“Two public relations myths about genetically modified crops”

Genetically modified (GM) crops are claimed to be the pinnacle of genetic science and they are promoted by scientists in academe, government and corporations. Two pronouncements frequently encountered during the promotion of GM crops include first, “GM crops are a simple extensive of traditional plant breeding and selection that has gone on for over ten thousand years” and second “the protein products of the transgenes in GM crops are rigorously tested to insure safety to mammals and to the environment”. Even though the statements are made by accomplished scientists those comments are not science based but are, in fact, public relations exaggeration of the scientific facts. The rapid expansion of the spread of GM crops has been promoted using the methods of public relations rather than the prime scientific dictum , full and truthful reporting. Indeed, it appears as if the promoters of GM crops have put public relations ahead of science, in a sense superstition ahead of empirical science.

The first statement “GM crops are a simple extension of traditional breeding” ignores the fact that all of the commercial GM crops were created using , as a genetic process , illegitimate recombination (inserting transgenes into a break in a chromosomal DNA strand), while all of the crops created by selection , since the beginning of agriculture over ten thousand years ago, were based on legitimate recombination (meiosis during creation of sperm and egg). Recombination and meiosis (1), along with the process of chromosome strand breakage and gene insertion (2) are reviewed in the indicated publications. When the GM crop plant is , at first, constructed the diploid plant is , at first hemizygous (bearing the insert on a chromosome but without no allele on the homologous chromosome), by selfing the plant one in four of the progeny will be homozygous , half will be hemizygous and one quarter will not have the transgene. The homozygous plants (with transgenes at the same locus on homologous chromosomes) may undergo homologous recombination at or near the transgene but homologous recombination will not have contributed to the transgenic trait nor to its selection. In contrast normal agricultural traits are selected exclusively using homologous recombination. The desirability of creating adequate systems using homologous recombination is well know in plant genetic engineering and efforts are being made to create systems that offer the stability and reliability of homologous recombination (3). Nevertheless, it is abundantly clear that no commercial GM crops have been produced using homologous recombination and claims that GM crops are genetically similar to conventional crops is a public relations promotion rather than a scientific statement. A truthful statement would be “GM crops are unique products of illegitimate recombination”, however, it is unlikely that truthful statements will aid in marketing GM foods.

Turning to the second public relations myth “protein products of the transgenes in GM crops are rigorously tested to insure their safety to mammals and to the environment” the myth is based on the direct testing of protein products. However , to save money in producing pure protein, the gene products produced in bacteria are tested in spite of the gene sequence changes and numerous protein amino acid changes made when the proteins are produced in crop plants. The numerous alterations of the transgenes and the protein sequences of Bacilus thuringiensis (Bt) crops along with the references to patents and United States and Canadian regulatory decision documents is provided in the review “Regulatory sham on GM crops” (4). The Bt toxin protein produced in crop plants differed in both gene code words that did not effect amino acid placement and gene code word changes that deleted or changed amino acids to make the protein more active in the plant cell environment, but the unaltered proteins produced in bacteria were tested not the proteins produced in crop plants. Changes are also made in the trans genes and amino acid sequences of the enzymes introduced into herbicide tolerant crop plants. For example the glyphosate oxidoreductase (GOX) gene and enzyme are altered “The GOX protein retains the same amino acid sequence as the native protein and has additional four amino acid sequence N-terminus (reminanats of an added signal sequence). In GOXv247, the gene sequence of the native protein was altered resulting in changes to three amino acids in the sequence of the resulting protein along with the remains of the added signal sequence mentioned previously. These changes did not negatively affect the enzymatic activity of either protein.” (5) The altered protein produced in the GM crop was not tested for safety to environment and mammals but the unaltered bacterial protein was. The bacterial Phosphinothricin Acetyltransferase (PAT) gene was introduced into crop plants to produce resistance to the herbicide glufosinate and as in the previous discussion the bacterial enzyme was tested for safety while altered genes and enzymes were produced in the GM crops (6). In most instances the regulatory evaluators accepted the presumption that so long as the insect toxic properties or the enzyme activities of the proteins were not lost that the altered proteins produced in GM crops could be assumed to safe as the unaltered proteins produced in bacteria. Such assumptions are , though friendly to corporations, not scientifically sound and the tests should have been done on the proteins produced in crop plants. Nevertheless, since the GM food produced from GM crops is not labeled in the market the injury and side effects from the untested gene products will go undetected. Regulation has grown slovenly because the regulators are aware that the unlabeled GM foods cannot readily be traced back to them , in the event they permit toxic products to be marketed.

In conclusion, public relations assurances dominate the promotion of GM crops. Science’s prime mandate, full and truth full reporting, is being cast aside in favor of public relations myths.

Sources

1.Smith,K. and Nicolas,A. “Recombination at work for meiosis” 1998 Current Opinion in Genetics and Development 8,200-11

2.Ray,A. and Langer,M. “Homologous recombination :ends as the means” 2002 Trends in Plant Sciences 7,435-41

3. Hanin,M. and Paszkowsky,J. “Plant genome modification by homologous recombination” 2003 Current Opinion in Plant Biology 6, 157-62

4. Cummins,J. “Regulatory sham on Bt-crops” 2003 http://www.i-sis.org.uk/RSOBTC.php pp1-4

5. US Environmental Protection Agency “Glyphosate oxidoreductase and the genetic material necessary for its production in all plants :Exemption from tolerance in all raw agricultural commodities” 1997 Federal Register 62,52505-9