St. Louis Post-Dispatch / March 17, 1999
As we prepare for the next millennium, perhaps the most significant issue to be resolved is how genetic engineering will be used to affect our food supply and human health, as well as all plant and animal life.
Continuing riots in underdeveloped countries, and opposition by many other nations, against engineered foods, underscore the importance of genetic engineering. Why the opposition?
The greatest long-term threat of engineered food is the loss of genetic diversity in agriculture. Until about four decades ago, most farmers practiced plant rotations, planted a diverse mix of crops and collected the seeds from the best plants for sowing next year's crops. Thousands of independent farms had a patchwork of species each with the unique variety selected by the farmer. These practices maintained not only the natural diversity of the country's
agricultural plants but also of the nutrients and microorganisms in the soils.
The introduction of high-yielding hybrid corn in the 1950s revolutionized agriculture. The seeds from the hybrid corn did not reproduce the hybrids, and farmers became dependent on the large seed companies to buy new corn seeds every year. The hundreds of different varieties in the nation's plantings were replaced by a very few chosen by the seed companies for distribution to all farmers.
The result was a loss of genetic diversity and with it the potential for catastrophic consequences to our largest and most important crop.
The problem is that some varieties of any plant are resistant to a lethal pest while others are not. Restricting a crop to only a few varieties increases the risk of a given parasite wiping out most, or all, of that crop.
For example, in 1970 a Bipolaris fungus spread wildly through America's corn crop. Fortunately, dry weather in September arrested the epidemic, and losses were limited to only 1 billion bushels or 15 percent of the harvest. The
National Academy of Science concluded: "The key lesson of 1970 is that genetic uniformity is the basis of vulnerability to epidemics."
Nonetheless, pressure for uniformity and yield have led to monoculture farming, with fewer varieties of potatoes, beans, rice and other major crops. As a result, agriculture has become more dependent on pesticides and fertilizers to combat pests and increase yields.
This type of farming has led to a cost of $40 billion a year in the United States for 1.2 billion pounds of pesticides, which have caused enormous ecological damage and contributed to illness and premature death of many people.
It has contributed to dependence on chemical fertilizers with averages of 110 to 490 pounds of nitrogen per acre, much of which ends in our aquifers causing more than 25 percent of our drinking water wells to contain nitrate (deadly for infants and some animals) above the safety limit of 10 parts per million.
Since resistance develops, there is a continuing need for newer and stronger poisons. More insecticides are used on corn than any other plant. In 1945, about 3.5 percent of the corn crop was lost to insects; it is now 12 percent,
even while insecticide use has increased at least 1,000-fold.
In 1996, 270 weed species were known to be resistant to herbicides (often to a spectrum of agents). Ryegrass in Australia was shown recently to have developed resistance to Monsanto's Roundup, the world's best-selling
herbicide.
However, hybrid technology could not be applied to many commercial crops, such as soybeans, wheat or to large farm animals. Enter genetic engineering.
It took decades to develop hybrid corn, but introducing genes from another species into the genome of a plant, or even animal, can now be accomplished in a few years with the major crops. With prospects for a more successful yield in a given year, subsistence farmers around the world become dependent on the giant agri-chemical companies for genetically engineered seeds that are resistant to the herbicides or pesticides often sold by the same company.
The new life forms are patented. Like hybrid corn seeds, they have to be re-purchased every year to avoid severe penalties. A more surefire means to ensure farmers' dependence on the agri-companies is to incorporate foreign genes that render the plant seeds infertile. The first of these was the "terminator" gene, and many patents are pending on variations of this technology.
One of the most ominous long-term concerns is the increasing recognition that introduced genes, such as terminators, can travel to nearby related weed plants, which could lead to widespread and unknown ecological consequences. To meet this challenge, companies have patents pending on "suicide" genes, which can be turned on or off only by exposure to an externally applied patented
chemical.
As with corn, the hundreds of varieties of a crop generated each year could be replaced worldwide by a small number of genetically engineered varieties that can be grown only after applications of specific chemicals marketed by the
same agri-chemical corporations.
The ecological risks are not limited to the plant world. For example, a Bacillus soil bacterium produces the Bt insect toxin, which is a natural biological pesticide used by organic farmers only when needed. Introduction of the Bt gene into every cell of crop plants (corn, cotton and potatoes) amplifies its presence enormously to upset the natural equilibrium. At least eight species of insects have already developed Bt resistance. Dow Chemical scientists estimate that within 10 years Bt will have lost its effectiveness by selection of so many resistant insect, and a natural defense mechanism will have been lost.
Besides accelerating the loss of genetic diversity in our food supply, this use of genetic engineering poses other extremely dangerous risks. The complexity of an organism is not any obvious function of the amount of DNA per genome, e.g., some amphibians have 25 times more DNA than do humans (unless you think frogs are more complex).
Overall function is defined more by the complex interactions of many gene products and targets, and any single gene may be involved in more than one function. Foreign genes are introduced into a genome at a random site, which can interfere with, or enhance, the function of host genes. Unknown side effects could occur when a foreign insect gene is introduced at a random site into the genome of a tomato, cow or human. Known or unknown allergic reactions can occur from introduced protein products such as occurred in 1996 with the introduction of a specific Brazil nut gene into soybeans.
The breakdown products of herbicides or pesticides, generated by products of introduced genes, can themselves be toxic. For example, cotton has been genetically engineered to withstand spraying with the pesticide, bromoxynil, by introduction of a gene that causes bromoxynil to be degraded to a product called DBHA. However, the DBHA is itself toxic and may find its way into the human food chain from cattle whose traditional silage contains up to 50 percent cotton slash, as well as from use of cottonseed oil as a cooking additive.
As is true for most new technologies, genetic engineering can be used to the great benefit of mankind. It has led to important advances in basic research and has the potential for overproduction of valuable molecules such as human hormones from genes introduced into micro-organisms that are then grown in controlled laboratory facilities.
However, its widespread application in the uncontrolled theater of nature raises many more concerns than the few cited examples. We are performing an experiment on a world scale whose consequences are unknown and can only be imagined. It took millions of years for evolution to produce the life forms of today. In less than our lifetime we may upset the delicate balances that took those millions of years to achieve. We are playing God, but can we claim his wisdom?
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Sources
Some information for this article is from the books: "The Last Harvest, The Genetic Gamble That Threatens To Destroy American Agriculture" by Paul Raeburn, science editor of The Associated Press; "The Ecological Risks of Engineered Crops" by Jane Rissler and Margaret Mellon of the Union of Concerned Scientists; "Pest Management at the Crossroads" by Charles M. Benbrook, Consumers Union; and "Against the Grain; Biotechnology and the Corporate Takeover of Your Food" by Marc Lappe and Britt Bailey.
