E. Ann Clark, Plant
Agriculture, University of Guelph(eaclark@uoguelph.ca)
Copyright
1999 E.A.Clark
The goal of today's presentation is to present you with evidence that field crop genetic engineering (GE) is not ready for prime time. Indeed, it is at least arguable that ag biotech may never be ready for real world applications, not due to ill-informed consumer hysteria but because of simple biological reality(1). The list of risks which have somehow escaped the attention of regulators, due to the ineffectiveness of the concept of substantial equivalence, expands daily.
The myth of strong, nearly unanimous support
for GE within the ag science community is just that - a smug and soothing
myth: it does not exist now and never has. However, the strong and almost
wholly one-sided support given to fund industry-driven GE research is and
has been anything but a myth. It is to our advantage as an industry to
face risks forthrightly, instead of dismissing them as "scare tactics".
The advice given by Gordon Conway, President of the Rockefeller Foundation
to the Monsanto Board of Directors (14 July 1999) and subsequently released
by him to the press, was blunt and forceful:
| "Admit that you do not have all the answers...Commit yourselves to prompt, full, and honest sharing of data. This is not the time for a new PR offensive but for a new relationship based on honesty, full disclosure, and a very uncertain shared future." (N.B. emphasis added) |
His raw candor, and the urgency of his warning that continued subterfuge risked bringing down the wrath of the scientific, political and global community on them (Vidal, 1999), reportedly infuriated his host, Bob Shapiro, who had expected that a foundation which had itself invested $100 million in public GE research would be supportive and friendly.
Fortunately for all of us, someone of the stature of Gordon Conway may be able to achieve what lesser mortals have consistently failed to do - focus the attention of Monsanto and the other life science giants on the very real uncertainties and risks of GE technology.
Using Substantial Equivalence to Debilitate the Concept of Risk So, what is all the fuss about? Anyone who has searched for government funding of risk assessment research (nil), or leafed through government GE promotional literature (CFIA, 1997) or perused the contentious AIC "Statement on Biotechnology" could easily conclude that GE posed little or no risk to anyone or anything.
Winfield (personal communication, 1999) noted that roughly $700 million(2) in government money is allocated to GE research in Canada now, but none is specifically earmarked for risk assessment. No targeted federal or provincial research focuses explicitly on assessment of agronomic or environmental risks or on food safety hazards attributable to GE. In the US, a paltry 1% of the USDA budget for biotechnology has been expended in risk assessment research starting in 1992. Why is it that even that allocation had to be imposed by politicians in the 1990 Farm Bill, rather than being undertaken proactively and responsibly by government regulators or the scientific community in general? The virtual absence of meaningful consideration of GE risks means that when Consumer Reports (September 99) states that that there is "no evidence" of harm from GE foods, they speak the literal truth. There is no evidence of harm because the proprietors of GE crops were not required to actually test and provide evidence of food safety (or anything else) as a condition of registration. The absence of evidence (of risk) should not be taken to mean evidence of absence of risk.
Yet this is just what some oft-quoted industry apologists do. They point triumphantly to the 20 or more years of industry-funded research which have accrued in developing the 40+ GE crops approved for Canadian agriculture today, as if "years-in-service" should deftly handle any and all challenges. But twenty years or multiples of twenty years will not help to identify and avoid risks if the research is not designed to address questions of risk in the first place. And indisputably, the questions under study in virtually all government and industry-funded labs to date have been "how to make it work" instead of "what happens when it does work" or better yet "why are we doing this at all?"
Industry proponents are quick to point to the websites of the Canadian Food Inspection Agency(3) and Health Canada(4) as evidence of the due regard accorded both the environment and food safety issues in Canada. Examine them carefully. Note that
a. Neither the CFIA nor Health Canada provide more than the most rudimentary guidance on just what is to be measured to assess risk(5), because
b. Both assessments rest firmly on the principle of substantial equivalence as the screen to identify those GE crops in need of detailed risk assessment. Cultivars or hybrids that are found to be substantially equivalent need not undergo any specialized testing at all. Substantial equivalence is such a specious concept that, based on publicly available information, all GE crops (42 registered in Canada and 44 registered in the US) have been found to be "substantially equivalent" to conventionally bred crops - meaning none have been subjected to any more testing than conventionally bred crops..
Thus, there is no need for (a), because
of (b). In a strongly worded commentary in the most recent issue of Nature,
Millstone and colleagues at the University of Sussex, in England contended
that "substantial equivalence is a pseudo-scientific concept because it
is a commercial and political judgement masquerading as if it were a scientific
one....It is, moreover, inherently anti-scientific because it was created
primarily to provide an excuse for not requiring biochemical or toxicological
tests."
| Even Andrew Chesson, who chaired the committee issuing the supposedly "damning" audit report in the case of Arpad Pusztai, told the Royal Society of Chemistry that current tests "may be insufficient" to detect new chemicals inadvertantly produced in GE crops (Daily Express UK; 7 Sept. 99). He reportedly acknowledged the potential that inserting novel genes in a crop background can elicit unintended and unpredictable metabolic changes, leading to novel human health risks. |
The principle of substantial equivalence relieves industry of the need to look for potential risk factors, with the fortuitous and entirely predictable outcome that none are found. But while expedient, is it scientifically sound or ethically responsible - as inferred by Conway in his scathing lecture to Monsanto - for agricultural scientists to really condone the charade that GE poses no unusual risks - or liabilities?
| Table 1. Ecological risks of GE organisms, as defined by the Ecological Society of America (Tiedje et al., 1989) | |
| ESA No. | Type of Risk |
| 1 | creation of new pests |
| 2 | enhancement of existing pests, through transferral of fitness-enhancing traits |
| 3 | harm to nontarget organisms, as through broadening a host range |
| 4 | disruptive effects on biotic communities, as through competition/interference |
| 5 | disruption of ecosystem processes, as the effect of expressing microbial ligninases on decomposition and cycling |
| 6 | incomplete breakdown of hazardous chemicals (as in reclamation applications) |
| 7 | squandering of priceless biotic resources, as Bt |
Time does not permit full consideration of each of these identified risk areas, so attention will focus on Pest (Weed) Creation/Augmentation and to a lesser extent, Ecological Disruption. The central thesis is that the arguments that have been employed historically to discount environmental and food safety concerns have not been informed by contemporary understanding of crop science, whether crop ecology and evolution or pest and microbe dynamics.
Pest (Weed) Creation/Augmentation. Transfer of fitness-enhancing genes to compatible recipients, including wild/weedy relatives or neighboring crops, is of concern because of the potential:
1. Apples and Oranges. First, at a theoretical level, the potential for pest creation by GE entities cannot be gauged by the outcomes of conventional breeding specifically because GE creates entirely new constructs. A pest is any organism that is "out-of-context", whether an exotic introduction or a novel GE combination. Indeed, from an ecological perspective:
"Organisms with novel combinations of traits are more likely to play novel ecological roles, on average, than are organisms produced by recombining genetic information existing within a single evolutionary lineage" (Tiedje et al., 1989)
Thus, the long history of experience with conventional plant breeding is not a meaningful predictor of the risk - or lack thereof - of GE crops. An exception would be the general principle that protracted use of any severe screen will select for resistance in the target organism, regardless of whether the screen is a plant pesticide (Bt) or a chemical spray (Roundup)
2. Crops as Weeds/Genetic Pollution. Volunteer transgenic crop plants are themselves weeds, particularly in crops following canola or other crops which readily shatter. As in the case of any crop that volunteers, both the offending party and the "harmed" party is the same farmer who grew the GE crop.
However, for small-seeded crops, seed can also move beyond field boundaries into adjoining land - like spray drift - or via combines and haul trucks into grain bins. GE seed pollution adversely affects not just crop eligibility for GE-free premium prices but also herbicide control problems the following year. Like spray drift, the offending party should be culpable, if s/he can even be identified. However, unlike spray drift, the offending party is at least arguably not the farmer who planted the crop in good faith but the industry which sold it.
For example, Brown et al. (1996) surveyed 20 fields in Idaho and Washington, and reported finding escaped canola plants in both roadsides and ditches. They interpreted this finding as evidence that seed can move widely throughout a region. Thus, escaped crop plants - and most especially small-seeded crops like canola and alfalfa - may constitute a potential weed threat analogous to what has been claimed by Percy Schmeiser - a Saskatchewan farmer currently being sued by Monsanto for allegedly retaining GE seed.
Genetic pollution, by which pollen from GE crops inadvertantly pollinates neighboring fields of the same crop, is an additional vehicle by which crops become weeds (MacArthur, 1998a and b). As in the case of seed mobility, this "weed" is in someone else' field.
The term "genetic pollution" refers to the fact that pollen moves - sometimes great distances. Outcrossing to pollinate neighboring fields did not originate with genetic engineering, fair enough. But never before in the history of plant breeding have the outcrossing traits been potentially deleterious, and hence, actionable on the part of neighboring farmers. When transgenic pollen moves, it carries with it transgenic traits - like herbicide resistance. Pollen of canola can move 8 km, while that of both corn and potato can move about 1 km. Gary Stringam, a professor at the University of Alberta has found that canola could outcross and produce 5-6% contaminated plants up to 400 m from the original source (MacArthur, 1998b). A recent study in the UK found pollen from GE-canola contaminating bee hives up to 4.5 km from the source field. All of this makes it difficult to imagine how Monsanto and others can hold onto their precious genes - or for farmers to avoid genetic pollution by commercially costly transgenes - either moving to your fields from your neighbors, or to your neighbors fields from your land.
Consider the case of Tony Huethers, who farms near Sexsmith, Alberta. In 1997, he planted two fields, separated by 30 m, to canola. On the west side, he planted Quest, a Roundup (glyphosate)-resistant cultivar, while on the east side, he planted 20 acres of Innovator, a Liberty (glufosinate)-resistant cultivar, and the rest of his 140 ac field to 45A71, a cultivar that is resistant to Pursuit (imazethapyr, an ALS inhibitor) and Odyssey.
In spring of 1998, two applications of Roundup to the east field - the one sown in 97 to Innovator and 45A71 - killed all his weeds, except for a healthy population of blooming canola! It was apparently, and predictably, Roundup resistant canola, and was thickest near the road.
The biotech manager for Monsanto in Saskatoon
- Aaron Mitchell - said "We always expected a level of natural outcross
would occur within the species", and that the source was likely native
pollinators. He stated that the potential for cross pollination was already
well known to seed campanies and researchers, and that "farmers need to
talk to their neighbors about the canola they grow"(MacArthur, 1998a).
| What is your recourse if your non-GE crop is contaminated by GE pollen and you were aiming for a GE-free market? With GE crops selling at a discount because major clients don't want to buy them, genetic pollution poses a clear risk to every farmer, not just organic farmers. Consider a 26 August 99 letter from Consolidated Grain and Barge Company (of Indiana; 812 838-4017) to its producers: "Segregating 'non GMO' grains on farm will pay dividends this year....testing standards and tolerance levels will be very tight and any contamination, no matter how trivial it may seem, will lead to a positive test and will be rejected for 'non GMO' premiums....". And just where would you turn to recover the profit lost due to some stray Bt pollen? |
As is clear from the above example, genetic pollution is a significant problem not just for organic farmers, for whom genetic pollution can actually result in de-certification, but for every farmer.
An article in the UK Farming News (18 June 99) notes that farmers are increasingly unwilling to grow GMO trials on their farms, specifically because of fears of legal damage claims from neighbors. One underwriting manager, Sid Gibson, reportedly advised that
"The big unknown is where there is a risk of cross-contamination. Farmers considering growing GM crops should get their legal advisers to look at the contract very carefully. Responsibility should be with the biotech company or institution carrying out the trials."
Our cousins across the pond are taking a forthright look at the legal implications of potential genetic pollution from GE crops - why aren't we?
3. Superweeds? Industry proponents routinely discount concerns about the creation of "superweeds" via transfer of transgenes (or any genes) from crops to weeds. One frequently hears that because virtually all crops evolved elsewhere (e.g. not in North America), there cannot be any wild weedy ancestors for crops to cross with.
However, this is wrong. True enough that wild and weedy ancestors (of modern crops) didn't evolve here, but they are here now. Indeed, despite the fact that virtually all North American crops evolved elsewhere, wild or weedy relatives now exist in North America for many important crops (Table 2). Thus, contrary to conventional wisdom in some circles, weed generation or augmentation is a significant risk in North American agriculture. And of course, from a global perspective, which is most certainly the vision of the "let the harvest begin" proprietors of GE crops, nearly all food and fiber crops have close relatives which are considered to be weeds somewhere in the world.
| Table 2. Examples of crops cultivated in the US which have wild/weedy relatives (same species or genus) in the US (adapted from Rissler and Mellon, 1996) | |||||||
| Fiber | Fruit/Nut | Grass/
Cereal |
Legume | Oil Crop | Vegetable/Herb | Misc. | |
| Cotton | berries(6) | alternative grains(7) | alfalfa | canola | artichoke | herbs(8) | mustard |
| flax | cherry | forages(9) | peas | peanut | asparagus | lettuce | sugarbeet |
| peach | millet | sunflower | brassicas(10) | pepper | tobacco | ||
| pecan | rice | carrot | potato | ||||
| plum | small grains(11) | celery | radish | ||||
| walnut | sorghum | cucurbits(12) | spinach | ||||
| sugarcane | eggplant | tomato | |||||
Now, the presence of potentially crossable relatives does not necessarily mean that they are sexually compatible or that crossing does indeed occur, or that the trait would persist in the wild community.
Nonetheless, Ellstrand (1996) reported that of the 30 most important crops (in terms of acreage grown) in the United States, over half co-occur with at least one wild weedy relative somewhere in North America, and of these, some degree of sexual compatibility with the sown crops was common. He noted further that in some cases, as rye, sorghum, rice, and beets, hybridization with weedy relatives had already led to more aggressive weeds.
It should be further recognized that processes relating to making transgenic plants may, in fact, enhance the potential for outcrossing to wild ancestors. Bergelson et al. (1998) compared the ability of transgenic vs. mutant Arabidopsis thaliana plants to cross with wild-type plants. A. thaliana is a highly selfing species, for which risk of outcrossing is considered negligible. Both the transgenic and mutant "father" plants expressed the same mutant allele - Csr1-1 - conferring resistance to the herbicide chlorosulphuron. Per-plant outcrossing rate was 0.3% for mutant fathers compared to 6% for transgenic fathers - a roughly 20-fold enhancement. Further studies revealed that two transgenic lines differed in their ability to outcross, with rates differing from 1.2% to 10.8%. While A. thaliana is not itself a weed, this study reveals that transgenically inserting the Csr1-1 allele - which has already been introduced into dozens of crops and is intended as a selectable marker for plant transformation vectors - could enhance the potential for outcrossing even in strongly selfing plants.
In sum, risk of outcrossing to produce new or more problematic weeds is a real issue even in North America - to say nothing of the enormous risk of intentionally targeting the Third World - home of most crop plants - for GE release. Reproductively compatible close relatives exist, and often co-occur, with many important North American crops. Weeds have been created or worsened by introgression of crop genes, and the process of genetic engineering could inadvertantly exacerbate this problem, as by promoting outcrossing in the case of A. thaliana.
Traits which are most likely to be retained in crop:weed hybrids are those which confer fitness, as by altering invasiveness, conferring winterhardiness, insect, or disease tolerance, or herbicide resistance. However, as noted by Rissler and Mellon (1996 p.50), neutral transgenes may also persist due to swamping (repeated flow caused by large scale repeated plantings), or by linkage to other valued transgenes. And many current transgenes can indeed be valuable to both volunteers and crop:weed hybrids. Stewart et al. (1996), for example, documented the enhanced fitness of Bt canola vs. unmodified Bt escapes, when subjected to moderate to heavy insect attack. Snow et al. (1996) observed the unintentional movement of rust resistance from cultivated to weedy sunflower, resulting in enhanced fecundity in the crop:weed hybrid where rust was problematic.
One of the ten worst weeds in the world, johnsongrass, hybridizes freely with cultivated sorghum and is likely to retain either neutral or positive transgenes in an agricultural setting (Arriola and Ellstrand, 1997). Patterson and Chandler (1996) emphasize that johnsongrass is problematic not simply in sorghum, but also in maize, soybean, cotton, and other crops. They consider that the exposure of transgenic sorghum to johnsongrass on 8 million acres in the US "presents an enormous opportunity for gene exchange, even if such events are relatively rare."
A few of the many examples of studies into
crop:weed hybridization are presented in Table 3.
| Table 3. Examples of gene flow, hybridization, and enhanced weediness attributable to transgenic crops cultivated in the US | |||||||
| Crop | Weedy Relative or Recipient | Distance of Pollen Travel | Evidence of Crossing | Fitness/Persistence of Hybrid | Reference | ||
| canola (Brassica napus) | wild radish (Raphanus raphanistrum L.) | Male-sterile transgenic plants pollinated by weedy relative - transgenic transmission was maternal | F1 hybrids had poor fertility, but became more fertile with successive generations and resembled wild radish | Chevre et al., 1997 | |||
| birdsrape mustard (B. rapa L.)(13) | At least 26 m, but varied with weather and windspeed | a few (1:1000 seedlings tested) were herbicide-resistant hybrids | 2 F1 plants produced viable seed; weak F1 hybrids but when backcrossed to either parent, were as vigorous and high-yielding as either parent species | Brown et al., 1996 | |||
| B. rapa | hybrid superior to wild parent during establishment phase | Linder and Schmitt (1995) | |||||
| oilseed rape (B. rapa) | B. campestris | transgenes for herbicide resistance expressed in F1 and BC1 | Mikkleson et al., 1996 | ||||
| radish (Raphanus sativa) | wild radish | hybrid showed superior total seed set, compared to wild parent | fitness correlates of hybrid exceeded those of wild parent | Klinger and Ellstrand, 1994 | |||
| sorghum (Sorghum bicolor) (2n) | johnsongrass (S. halepense) (4n) | At least 100 m in both years and at two separate research stations | declined with distance, but as high as 2% at 100 m; frequency varied over test statio ns and years | hybrids showed no significant increase or decrease in time to flowering;
tiller, panicle, or seed production; pollen viability; or biomass - fitness
unchanged from johnson
grass |
Arriola and Ellstrand, 1996 and 1997 | ||
| strawberry (Fragaria x ananassa) | F. virginiana | species co-exist, are interfertile, have overlapping flowering times, and share common pollinators | Spira et al., 1996 | ||||
| alfalfa (Medica-go sativa) | alfalfa | Greater than 400 m | Skinner and Peaden, 1993 | ||||
| potato (Solanum tuberosum) | various wild relatives | cites reference for pollen movement on bumblebees up to 5 km | crossability increased from Rotata to Tuberosa (wild) and Tuberosa (cultivated) | Jackson and Hanneman, 1996 | |||
| commercial potatoes | at least 1100 m | transgenic traits transferred to nontransgenic potatoes | Skogsmyr, 1994. | ||||
| sunflower (Helian-thus annuus) | wild sunflower (Helianthus annuus) | At least 1000 m | spontaneous hybridization common (a 6.4 km isolation zone recommended for sunflower seed nurseries (Smith, 1978) | regional differences in comparing wild to crop/wild hybrid fitness; hybrids marginally less vigorous in some traits; however, hybridization inadvertantly transferred rust resistance which gave a 24% advantage in seed production to the hybrids when rust present | Arias and Rieseberg, 1994; Snow et al., 1996 | ||
| rice (Oryza sativa) | wild weed rice (same species) | readily hybridizes | progeny show marked morphological convergence to the weedy parent | Langevin et al., 1990 | |||
In sum, risk of outcrossing to produce new or more problematic weeds is a real issue even in North America - to say nothing of the enormous risk of intentionally targeting the Third World - home of most crop plants - for GE release. Reproductively compatible close relatives exist, and often co-occur, with many important North American crops. Weeds have likely been created or worsened by introgression of crop genes. Many of the genes targeted in GE crops will confer a selective advantage to weeds growing in an agricultural setting (e.g. herbicide tolerance), while others are likely to be advantageous away from sown land as well (Bt; winterhardiness; salt tolerance, etc.).
To a very large extent, agriculturalists - including agricultural scientists - are unaware of our enormous dependence upon "nature" to make things work in the world, including in agriculture. For a good general review on this, see Spedding et al. (1981). More recently, a group of 13 ecologists, economists, and geographers headed by Costanza (1997) calculated the dollar value of all the "services" supplied by the natural environment to humankind. They came up with a figure of $33 trillion, in the form of 17 distinct service areas such as N-fixation, erosion control, pollination, and biological control of pests. They argue that it is essential to give due weight to the natural "capital" that supports and sustains so much of human endeavor, to avoid making potentially disastrous policy decisions.
It has been said that GE poses a greater risk than biocides or even nuclear power. This may seem an extreme position until you consider that GE organisms are alive and are fully capable of distributing transgenes into other organisms, with unknown and unknowable consequences. In addition to effects directly attributable to the transgenic organism itself, we must acknowledge the very real likelihood of horizontal gene transfer into other, unknown genetic backgrounds (Bergmans, 1992; Kruse and Sorum, 1994). For example, Hoffmann et al. (1994) recovered transgenic DNA from a common soil fungus after transgenic crops had either grown on the land or been soil incorporated. Horizontal gene flow, which is an entirely natural and normal process, is fully capable of transferring antibiotic resistance genes, as well as genes coding for resistance to virus, bacterial, and other diseases, into unrelated organisms, potentially disrupting the structure and integrity of the soil ecosystem.
Such matters need to be front-and-center in "risk assessment" discussions, because recent research is showing the direct effect of GE interventions in disrupting ecological processes, with potentially adverse outcomes. Many papers published by GE advocates clearly do not see these risks (Feitelson et al., 1992). A few brief examples will suffice to make the point:
Soil Processes: Genetically engineered Klebsiella planticola , a common soil bacteria, was genetically modified to transform plant residues into ethanol. However, it not only competed well with parental strains, but also with beneficial soil mycorrhizae and actually killed the test wheat plants (Holmes et al., 1998). Unmodified parental strains did not have these effects..
Doyle et al. (1995) reported that Pseudomonas putida which was genetically engineered to break down 2,4-D not only broke down the herbicide but also killed soil fungi which are an essential component of both soil fertility and plant disease protection.
Tapp and Stotzky (1995) demonstrated that active BT-endotoxins (as are synthesized by Bt-plants) can persist for extended periods in the soil, bound to clay particles where they are resistant to breakdown by soil microbes. There is thus the potential for the accumulation of active BT endotoxins in the soil, with unknown long-term effects on soil processes. Because Bt-plant residues contain active toxins, rather than the inactive prototoxins which are synthesized by the original bacterium Bacillus thuringiensis itself, and which require solubilization and enzymatic cleavage to yield active toxins. As a result, Crecchio and Stotzky (1998) emphasize the risk that transgenic Bt crop residues may affect be much less selective, affecting a range of insects which would otherwise have been shielded by the very specific relationship which has evolved between bacillus and target insect hosts. Look for a related article by Stotzky and colleagues in an upcoming issue of Nature. The concern here is the ability of other organisms to take up extracellular, soil-bound DNA, including genes coding for antibiotic resistance and Bt, with unknown adverse effects on soil processes (Haack et al., 1996).
Donegan et al. (1997) studied the post-harvest effects of proteinase inhibitor I - another insecticidal protein - in buried GE tobacco residues. Compared to unmodified (parent plant) tobacco residues, transgenic residues altered the species composition of the soil biota responsible for organic matter decomposition and nutrient cycling. Species composition and balance in fungal feeding nematodes, which has been shown to influence N mineralization and plant growth, was altered by the transgenic residues.
In the aggregate, then, the potential is clear for GE entitities, both microbial and crop, to affect biological processes in ways which could compromise the ability of the soil to perform the "services" we demand of it.
Biological Control. A key concern with both GE and chemical approaches to pest control is unintentional and adverse effects on non-target organisms. Indeed, target-specificity is reportedly one of the chief advantages of the Bt-approach to pest control. But does it work?
Chapman and Hoy (1991) showed that Bt var. tenebrionis wettable powder, which is specific to Coleoptera, was shown to affect not simply two-spotted spider mite (Tetranychus urticae Koch), but also western predatory mites (Metaseiulus occidentalis (Nesbitt).
In Scotland, Birch et al. (1997) found that ladybugs (Adalia bipunctata) which fed on peach potato aphids ((Myzus persicae) which had in turn fed on GE potatoes(14) produced up to 30% fewer progeny and lived only half as long as ladybugs feeding on aphids which had fed on conventional potatoes. A similar finding was reported from Switzerland, where the BT endotoxin from transgenic corn killed most cornborers, but the green lacewings which fed on the cornborers were also killed. Green lacewings, a beneficial insect, also died when fed on African cotton worm, which had survived feeding on BT corn.
In an Internet communication, Altieri (1998) commented that the aphids in the Birch et al. (1997) study had apparently sequestered the BT endotoxin and succeeded in transferring it to predators, in this case, the ladybug. He cited further evidence that the phenomenon of toxin sequestration followed by transfer from herbivore to parasite was not uncommon in nature. Movement of the debilitating impact of BT endotoxins through soil invertebrate communities, with consequent impacts on soil organic matter and nutrient cycling, could have far reaching effects on ecosystem function.
Many other examples exist, particularly in regard to the loss of selectivity of Bt when inserted transgenically. However, as a whole, striking parallels are evident between the evolution of GE technology and that relating to biocides. It might have been hoped that contemporary GE decision-making would have benefitted from the lessons of biocide-based agriculture.
You are encouraged to take a pro-active stance on these issues. Fund the growing population of researchers who are willing and able to contribute to addressing these risks. Do this in an open and above-board fashion that unites, rather than polarizes, the scientific community and consuming public. Do this in your own best interest. It is time.
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Arriola, P.E. and N.C. Ellstrand. 1996. Crop-to-weed flow in the genus Sorghum (Poaceae): spontaneous interspecific hybridization between Johnsongrass, Sorghum halepense, and crop sorghum, S. bicolor. Amer. J. Bot. 83(9):1153-1160
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Other fundamentally insoluble problems include the impossibility of making pollen behave (e.g. genetic pollution and the plethora of consequent lawsuits), the unavoidable problems of resistance to either plant pesticides or applied herbicides (e.g. Roundup) - both of which are already occurring; the uncontrollable, ramifying effects caused by the reduced selectivity of GE-Bt and other plant pesticides, together with the compounding effects of mutation in the transgenic organism itself, or simple gene flow - via sexual and horizontal means - into wholly unpredictable genetic constructs, with unknowable ecological and health consequences
2. $400 million federal, $250 million provincial, plus $55 million for the National Biotechnology Strategy - all of which, apparently, is contingent upon private sector contributions
3. The Regulatory Directive Dir 94-08: Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits can be found at the website ( http://www.cfia-acia.agr.ca/english/food/pbo/dir9408c.html) of the Canadian Food Inspection Agency (CFIA). The CFIA is the agency responsible for ensuring environmental risk assessment of GE crops in Canada.
4. Guidelines for the Safety Assessment of Novel Foods (Vol. I and II) in Canada are found on the website of Health Canada, the agency responsible for overseeing the food safety of GE crops (http://www.hc-sc.ge.ca).
5. And they accept the most ludicrous kinds of data as evidence of non-risk. For a point by point analysis of one recent Decision Document, see Clark, 1999 (http://www.plant.uoguelph.ca/research/homepages/eclark/assumptions.htm)
6. Blackberries, blueberries, cranberries, raspberries, strawberries
9. Bluegrass, fescue, ryegrass
10. Broccoli, cabbage, cauliflower, turnip
12. Cucumber, melon, pumpkin, squash
13. Under natural field conditions, black mustard, wild mustard, and birdsrape mustard were found to hybridize and produce seed more readily than canola x weed species
14. Engineered to contain lectin from snowdrops, which is known to interfere with insect digestion