Bacterial domestication: underlying assumptions.
On the basis of well-established principles of evolutionary biology and microbiology, I conclude that (i) the deliberate introduction of a novel bacterial strain to the environment is not substantially more dangerous than the accidental release of a smaller number of cells; (ii) distant organisms are less (rather than more) likely to yield dangerous hybrids than more closely related ones; and (iii) the complex attribute of pathogenicity is not likely to emerge from genetic alterations in nonpathogens. If these conclusions are correct, most engineered bacteria need not be regulated more strictly than the bacterial strains that have been tested in the field in the past. The only exceptions would be strains derived from cells, or appropriate genes, of microbes pathogenic for plants or animals. Microbiologists not only recognize the need to handle pathogens with caution: they have long accepted regulations, such as those governing transportation, that reinforce that recognition. It is remarkable that we can still be arguing, on the basis of analogies rather than firm scientific principles or evidence, about hypothetical disasters from kinds of organisms that are being produced in hundreds or thousands of laboratories without a trace of demonstrable harm. RAC required 6 years to adjust its initially conservative guidelines to the emerging understanding of the scientific realities, while maintaining public confidence. Since the level of public concern is not nearly as great today, EPA should be able to relax its excessive restrictions much more quickly. Even better would be a return to having RAC, or a single successor group, evaluate the problems of danger for all classes of engineered bacteria, since the applicable shared principles outweigh any specialized differences in the nature or use of the specific strains. But the regulations are unlikely to be unified in this way, or to be divested of unproductive restrictions, without broad encouragement from the scientific community-including, hopefully, many ecologists. The agenda has been set for too long by apocalyptic activists. To protect this promising field of research and technological application the scientific community must take initiative in helping the public and decision-makers to distinguish reasonable probabilities from remote fantasies.
Davis
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BD