Sowing those seeds of doubt

June 16, 2000

Those trying to regulate genetically modified crop trials are wasting their time and public money, says Alan McHughen

Trying to conduct a risk assessment based on gene escape via pollen is a waste of time and resources. In my petitions to place my GM plant Triffid on the market, I needed to provide a complete data set, which needed substantial expenditure of public funds to acquire. The data set addressed concerns about gene escape, the interpretation of which required further expenditure of public funds upon submission to the regulatory authorities. It was all wasted.

The UK government spends a considerable amount of money conducting research into the likelihood of a GM plant pollinating nearby plants to measure the risk of genetic escape. The hazard is the gene escape under a certain set of parameters. The exact species of GM plant is critical to the research. Rapeseed, especially Brassica rapa, is by nature promiscuous and will, left to its own devices, spread pollen all over the countryside. By contrast, wheat is almost completely self-pollinating. The risk of escape of a gene from a GM wheat is lower than the risk of escape of a GM rapeseed.

One component of these studies is the calculation of possible pollen recipients. This involves finding populations of the same species growing nearby that might be recipients. This calculation has to account for managed, as well as unmanaged, plants of that species and related ones. Are any potential recipients weeds that might become more "weedy"? Are there any rare or endangered species that might become even more endangered? The scientists must also consider pollen vectors. Is this pollen spread by wind? If so, what are the weather patterns in that geographical area at the time of pollen shed? Perhaps insects transfer pollen from this species. We need to know what insects serve as pollen vectors, what their populations are in the area at pollen shed time, and where the insects are likely to go - including distance, location and so on.

Differences in pollen biology between species account for the differences in risk of gene escape. While the pollen grains within each plant species look the same, pollen from different species displays remarkable variation. Pollen grains identify plant species as accurately as fingerprints do us; they are reliable enough to be used extensively in forensic research. There can be substantial differences in shape and size, influencing wind and other vector dispersal type and range. Pollen grains can be heavy or light, also influencing dispersal mechanisms. Some species have long-living pollen, others have a very short period of viability, even a matter of minutes. Some complete pollination even before the flower opens, ensuring self-pollination. Other species have self-incompatibility mechanisms to preclude self-pollination, ensuring cross-pollination. If we are going to measure risk of gene escape through pollen at all, these differences in pollen biology account for the need to analyse each species separately.

When these questions are all answered for each genetically modified organism in each intended geographical area, we have piles of scientific data collected by some of the best scientific minds at the best universities and institutes in the country, for which taxpayers have contributed equally huge piles of money. But at least the public can rest assured that scientifically valid risk assessments can now be determined for the risk of escape, via pollen, of genes from these GMOs.

But that is only part of the equation. Do we not have to know what will happen in the event of pollen escape? Will it result in an environmental disaster of biblical proportions? Or will it be a benign, mundane event? Surely the magnitude of the consequences influences the assessment. Back to the scientists, back to the public trough. Big science will calculate what will happen to the environment in the event pollen does escape and fertilise some unsuspecting plant across the road. Again, we have to consider the parameters. If the trait is pesticide resistance, we have to determine how each potential mate might act having acquired the pesticide resistance.

All these questions are complicated by the fact that, in many cases, we have to make guesses - educated, mind you, but guesses nevertheless - about how the gene might affect fecundity in the new recipient plant. Maybe the population of the weedy relative will explode and we will be overrun with them. On the other, equally disastrous, hand, perhaps the presence of the novel gene in the plant will cause the population to diminish to extinction. More money. More time. More public scientists employed.

In most jurisdictions, including the EU/UK, risk assessments of GM plants place immense and (in my view) superfluous emphasis on questions of gene escape. Pollen flow, the type described above, is only one mechanism of genetic escape. Some plants exercise gene escape by vegetative means. That is, a piece of the plant might snap off, blow away, or be dragged by a passing animal, and take root in a new location, starting a new population. The preponderance of such vegetative mechanisms of genetic escape needs to be determined for each species. Potatoes are a common and well-known example of a plant with a predilection for vegetative reproduction. Strawberries can reproduce by runners. Leaf pieces from begonias can easily be propagated on soil. Other means of gene flow are known in the plant world, and each needs to be considered for each GM plant being reviewed.

What about birds and animals munching on the GM plants? They don't always fully digest the seeds before dropping them, complete with a dose of natural fertiliser to give the germinating seed a competitive headstart, some considerable distance from where the "confined" crop was growing. As you can imagine, calculating the incidence of all of these potential escape routes involves a huge amount of money to provide the background information on these issues.

None of it is money well spent. Regardless of how much genetic escape will occur from pollen flow or other mechanisms, it is still immaterial and a waste of everyone's time and effort, not to mention public money.

Why is it a waste? Do we not need to know about the likelihood of gene escape? No, we do not. Gene escape is a fact of nature. Period. Save the money. Cancel the projects. Let those top brains do something useful instead of trying to find hypothetical phantoms. The genes have already escaped.

Alan McHughen is a senior research scientist at the University of Saskatchewan, Canada. His book A Consumer's Guide to GM Food (US title Pandora's Picnic Basket), is published this month by Oxford University Press.

You've reached your article limit.

Register to continue

Registration is free and only takes a moment. Once registered you can read a total of 3 articles each month, plus:

  • Sign up for the editor's highlights
  • Receive World University Rankings news first
  • Get job alerts, shortlist jobs and save job searches
  • Participate in reader discussions and post comments

Have your say

Log in or register to post comments