Ecology & Genetics:

Table of Contents

Preface

Acknowledgments

Chapter 1: The Ecosystem in Us

Chapter 2: Incorporation and Excorporation

Chapter 3: Modes of Expression

Chapter 4: Reproduction of the Ecosystem

Chapter 5: Genetic Engineering and the Environment >

References

Ordering information

Human beings are now busy producing some of the most rapid changes ever known in the global ecosystem. The widespread use and misuse of antibiotics has already caused the emergence of resistant bacterial strains. Emissions of large amounts of greenhouse gases are causing as yet ill-understood changes in the in the patterns of circulation of energy and materials through various ecological cycles. Research on hormonally active pollutants (such as dioxin) suggests that they can change the expression of genes during fetal development and afterwards as well.¹ The questions of what overall genetic and ecosystem changes these types of human activities may induce and at what speed those changes might occur have hardly begun to be systematically posed.

Still, the widespread misuse of antibiotics and the introduction of many mutagenic and carcinogenic chemicals have provided ample proof that human activities can produce unintended, rapid, and possibly disastrous genetic change. In other words, severe genetic and environmental changes have already occurred due to the introduction into the environment of molecules that are far simpler than genetically engineered plants.

If the hypotheses discussed in this essay are even plausible, then we must conclude that the introduction of new forms of life into nature by inter-species genetic engineering may, at least in some cases, induce changes in ecosystems that may be substantial, unpredictable, and possibly even drastic. Inter-species genetic engineering, which uses genetic materials from widely different species, suddenly creates new genomic structures, each of which will try to create an external ecosystem structure that corresponds to an internal need-structure that is to some extent unknown. Radically new forms of life that mix genes from widely differently groups of living beings (fish genes in plants for example) could create new pressures on ecosystems.²

A hint comes from research on Bt corn and monarch butterflies. (Bt stands for bacillus thuringiensis, the bacterium that carries the gene that is engineered into the corn.) Bt corn contains a gene from bacillus thuringiensis so as to enable it to internally produce a pesticide, thus obviating the need for external pesticide application. In an experiment, Cornell University scientists applied pollen from Bt corn to milkweed, some of which grows near cornfields and placed monarch butterfly caterpillars on them, since they feed on milkweed leaves. After four days, 44 percent of the monarch larvae that fed on Bt corn leaves died, while none of the caterpillars on the control leaves that had no pollen or that had corn pollen from non-engineered plants died.³ While the ecological significance of this experiment is not yet clear, it is evident that genetically engineered corn has been introduced on a vast scale without sufficient consideration of its effects on ecosystems. If it can adversely affect monarch butterfly caterpillars so severely, how many other types of flora and fauna might it also affect? We scarcely know.

If history is any guide, some of the nastiest changes will come as surprises-as, for instance, that some artificial chlorinated chemicals behave like estrogens-because we do not adequately understand the complex correspondence of ecological, chemical, and genetic structures. As a result, we cannot realistically assess all essential aspects of the safety of genetically engineered foods for human beings, or even decide which aspects are essential for the long-term.⁵

There is even less understanding about what genetically engineered plants and animals may do to the environment. Furthermore, many changes may be undiscoverable by practical means until it is much too late to stop the damage. Diethard Tautz has suggested an "uncertainty principle" in genetics: for "genes or genetic functions that have only a very small effect on the fitness of an individual, but are nonetheless important for long-term fitness within a population," an adequate understanding may require "experiments that involve the whole population of the respective species."⁶ Of course, this means that nearly the entire population would have to be changed to discover whether deleterious changes have occurred-a genetically self-defeating proposition.

The terrible surprises that genetic engineering may hold in store were dramatically demonstrated by an Australian effort to genetically engineer the mousepox virus (which is related to the virus that causes smallpox in human beings but does not attack humans) in order to control rodent population and reduce crop damage. The mousepox virus was modified by the insertion of a gene associated with the control of the production of interleukin-4, an immune-system-related molecule. The goal of the genetic engineering was to increase the immune response of the rodents so greatly that the eggs of the mice would be rejected as foreign objects, in the way that external disease causing agents are attacked by the immune system.

The outcome was, in more than one way, the opposite of what was expected. Instead of strengthening the immune system, the genetically engineered virus suppressed it. Instead of being less lethal, the new virus was more lethal. Mortality was high even among vaccinated mice and mice bred for resistance to mousepox. In other words, the engineered virus not only defeated primary immune response, it also inhibited "the expression of immune memory responses."⁷ Surviving mice were permanently disabled.

These effects were observed during 1998 and 1999. But public discussion of them was suppressed for some time, for fear of spreading the information that it is relatively easy to create a new lethal virus-one that can even defeat vaccinations. Debate has so far centered on the potential of the technique for the deliberate creation of deadly new biological warfare agents for which no timely responses may be possible. How does one balance such possible risks of genetic engineering experiments, which unintentionally illuminate a path to deadly diseases and biological warfare, with any supposed benefits? And what about accidents arising from research, to say nothing of genetically engineered organisms now being introduced into the environment far beyond the laboratory?

The questions arising from the mousepox research are made more troubling by the fact that little independent research has been carried out on crucial ecological aspects of genetic engineering. In a review of the existing literature on the ecological effects of genetically engineered organisms published in Science, L.L. Wolfenbarger and P.R. Phifer concluded that "key experiments on both environmental risks and benefits are lacking."⁸ Specifically, the "ecological consequences in nonagricultural habitats and ecosystems" of genetically engineered organisms "remain largely unstudied" despite indications of risk from past experience with crops that are crucial to the world's food supply:

Like Tautz, Wolfenbarger and Phifer note that some effects cannot be determined from small-scale experiments:

The rub is that if it is necessary to resort to widespread planting to discover adverse effects, then it will probably be too late to do anything about the harmful effects that are discovered. As long ago as 1976, when biotechnology as a large economic prize was only a gleam in the eyes of researchers, biologist Erwin Chargaff, in a letter to the journal Science, pointed out that "you cannot recall a new form of life."¹¹

The example of the StarLink variety of corn should be taken as an early warning of this problem. StarLink is the trade name for a type of Bt corn containing the Cry9C protein. This corn variety had been approved for animal feed, but not for human consumption due to data indicating a potential for producing allergic reactions. Testing initiated by Friends of the Earth in the year 2000 showed that it was present in tortillas purchased in a supermarket.¹² As testing became more widespread, the estimates of the amounts of contaminated corn increased from 70 million bushels to 430 million bushels.¹³ The latter figure represents enough food calories to supply many millions of people with grain for an entire year.

Even though StarLink was planted on less than 1 in 5,000 acres of land planted to corn, it is now difficult to be confident that corn is completely uncontaminated. A special definition of uncontaminated corn has had to be created: it is corn containing less than 1 kernel in 2,400 of StarLink.¹⁴

In early 2001, a portion of the U.S. seed supply of corn meant for human consumption was found to be contaminated. The U.S. government is buying back several hundred thousand bags of seeds.¹⁵ In a practical recognition of the reality that StarLink corn cannot be recalled, the company that made it, Aventis, asked the Environmental Protection Agency to retroactively rule it safe for human consumption. It had not been certified fit for humans due to an unknown risk of allergic reactions.

Chargaff also noted that "[b]acteria and viruses have always formed a most effective biological underground. The guerilla warfare through which they act on higher forms of life is only imperfectly understood. By adding to this arsenal freakish forms of life-prokaryotes propagating eukaryotic genes-we shall be throwing a veil of uncertainties over the life of coming generations. Have we the right to counteract, irreversibly, the evolutionary wisdom of millions of years, in order to satisfy the ambition and the curiosity of a few scientists?"¹⁶ Profits, of course, have since come to play a larger role.¹⁷

Chargaff alludes to the very slow rate of change of natural genetic-ecosystem interactions compared to the DNA shot-gun and other engineering methods that can suddenly create new genomic structures impossible in nature. This rapid change may present challenges and uncertainties as big as those from the fact of creating new structures. While species that evolved in one local ecosystem can often adapt to new places, the ecosystems into which new species are introduced do not necessarily have a reciprocal adaptability.

The introduction of European rabbits into Australia in 1859 by a wealthy homesick landowner is a notorious example, estimated to be the "most destructive and most expensive transfer ever of an animal from one country to another." They have wreaked havoc on all forms of vegetation and overcome efforts to eradicate them whether by shotguns or imported viruses, growing in numbers from two dozen in 1859 to 300 million in 1997.¹⁸

Finally, when ill-effects are recognized, effective remedial action, if it is available at all, will, most likely, be resisted for a considerable time. For instance, it took decades before the potential of chemicals like PCBs for disrupting endocrine systems was officially recognized and a ban incorporated into an international treaty.¹⁹ Much damage has already been done and much more is inevitable since endocrine disrupters are still widespread in the environment and a large portion cannot be recovered. Industry pressure on the U.S. Environmental Protection Agency to retroactively approve StarLink corn for human consumption is an early example of resistance to even acknowledging problems in the arena of genetic engineering.

In view of the magnitude and unpredictability of the risks, biologist Richard Strohman has suggested that "biogenetic engineering of humans and of plants where unanticipated results could cause damage to individuals or to millions of acres of cropland will have to cease except under tightly controlled laboratory conditions and until the time when the complexities are understood and the dangers eliminated. Controls here would include concerns of ethical, legal, and social dimensions. These concerns must reflect the 'ethics of the unknown' of the incompleteness of the science being applied, and not just the ethical concerns growing out of a 'successful' technology."²⁰ The limitations on inter-species genetic engineering recommended by Strohman are fully warranted and urgently needed. When the effects of creating modified genomes on the environment and on evolution (including our own evolution as human beings) are well understood, we can at least have a well informed debate about genetic engineering. Today, we cannot. We are broadcasting the seeds of possible severe genetic and ecosystem damage without even making a good-faith attempt to know what we do.

Next: References