due, for example, to an increase in the allergenicity
of pollen. These issues are considered and tested during trials
and assessed in the risk assessment. Our comments relating to
risk assessment must be considered as applying to this aspect
of GM crops as much as to environmental issues.
74. The risk to the environment of GMOs is much
more difficult to estimate than the effect on human health. Many
modifications, such as slower ripening, are likely to have no
effect at all, good or bad. The assessment of risk is also complex,
for the intensification of agriculture has increased food supply
and quality, but at a cost to the environment through chemical
weed and pest control, the use of fertilisers, a reduction in
the number of varieties of many crop plants in cultivation (Professor
Williamson, Q 490) and a reduction in wildlife habitats. The risks
of a GM crop must not thus be considered in isolation, but compared
to the risks of current agricultural practice and an assessment
of best practice. The risks posed by GMOs are, however, intangible
and yet to be demonstrated (Professor Burke, former chairman of
the advisory committee on novel foods and processes (ACNFP) and
Professor Beringer, chairman of the advisory committee on releases
into the environment (ACRE), Q 36). Many of the claims which have
to date reached the headlines have been misleading.
Harm to the environment or otherwise by GM crops has yet to be
demonstrated experimentally, but many of our witnesses believed
that the following issues need to be addressed.
MODIFIED GENES BE TRANSFERRED TO OTHER ORGANISMS?
75. It is certain that
gene transfer between micro-organisms takes place, but this has
to be set in context (Professor James and Dr Chesson, QQ 641-3).
It only causes a problem when the transfer is to a pathogenic
organism or if the resultant organism is a pathogen. The transfer
of genes from micro to higher organisms (such as plants) occurs
only with very few bacteria such as Agrobacterium, used
in one type of modification process.
Transfer from plants to bacteria is extremely improbable.
The possibility has however led to particular concerns about furthering
the spread of antibiotic resistance through the use of antibiotic-resistant
marker genes (Gene Watch, p 335). Recently an ampicillin tolerance
gene was included within a transgenic maize. It was a bacterial
gene, complete with a bacterial promoter.
ACNFP was concerned at the remote but finite possibility that
the gene could be transferred to bacteria within the rumen of
a cow which ate the maize as feed and concluded that it therefore
constituted a hazard (Professor Burke, Q 35, also Professor Bainbridge
QQ 693-4). An
eventual decision allowing the use of this maize within the European
Community was based on the presumption that the gene could be
transferred, and weighed the consequences against the existing
prevalence of ampicillin resistance within bacteria. Antibiotic
resistant marker genes are not now used in new products (Dr Chesson,
Q 669). We consider that ACNFP was correct to proceed with
extreme caution where the possibility of furthering antibiotic
resistance was present.
In view of the fact that alternatives are now available, antibiotic-resistant
marker genes should be phased out as swiftly as possible.
76. There is evidence to show that DNA from any
food can survive in a human's gut and even be absorbed by gut
cells (Professor James and Dr Chesson, Q 639). The incorporation
of such DNA into the genetic material of the cell must however
be an extremely rare event (Q 640).
We discuss this issue in paragraph 109).
77. Gene transfer is dependent on sexual compatibility
and not all plants are compatible with each other, hence the limitations
of conventional breeding. In the agricultural environment, genes
may be transferred to similar crop plants in adjacent fields.
This is a hazard already faced by farmers growing similar crops
at close quarters. Under normal circumstances, this would only
be a hazard if the affected farmer retained seed for replanting
in later years,
but with those plants where the seed is the crop this would be
a problem within the same year as seed on adjacent crops might
inherit the transgenes and so alter the crop's characteristics.
As modifications become more varied this may have serious implications
for what crops can be grown next to each other and for the retention
of seed for replanting (see also paragraphs 105-106). Where plant-produced
pharmaceuticals are concerned, we recommend either that these
are grown indoors or that out-crossing should be made biologically
impossible, by, for example, ensuring male sterility.
78. The Soil Association
saw the introduction of genetically modified plants into United
Kingdom agriculture as the "most serious threat ever to the
objectives and progress of the organic farming movement in developing
and introducing viable systems-based approaches to agriculture"
(p 390). The European Commission has proposed that products containing
or derived from GMOs should not be allowed to be used for foods
sold as organic. Professor Williamson however considered the organic
movement's rejection of genetic modification to be unfortunate,
as GM was compatible with sustainable lower input farming (Q 499).
This view was reinforced by our visit to the John Innes Centre,
when staff suggested and demonstrated that current GM crops were
designed for more sustainable agriculture with less reliance on
chemicals. To take the example of pest resistant crops, either
a pesticide can be engineered into the crops (as with those using
Bt) or the crop can be modified to attract insects which prey
on the pest. The latter method seems compatible with the principles
of organic farming. Risk management procedures need to be employed
to minimise transfer of the genes into adjacent crops, particularly
those owned by other farmers. This is of particular importance
where organic crops are grown, as drift of the transgenes into
the seeds might result in harm to the property of the organic
farmer. It should be a responsibility of farmers to prevent out-crossing
(see paragraphs 105-107). We consider that GM technology may offer
much to organic systems, for example through reduced inputs.
79. If there are weeds which are sexually compatible
with a herbicide tolerant crop (such as weed beet with sugar beet),
the out-crossing of transgenes may cause significant harm to the
agricultural environment (SNCAs, p 320), but only if other methods
of control, such as selective herbicides, are not available (Zeneca,
Q 89). Transfer of such genes into wild relatives in the natural
environment could result in irreversible effects on natural vegetation
(Dr von Schomberg, pp 401-2). There will however not generally
be selection pressure to retain the transgene and it should in
time disappear. The transfer of herbicide resistance outside
agriculture is unimportant in areas where herbicides are not generally
used (for example field margins or woodland), but could cause
control problems in areas dependent on chemical control, such
as road-side verges, railway tracks or runways.
80. A herbicide-tolerant crop may also establish
itself as a weed and cause harm to the ecology and its processes
within any ecosystem in which it stabilises (Royal Society for
the Protection of Birds (RSPB), pp 384-5). Professor Williamson
suggested that this cannot be predicted as there is some uncertainty
as to what makes plants weedy. He suggested that the characteristics
that would be expected to indicate invasiveness could not be expressed
quantitatively (Q 505). In the agricultural environment, should
a herbicide tolerant crop survive into the next growing season
(described as a "volunteer"), it will pose weed problems
for the new crop and may, if compatible, breed with it. This would
increase the rapidity of multiple tolerances developing.
81. If varieties of the same crop are modified
to express tolerance to a range of herbicides, gene-stacking may
eventually occur (Iceland, p 64). This is where a plant develops
resistance to a number of systemic herbicides commonly used in
agriculture and effectively becomes less controllable. Zeneca
noted that this is a longstanding agricultural issue (QQ 89-90)
which requires that new agricultural chemicals be developed every
82. If a crop plant is
modified so that it is able to be grown in new environments (geographical
locations, altitudes, soil types, conditions of excess water or
drought, or even different seasonal cropping) it may become a
weed or pose risks to the environment into which it is newly introduced
(Professor Beringer, Q 25; Professor Williamson, Q 505). Such
a risk would need to be set against the benefit of the crop's
introduction. Land on which wildlife depends, previously not
used for cropping, may be brought under cultivation.
83. The development of pest resistance has so
far focused on genes which produce the toxins derived from the
bacterium Bacillus thuringiensis (Bt).
These toxins are effective against a range of insects, particularly
certain lepidoptera, but are harmless to plants and to humans.
They are used in a wide range of pesticides and the bacterium
itself is used for pest control in organic systems. Pesticides
are normally applied to crops at specific times during their growth
and normally dissipate and are rapidly degraded in the soil. Conversely,
plants which express pesticides are likely to do so uniformly,
throughout the life of the plant, which may result in a greater
likelihood of insects developing resistance to the effects of
the toxin (Greenpeace Q116). GM crops may be much more effective
at killing target insects and other susceptible insects and so
deprive of food higher organisms which prey on them, such as birds
(RSPB, p 386). On the other hand, the impact of pest resistant
plants may be beneficial due to their selectivity, because the
pest resistance only affects insects which attack the plant, as
opposed to a spray which affects all susceptible insects in the
field. Whether the net effect will be positive or negative has
yet to be resolved.
EC AND US: CONTRASTING
84. Changes in farming practice during the past
30 years have already had a significant impact on wildlife as,
throughout Europe, it is particularly dependent on farmland (RSPB,
pp 386-7). Farmland constitutes 70 per cent. of the United Kingdom's
land area, much more than in the United States.
In addition, the use of agricultural chemicals per acre in Europe
is much higher than in the United States. Due to both of these
factors, sensitivity to the possible impact of genetically modified
organisms on the environment may be much more significant within
Europe than in the United States.
CARTELS AND MONOPOLIES
85. There is concern,
shared by farmers, witnesses and ourselves, that the powers of
a few agro-chemical/seed companies are already very great, and
will become even greater, over the process of producing (developing
and growing) genetically modified crops. United States soybean
producers told us of their anxiety that in the future they would
be growing specialised, value-added GM crops, the profit from
whose added value would accrue predominantly to the companies
rather than to themselves. Additionally, agricultural biodiversity
(the number of varieties of a particular crop in production) may
also be further reduced by consolidation in the industry when
it is already an issue of concern.
In this respect, the Seed Bank at Kew acquires added significance.
It is highly desirable that there should be competition between
a sufficient number of companies on a world-wide basis. The degree
is already much greater than that which obtains in the pharmaceutical
sector and we consider that it should not progress any further.
It is however a competition issue and should be dealt with by
competition law. The multi-national aspect of the agrochemical/seed
sector must not override regulation. Should agrochemical companies
pursue research prohibited in Europe in countries which lack as
stringent a regulatory system, we would deplore such actions.
ONE-USE ONLY CROPS
86. GM crops introduced
commercially in the United States have resulted in a change to
farming practice in that farmers no longer have the right, or
sometimes the ability, to retain seed for replanting the following
year. This is either because the seed company insists on licensing
the right to plant
or because the plant is male sterile, and so produces no seed.
Where the crop is male sterile, this has the environmental advantage
that out-crossing and back-crossing are impossible (NFU, Q 290).
The American Soybean Association, in contrast to the NFU (Q 291),
does not consider this to be a problem as they value the guarantee
that all their seed is first quality and free from disease. They
have chosen to purchase the entirety of their GM seed rather than
follow their tradition of keeping up to two thirds of seed for
replanting the following year. As value added products (such as
altered oil property soya) are introduced, it will be important
for the farmer to be certain of seed quality and origin to ensure
that the desired modification is in fact present in the crop.
This change-over from retention to non-retention of seed is not
as dramatic as it seems, for many of today's agricultural crops
are hybrids which lose their vigour (and hence their yield value)
after the first use. In relation to the developed world, so
long as the farmer's economic prosperity is not unduly affected,
we do not consider either the licensing of the right to plant
or the sale of seeds which will produce sterile crops to be a
problematic development. Both of these approaches should assist
product traceability. In the developing world, however,
many and probably most farmers would view the prospect of having
to buy seeds each year with grave concern.
87. We recognise that
there could be significant potential risks to the environment
associated with the use of genetically modified organisms but
are convinced that the benefits could be substantial in terms
of yield, quality and new products. We agree with Professor Williamson
that this technology is "certainly desirable" (Q 487),
but is only likely to succeed if it gains widespread public acceptance
and trust in its safety. The process of assessing risk is therefore
of crucial importance to the future of the technology.
88. Current risk assessment
procedures for both trial and commercial releases assess solely
the risks of allowing the release to proceed and do not consider
any benefits. Many witnesses recommended that risk assessment
should be replaced by "environmental impact analysis",
which would take environmental benefits into account as well as
risk (Novartis, pp 372-3). (If it is possible to identify environmental
risk, then it must be possible to identify environmental and other
benefits.) "It would be useful, therefore, if both regulators
and consumers were able to balance potential risk against possible
benefit" argued Dr Gliddon (pp 340-1). We consider that
environmental risks and benefits should be assessed at the same
114 Two notable causes célèbres
are those of lacewings which might eat the European cornborer,
poisoned by Bt maize (a secondary effect) and the potato to which
an immune system affecting lectin had been added. Swiss research
has suggested that lacewings, if fed on the larva of cornborers,
(which Bt maize is designed to kill) could also be killed, with
potential effects on the entire ecosystem. ACRE was unhappy with
the research, as, in practice, the lacewing would never gain access
to the cornborer as the cornborer is inside the maize (see Novartis,
pp 377-8). Scots research demonstrated that a lectin known to
affect the immune system retained this characteristic when transferred
into a potato, or mixed with potato. It was not and is not suggested
that this lectin would ever be used in a food, and, were it to
be, it is more than unlikely that ACNFP would approve it (see
Professor James, QQ 637, 644). Back
115 See paragraph There are two main methods for the transfer of genes into plants. The first involves the use of a soil bacterium, Agrobacterium tumifaciens, which infects certain plants. It injects a piece of DNA into the plant cell to attempt to take over the cell's protein manufacturing machinery and so produce a sugar on which the bacterium can feed. This piece of DNA is incorporated into the genome of the infected cell. Scientists use this piece of DNA by effectively hijacking it. Having removed some of the unneeded genes, they are able to insert desired genes into the vacated space. Using Agrobacterium it is possible to modify many dicotyledonous (broad leaf) plants such as potato, rape, tobacco and tomato and the technique has been adapted to work on maize, wheat and rice. The second method involves the use of "biolistics" (the "gene gun") where the desired gene package is coated around finely divided gold particles and literally fired into plant cells. A small percentage of the plant cells is transformed in each case. In either method, one of the genes inserted into the plant will produce a protein that confers tolerance to a chemical that would normally kill the cell, a herbicide for example. When the chemical is administered, only those cells which have been effectively transformed and satisfactorily express the new gene product are not killed and a complete plant may be regenerated from these. (This gene is termed a "marker gene" because it is used to identify the presence of the transgene.) The laboratory modification is only carried out on a suitable sub-set of varieties of the crop. These varieties are then crossed (and back-crossed) using traditional breeding technology in order to put the desired genetic material into choice varieties for agricultural production.
116 Genes in higher organisms tend to include regions of DNA that
do not code for protein (termed introns). Bacteria are not able
to translate these genes, hence expression is almost impossible.
The promoter sequences in higher organisms are also significantly
different from those in prokaryote organisms. Even where transgenes
do not include introns, the probability of transfer of genes from
higher organisms into bacteria remains extremely improbable. Back
117 Novartis, pp 375-6 and Annual Report of the ACNFP, 1996, Appendix
IV, pp 55-62. Back
118 In 1994 ACNFP reported "on the use of antibiotic resistance
markers in genetically modified food organisms". They concluded
that antibiotic resistance markers in foods should be evaluated
on a case by case basis and that the evaluation should include
assessment of the clinical use of the antibiotic, the likelihood
of transfer (and expression) of the gene into gut micro-organisms
and the toxicity of the gene product. Back
119 The events that led ACNFP to advise the United Kingdom competent
authority to oppose the marketing of the maize are fully documented
in the annual reports of the Committee for 1996 and 1997. ACNFP
is however also correct in accepting that once the Commission,
advised by its scientific committees, has decided that this gene
and its product does not pose a risk (as the resistance is already
widespread in the environment) it can no longer justify objections
to products containing this or similar genes. See also the recent
report of the Science and Technology Committee, 7th Report (1997-98):
Resistance to antibiotics and other antimicrobial agents
(HL 81-I). Back
120 See also New Scientist, 31 October 1998 (No 2158), p 44. Back
121 Whether genes can be transferred depends on how closely related
the parents need to be for a successful match and also on the
pollen from the GM variety physically reaching the other plant.
The distance over which pollen can travel is dependent on the
crop and prevailing environmental conditions such as temperature,
wind and insect populations. It is impossible to provide general
figures for pollen viability, but MAFF recommends the following
isolation distances for producing 99 per cent. pure seed: wheat,
barley or oats, 2m or physical barrier; oilseed rape, 200-500m;
sugar beet, 1,000m. A trial of one oilseed rape at the John Innes
Centre found 0.0038 per cent. pollution at 400m, but this is only
one variety in one particular circumstance. Back
122 Currently, for most crops, approximately one third of seed is
123 Mr Rooker announced to us that herbicides will require a separate
approval to be used on GM crops (Q 603). Back
124 Products containing this organism constitute 80 - 90 per cent.
of the microbial pesticides which are purchased and used. It was
first registered in the United States in 1961. Back
125 POST, op. cit., p 12. Back
126 The Ministers were keen to note that not only did farming only
cover 10 per cent. of the United States, but that "natural"
countryside in the United States (for example the national parks,
regarded as wilderness areas) was in completely separate areas
(QQ 622, 634). Back
127 See, for example, Professor Williamson on the traditionally bred
Texas Cytoplasm corn, p 214. Back
128 As a resource for future breeders, so that they are not limited
to varieties currently in production, but have access to the widest
possible gene-pool. Back
129 Furthered both by Monsanto's acquisition of Plant Breeding International,
Cambridge and by the agreement between Novartis and Hoechst during
the course of this enquiry. Back
130 The seed bag for Monsanto's Roundup Ready soybeans in the United
States bears the message "These seeds are covered under U.S.
patent 4,535,060 4,940,835 and 5,352,605. The purchase of these
seed convey no license under said patent to plant these seeds.
A license must first be obtained from Monsanto Company before
these seeds can be used in any way." Back