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Genetic Engineering

Why Is Release Of Transgenic Crops Into The Environment a Risk?

Conventional breeding allows mixing and recombination of genetic material between species that share a recent evolutionary history. On the other hand, genetic engineering is an imprecise, haphazard technology and is completely different from traditional plant breeding. With alarming regularity, biotechnology companies have demonstrated that scientists cannot control where genes are inserted and cannot guarantee the resulting outcomes. Unexpected field results highlight the unpredictability of the science, yet combinations previously unimaginable are being field tested and used commercially.

The nature of the process of genetic engineering produces unpredictable effects at the genetic and cellular level, which will inevitably have impacts at the ecological level. This paper highlights some major ecological concerns.

SUPERWEEDS: Genetically engineered crops were first planted in the mid 1990s. Already, research has documented that genes producing desired characteristics in crops can confer adaptive advantages to weedy species, causing problems in valuable wild plant habitats.

Research suggests that bees may be important pollen vectors over a range of distances and farm-to-farm spread of oilseed rape transgenes will be widespread. Pollen can also travel for miles in the wind and integrate its DNA into the genome of conventional plants. Genes from GEOs (genetically engineered organisms) can spread to wild plants and native species, resulting in herbicide resistant superweeds.

For example, the pollen from transgenic rapeseed (canola) can blow into neighboring farms and wild areas and can easily outcross to any nearby canola plant. The herbicide resistant traits become promiscuous and transfer to weedy relatives. The traditional weed then becomes a stronger "superweed." This outcrossing has started to produce superweeds that are resistant to a wide range of herbicides.

The 4/26/00 edition of New Scientist magazine reported the first officially confirmed case of its kind: weeds in Canada which became resistant to three kinds of herbicides: Roundup, Liberty and Pursuit. It only took three years for a transgenic spread of super-herbicide-resistance. This was the first documented case of gene stacking in canola occurring without deliberate human intervention.

The rapid outcrossing of GEO herbicide resistant plants raises serious questions for those concerned about the emergence of weeds that do not die no matter what herbicide is applied. These superweeds may very well have a bioengineered advantage in taking over farm fields and in moving through wild areas, where they are likely to have a range of impacts on populations of wild plants and wild plant habitats.

BIODIVERSITY: In the 9/18/99 Worldwatch Institute report "Farmers Losing Seed Varieties Worldwide," John Tuxill wrote that in the United States more than 80% of seed varieties sold a century ago no longer are available and that the world is rapidly losing genetic diversity in crops. With development of transgenic crops, traditional varieties may dwindle even further as farmers grow a less diverse pool of crops to obtain the highest yields for commercial production.

Bt (Bacillus thuringiensis) toxins are becoming ubiquitous, highly bioactive substances in agroecosystems. Bt crops are pumping out huge amounts of toxin from all tissues throughout the growing season, from germination to senescence. Most non-target herbivore insects, although not lethally affected, ingest plant tissue containing Bt protein which they can pass on to their natural enemies. There are also unanticipated effects on non-target insects through deposition of transgenic pollen on foliage of surrounding wild vegetation. These effects herald problems for small farmers in developing countries and for organic farmers since they rely on insect pest control. For instance, loss of lady bugs and lacewings will likely result in increased crop losses.

The Soil Association report (UK) on 6/22/99 warned, "GM code could wipe out wildlife." Birds, for instance, might lose habitat and major food sources (both plants and insects).

The spread of transgenes into the wild and the effect this will have on biodiversity may be especially severe in less developed countries and wherever native archetypal varieties of agricultural crops exist.

SOIL FERTILITY: The soil food web is crucial for plants to obtain the nutrients necessary for growth. Many crops are engineered with the Bt toxin in order to resist infestation from insects. Yet root exudates from these plants release the toxin into the soil, where it retains its activity for at least 234 days, long after its release. This stimulates major changes in soil biota that could affect nutrient cycling processes and reduce soil fertility.

Monsanto's advertising campaigns try to convince people that Roundup is safe, but the facts do not support that conclusion. Independent scientific studies have shown that Roundup is toxic to earthworms, beneficial insects, birds and mammals (in addition to destroying the vegetation on which they depend for food and shelter).

The Progressive Farmer on 1/3/01 reported a University of Missouri study which revealed that Roundup Ready soybeans receiving glyphosate at recommended rates had significantly higher incidence of Fusarium on roots compared with soybeans that did not receive glyphosate. Fusarium is one of the most economically important groups of fungi causing diseases on a wide variety of plants. Pat Donald, professor and director of the UM nematology lab was quoted as saying "We're concerned because SDS (sudden death syndrome) is showing up everywhere and can be devastating."

EFFECTS ON NON-TARGET INSECTS: Insects have their place in the ecosystem. Some play a major role in maintaining the equilibrium of insect populations and are important for pest control strategies. The Bt toxin has been shown to be lethal to non-target organisms such as Monarch butterflies, lacewings and ladybird beetles.

The issue is broader than whether Bt toxin produced by genetically modified crops imperils beneficial insects. The real issue is that a strategy to establish expression of an insecticidal compound in large-scale crop monocultures and thus expose a homogeneous sub-ecosystem continuously to the toxin can cause irreparable damage to natural habitats forever

SUSTAINABLE AGRICULTURE AND ORGANIC FARMING THREATENED: There are many alternative approaches that farmers can use to effectively regulate insect and weed populations, i.e. rotations, strip-cropping, biological control, cover crops, and green manure. To the extent that transgenic crops further entrench the current monoculture system, they impede farmers from using a plethora of alternative methods.

The entire future of organic farming is being threatened because pollen transfers by insects and the wind from GE crops to organic farms. Cross pollination can move transgenes into the crops so that, against their intentions, farmers are growing GE crops. GE seeds can also fall off trucks and farm machinery during transport or be left in the ground, leading to the growth of stray plants.

It isn't debatable if Bt resistance will develop among insects populations, the question is how fast this will occur now that the toxins are being used in huge amounts throughout the entire growing season. Bt microbes are applied by organic farmers as a surface agent (when one is absolutely necessary) and will become ineffective as an important biological insect control tool.

The problem of crop contamination not only has direct consequences for organic farmers; it also may damage our heritage of agricultural varieties, which has huge implications for populations around the world. For thousands of years, humans have selected and bred varieties adapted to unique climatic zones and regional properties. Transgenes may cause significant damage to that genetic diversity, and commercialization of a few varieties of patented seeds will also erode this vital heritage.

"Terminator" systems designed to protect seed companies' profits by ensuring that farmers can't save seed (the succeeding crop will be sterile) are a further step away from sustainable agricultural practices and respect for the diversity of our agricultural heritage.

GENE TRANSFER INTO GUTS OF BEES: A three year study by Professor Hans-Hinrich Kaatz at the Institute for Bee Research, University of Jena found a gene transfer from genetically engineered rapeseed to bacteria and fungi in the gut of honey bees. Beatrix Tappesser from the Ecology Institute in Freiburg was quoted as saying "This is very alarming because it shows that the crossover of genes takes place on a greater scale than we had previously assumed. The results indicate that we must assume that changes take place in the intestinal tubes of people and animals. The crossover of microorganisms takes place and people's make up in terms of microorganisms in their intestinal tract is changed. This can therefore have health consequences."


References:

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