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[SANET-MG] synthetic genes and public relations
January 19, 2005
Prof. Joe Cummins
“Synthetic genes and public relations in crop biotechnology”
The promotion of genetically modified (GM) foods and crops has
profoundly impacted the reporting of scientific findings in both the
public news media and peer reviewed scientific journals. The foundation
of science has always the full and truthful reporting of scientific
observations and findings. Scientific reports that may imperil the
public relations proclamations of the corporate, government and
academic promoters of GM crops are either attacked groundlessly or
rejected for publication. The public relations picture promoted by
advocates has been that GM crops are a simple extension of plant
breeding and selection that has been carried on for thousands of years.
However, that fiction ignores the basic genetic facts that the existing
GM crops were produced by illegitimate recombination while traditional
plant breeding and selection was based solely on homologous (meiotic)
recombination that created the diversity driving natural selection.
Furthermore, the GM crops have been produced using synthetic
approximations of bacterial genes conferring resistance to herbicides or
insects while the gene products from the bacteria are used in the
final safety “testing” as surrogates of the proteins actually produced
in the GM crops. Public relations exaggerations are frequently used to
promote commercial products, what is new is that such exaggerations seem
to be replacing full and truthful reporting in peer reviewed journals of
science.
Essentially all of the current marketed GM crops involve use of
bacterial genes for insect or herbicide resistance. The bacterial genes
used are synthetic approximations of the bacterial genes. The synthetic
approximations are used because the bacterial genes function poorly in
plants due to the effect called codon bias. The synthetic approximation
genes are about 60% homologous with the bacterial genes but produce
proteins that are mainly homologous with the bacterial proteins (the
codon replacements differ in the wobble position , code letter
3).Nevertheless, amino acids are most frequently changed in the GM
plants to increase solubility in the plant environment. C terminal amino
acids are changed on the assumption that the changes do not effect
biological activity of the protein, but this is done without any real
control experiments.
In the “safety” approval of GM crops the protein products and
genes used in safety testing are taken from bacteria rather than crops.
Cooperative regulators agreed that the expense of purifying the products
from GM crops need not be incurred since thee products can be recovered
at little expense from liquid bacterial cultures. So none of the finally
safety tests have been done with the proteins and nucleic acid in GM crops!
The regulators argued that so long as the crop proteins had active sites
and epitopes characteristic of the bacterial protein they must be must
be equivalent. It is staggering that they have allowed exposure of
millions of humans to products that are not fully tested. Since the GM
foods are not labeled there is no way that the impacts can be resolved
in the population.
The regulators seem to presume that the synthetic DNA and
RNA produced are biologically inactive except for making protein. That
is, of course, a fully specious belief. There is the well known DNA
CpG trigger that activates innate immunity and induces inflammation. As
well the regulatory role of small RNA is becoming evident. It is easy to
find examples of DNA and RNA activities that are separate from their
role in bearing the genetic code. It seems to me even beginning
students would recognize that the actual synthetic genes and their
proteins need to be tested. Finally, it seems clear that the synthetic
genes have so little homology with the natural bacterial genes that they
have never faced the forces of natural selection they have only faced
the scrutiny of bureaucrats , which is truly cold comfort indeed!
As an example , the paper below proclaims that GM crops bearing
insecticidal proteins have been used for a number of years without
giving rise to resistant insects. The report deals with the refuge
strategy and the use of high toxin dosage along with pyramiding toxin
genes as factors preventing insect resistance from arising. However, the
main reason that insect resistance has not been detected was not
mentioned in the article. The main reason that insect resistance has not
appeared is that the US EPA allows the GM crop and refuge to be sprayed
with chemical insecticides. The refuge strategy of insect resistance
provides crop areas in which the target insect pest may thrive and breed
with resistant insects from the gm crop (insect genes for resistance
are usually recessive). Spraying chemical insecticides allows taking
damage free crops from the refuge but it also rubs out any resistant
insects. Another unmentioned factor that effects resistance is the use
of synthetic toxin genes in the various commercial gm crops that vary in
both toxin production and the actual sequence of the toxins. However,
that factor is far less imposing than the combination of GM crop toxin
and chemical insecticides. Nevertheless, frequently the tests for
insect resistance involve screening the resistant insects using
synthetic diets that incorporate the toxin proteins recovered from
bacteria not the actual toxin produced in the GM crop.
In Canada chemical insecticides have not been allowed in the refuge of
Bt crops until the upcoming growing season , but there does not appear
to have been any effort to screen for resistance in that country. Why
did the report ignore the use of chemical pesticides in combination with
refuge in gm crops? I think it may be related to the rise of public
relations in science publications. Traditionally, science reporting
demanded full and truthful reporting but with the paranoia of genetic
engineering those who report things not favoring public relations of GM
crops are punished severally.
Nature Biotechnology 23, 57 - 62 (2005)
Published online: 06 January 2005; | doi:10.1038/nbt1056
Insect resistance management in GM crops: past, present and future
Sarah L Bates, Jian-Zhou Zhao, Richard T Roush & Anthony M Shelton
“Transgenic plants expressing insecticidal proteins from the bacterium
Bacillus thuringiensis (Bt) were first commercialized in 1996 amid
concern from some scientists, regulators and environmentalists that the
widespread use of Bt crops would inevitably lead to resistance and the
loss of a ‘public good,’ specifically, the susceptibility of insect
pests to Bt proteins. Eight years later, Bt corn and cotton have been
grown on a cumulative area >80 million ha worldwide. Despite dire
predictions to the contrary, resistance to a Bt crop has yet to be
documented, suggesting that resistance management strategies have been
effective thus far. However, current strategies to delay resistance
remain far from ideal. Eight years without resistance provides a timely
opportunity for researchers, regulators and industry to reassess the
risk of resistance and the most effective strategies to preserve Bt and
other novel insect-resistant crops in development”
In conclusion, efforts should be made to keep the public, or at least
the science public, aware of the public relations subterfuge used in
promoting GM crops. Somehow, regulators need to be reminded that actual
GM products need to be tested.
.
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