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Viewpoint: Grist for the genetic engineering mill

This article originally ran at Forbes and has been republished here with permission of the author.

A “what I’ve learned about GMOs” (“genetically modified organisms”) end-of-the-year column by Nathanael Johnson, Grist’s food writer, would ordinarily not warrant much attention (from me, at least), but this one was cited by the New York Times’ Andy Revkin as “a rich series of reports” on various aspects of the subject.  Revkin also quoted Grist’s own description of Johnson’s articles as “a level-headed assessment of the evidence in plain English [which is] in pretty short supply.”

Unlike many journalists who write about genetic engineering, Johnson makes a real effort to get it right, and in much of his piece (which contains many links to his earlier, more detailed articles), he succeeds (except for an unfortunate tendency to give a lot of ink to notorious anti-biotech liars and charlatans).  But Johnson suffers from the non-expert’s incomplete understanding of the nuances concerning the continuum of genetic engineering technologies.  Especially disappointing was his discussion of the differences between “conventional” plant breeding genetic engineering techniques and more recent molecular genetic engineering.  That point is critical because the misconceptions that molecular genetic engineering is somehow fundamentally different from its precursors, and that its products constitute a distinct “category,” underlie activists’ and regulators’ antagonism toward the newer techniques.

Johnson provides a generally accurate and clear description of radiation-induced mutagenesis – a “conventional,” or older, technique — and the newer molecular recombinant DNA techniques. Inexplicably, however, he fails to mention a critical link that lies between those two on the continuum of genetic improvement technologies – namely, “wide cross” hybridization.

As Johnson explains, genetic modification, considered broadly, has been with us for a very long time.  Farmers and plant breeders have performed selection and hybridization for millennia. Whenever plant breeders have exhausted the genetic resources (germplasm) within their crops’ species, they have used a variety of techniques to introduce new genes or alleles into their cultivars.  A genetic modification technique in use since the 1950′s, for example, is induced-mutation breeding, which involves exposing seeds or cells to ionizing radiation or toxic chemicals to induce random, desirable genetic mutations (which are inevitably accompanied by innumerable, other, uncharacterized genetic changes, some of which may be deleterious).

Thousands of such mutation-bred crop varieties have been commercialized in North America and Europe and are integral parts of our diet, and two varieties of desperately needed, rust-resistant wheat created this way were approved recently for distribution in Kenya.  But there is an important “intermediate” between mutagenesis and molecular genetic engineering that Johnson fails to mention: Since the 1930′s plant breeders have performed “wide cross” hybridizations, in which large numbers of “alien” genes are moved across what used to be thought of as “natural breeding boundaries” to create plant varieties that cannot and do not exist in nature.  In these hybridizations, which are performed between organisms of different species or genera, the parental plants may be sufficiently compatible to produce a viable zygote but not compatible enough to permit the normal embryo or endosperm development that would result in a mature plant.  Scientists devised mechanical and biochemical ways to “rescue” the embryos and make them viable, and common commercial crops derived from wide crosses include tomato, potato, sweet potato, oat, rice, wheat, corn and pumpkin, among others.

Wide-cross hybridizations and radiation-induced mutagenesis represent far more drastic “tinkering with Nature,” and create far greater attendant uncertainty about the results than the modern molecular techniques, but it is only the latter that have been subjected to onerous government regulation and the opprobrium of activists.  Johnson touches upon this paradox indirectly: “Those of us who are suspicious of genetically engineered foods need to be thoughtful… It makes no sense to protest GMOs while accepting that irradiated organic mutants should be exempt from any special regulation.  It makes no sense to try to ban all genetically engineered foods if we aren’t concerned about the rice-to-rice transfers that people like [University of California researcher Pam] Ronald are doing.”

I’d have reversed Johnson’s argument: It makes no sense to accept irradiated mutants and wide cross hybrids uncritically and uncomplainingly – even in organic farming — while railing against and resisting plants crafted with the more precise and predictable molecular genetic engineering techniques.

Wide crosses, which mix large numbers of genes chaotically, unquestionably produce more uncertainty about potential weediness, allergenicity and toxicity than either molecular genetic engineering or intra-species gene transfers.  Having said that, I should emphasize that plant breeders who use either the older or newer techniques are aware of the limitations of the technologies and perform extensive testing for agronomic and other traits.  New commercial plant varieties, however they are crafted, have proven to be extraordinarily safe.

In view of his generally accurate description of radiation-induced mutagenesis and molecular genetic engineering, Johnson’s answer to the question of whether the latter is more likely to create “unforeseen changes” than “other forms of plant breeding” is puzzling.  His conclusion is that such dangers are “slightly” more likely, but for the reasons discussed above, that is simply untrue.  The greater precision and high degree of characterization of the genetic changes that result from molecular genetic engineering make it far more predictable.

One of the questions Johnson poses is whether there are professional or reputational dangers for individuals who oppose the “accepted paradigm…that genetic engineering is basically safe,” analogous to the tribulations of Copernicus and Galileo.  Well, it turns out that most far-outside-the-box thinkers who challenge accepted paradigms – who claim, for example, to have invented herbal mixtures that cure cancer or perpetual motion machines – are not, in truth, misunderstood, persecuted visionaries, but cranks.  Likewise, the handful of rogue scientists who have reported “experiments” showing alleged hazards of molecular genetic engineering have been criticized not for challenging the “accepted paradigm,” but for being incompetent, negligent or fraudulent.  (See examples here and here.)  Johnson appears to soft-pedal such misbehavior.

On balance, Johnson’s articles do much to debunk some of the mythology and propaganda of the anti-biotechnology lobby.  I just wish he had dug a little deeper on some of these issues.

Finally, the New York Times’ Revkin, who himself is a straight shooter and strives to get the facts right, is correct that “there’s a broader point to ponder here.  The interplay of Johnson’s reporting and that of other writers…is more illuminating than any single voice.”  He’s only partially correct.  Some high-profile reporting and writing about genetic engineering – notably, that of his Times’ colleagues Keith Schneider, Andrew Pollack, Michael Pollan and Mark Bittman – have provided not illumination, but only obfuscation, bias and propaganda.

Although it is true that we benefit from shopping in the marketplace of ideas, we should also recall the admonition of Daniel Patrick Moynihan: “Everyone is entitled to his own opinion, but not to his own facts.”

Henry I. Miller, a physician, is the Robert Wesson Fellow in Scientific Philosophy & Public Policy at Stanford University’s Hoover Institution.  He was the founding director of the FDA’s Office of Biotechnology. Follow him on Twitter @henryimiller

Related article:  Wine Spectator article outlines how GMOs might help wine industry
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