What the GMO technology bringing about

 

Masaharu Kawata

(Division of Biological Science, School of Science, Nagoya University)

 

 Amounting facts and fears about the dangers of technology are now challenging the myth that GMO can feed the expected population explosion of the future world.  The article entitled "Evidence of the Magnitude and Consequences of the Roundup Ready Soybean Yield Drag from University Based Varietal Trials in 1998" was published by Dr. Charles Benbrook July 1999 in USA.  It summarizes yield performance tests carried out in over forty places in eight states in the USA  (Illinois, Iowa, Michigan, Minnesota, Nebraska, Ohio, South Dakota, Wisconsin) in 1998 on herbicide tolerant soybeans developed by Monsanto, the biggest GMO company in the world.

 

 The researchers of the eight state universities compared yields of many strains of Roundup Ready Soybeans and their sister strains not bio-engineered in various geological conditions. This is the most impartial data available to date.  The results were unexpected and surprising .  Almost all data showed that the yields of Round up Ready strains are about six percent on average less than those of the original conventional sister strain.  The herbicide tolerant gene from soil bacteria inserted into the genome of soybean results in a disadvantage to farmers and consumers. Only the Monsanto would get profit from the genetically modified crops because farmers have to buy expensive seeds and the herbicide together.  In fact, about 60 % of the Soybean planted in USA in 1999 was Roundup Ready, and 54% of the herbicides used in USA in 1999 contained glyphosate, the active ingredient of the Roundup herbicide of Monsanto Co. This market domination by Monsanto arose in 1996 when they began to put the genetically engineered crops on the market.

 Consumers also suffer from the Roundup Ready Soybean, because the regulatory standard of the residues of glyphosate in soybean was elevated suddenly to 20 ppm from the former 6 ppm this April in Japan due to political pressure by the US government and Monsanto.  The US would not able to export these Soybeans if the regulatory standards of foreign countries were

not changed. 

 Our fears became realized when Dr. L.Hardel and Dr.M.Eriksson of Sweden reported a study showing that the herbicide glyphosate can cause a cancer, Non-Hodgkin's lymphoma, in the Journal of the American Cancer Society (Cancer, vol85, p1353, March 1999).  This dangerous liberalization of the regulatory standards will affect not only Japan, but all countries which import American soybeans.

 The report by Dr. Benbrook gives a warning on the future of US agriculture that the amount of agrochemical usage is increasing in the USA by adopting Roundup Ready Soybean in opposition to the argument by Monsanto and scientists promoting GMO.  The extensive use of a single herbicide like Roundup in the field would facilitate the appearance of tolerant weeds, which in consequence would make farmers lose the means of suitable weed management in the USA.  These worrying symptoms have already been caused in Canada in 1999.  Mr. Tony Huether, a farmer of Alberta, Canada, planted three kinds of herbicide resistant canola species containing Roundup Ready in 1997 in his field.  After two years, a doubly resistant weed appeared, and after three years super-weeds, tolerant to all three herbicides, emerged (reported by Mary MacArther, Camrose bureau, February 10, 2000).  The possibility was discussed two years ago by American scientist Dr. Joy Bergelson as gene flow from bio-engineered crops to weeds by pollination (Nature, September 3 1998). 

 No good yields of Roundup Ready Soybean and Bt corn that carry insecticidal genes

have been reported by other research in the USA in these two years.  The GMO may not only not help to increase future food supply, but also impose serious impacts on the environment and conventional agriculture.

 

 The most radical and important problem of the genetic engineering of plants lies in the technical difficulty of determining the location for foreign gene insertion in the host genome.  To this day no means, whether using Agrobacterium T-DNA, chemical or electrical poring of the cell membrane, can locate the exact insertion site.   The random insertion of a foreign gene will affect various domestic gene activities, as inactivation of structural genes, promoters or enhancer sequences, causing metabolic influences in the host cell.  The yield drag of the RR soybeans may be an example of the effect, an agronomist of Nebraska University Roger Elmore says (IANR News Service, University of Nebraska) after his two-year study.  Another example of metabolic change by inserting a glyphosate tolerant gene into a conventional soybean strain is increased heat sensitivity of the RR soybean (W.K. Vencil et al, Brighton Conference of British Crop Protection Council, 20 November 1999).  The stem cracked almost 100 % when the soil temperature rose to more than 45.  One result may be the  over-production of Lignin in the RR soybean compared with the conventional strain by the insertion of a foreign gene.  Then the RR strain may not be suitable for growing in hot areas like countries in the south.

 The second problem of this technology is changes to and instability of the nucleotide sequence, rearrangement of the inserted DNA sequence in the host genome during gene engineering. It may cause unexpected results such as the production of allergy proteins or other toxic substances.  In this regard, Monsanto announced on 13 May 2000 that they found two rogue DNA fragments in the Roundup Ready Soybean genome in addition to the CP4EPSPS gene that they insisted was the only gene inserted into the soybean gene since 1992 when the process was approved in the USA.  The DNA fragments are contained in all strains of Roundup Ready Soybeans that Monsanto has ever distributed, but "no actual harmful effects have been reported" according to Monsanto.  However, this statement itself demonstrates the uncertainty of gene engineering.  In England reported concern has been a 50% increase in the incidence of soybean allergies in the past year, and the increased imports of the GM soybeans is suspected (Dairy Express, 12 March 1999).

 Uncertainty may also come from recombination between prokaryotic and eukaryotic genes that does not normally occur in nature.  The genetic code translation systems differ a little between organisms.  Then, some amino acids in the product proteins may be altered from the presumed DNA sequence of original organism.  Such a case was reported for human insulin-like growth hormone produced in Echerichia coli, in which the original Arginine code in human protein was translated into Lysine in E.coli cell (R. Seetharam et al, BBRC., vol. 155,p518, 1988).  This experiment was reported by researchers of Monsanto Institute.

 The third problem of GMO technology may be the presence of an unnecessary gene of antibiotic resistant trait from E.coli plasmid in the inserting vehicle plasmid.  This is required for multiplication of the foreign gene in E.coli, and for selection of the recombined plant cells from many untransformed residual cells which are killed by antibiotics in the test tube before planting in the field.  This technique is necessary to  facilitate the efficiency of the process  but is entirely unnecessary to the transformed plant and dangerous to the humans and animals that consume the product.  The corn or potatoes we have to eat everyday then carry the antibiotic resistance gene and its products. Such food is antibiotic tolerant.  It may cause serious effects when we need antibiotics to cure disease.  A German entomologist, Professor H.H.Kaatz found herbicide tolerant enterobacterium and yeast in the digestive tract of honeybees that were fed pollen of herbicide tolerant canola (The Guardian May 29, 2000).  This suggests that the enterobacterium of human and livestock can develop antibiotic tolerant or herbicide- resistant properties by eating GMO foods. 

 

 The environmental impacts of genetically engineered plants have been demonstrated by many such examples during these three years.  Most impressive study was reported by the researchers of Cornel University, USA, last year, who found lethal effects of Bt corn pollen (carrying an insecticidal gene) on larvae of non-targeted butterfly, Monarch which is a very common insect in Northern USA (Nature, vol399, p214, 20 May 2000). Some other groups also confirmed these facts.  This unexpected effect will decrease the biological diversity in future, considering the vast planting areas of such crops in the world.  Another interesting study is that of Dr. Joy Bergelson (Nature, September 3 1998).  She had created two kind of mutant plants of Arabidopsis thaliana, frequently used for plant genetics. One is a chemically induced mutant, resistant to the herbicide chlorsulphuron in which an enzyme acetolactate synthase (Csr1-1) is mutated. She then isolated the gene and inserted it in the wild strain by genetic engineering. Two bio-engineered strains were isolated, both of which are herbicide resistant like the original mutant.  These herbicide tolerant strains were planted together with the sensitive wild strain in a field.  Abnormal fertility was observed when she collected and analyzed the herbicide resistant seeds (100000 pieces) from the wild plant. The pollinated seeds by mutant and transgenic males were compared.  The male genes came from chemically induced mutant fathers (0.3 %) and transgenic fathers (5.98%).   Usually the Arabidopsis thaliana is self-pollinating. However the experiment clearly shows that the transgenic plant dramatically increased its outcrossing rates, 20 times that of the induced mutant.  This fact itself means that genetic engineering is radically different from the natural mutation or natural gene exchange (homologous recombination) that has long been used in breeding plants and animals.  In addition, this warns that a gene flow from transgenic crops will occur to weeds, by which the potential usefulness of agrochemicals might be lost. 

 

 The genetic engineering of crops interfere with evolution by jumping the walls between biological species.  Nature does not ordinarily permit the mixing of genes from very different species, genus or families.  However genetic engineering easily recombines easily their genes.  Both the Roundup Ready gene and Bt gene (insecticidal gene) are dissected from soil bacteria and inserted into bean and corn plants.  The gene escape from these crops will change the genetic composition of weeds and similar genus of wild plants.  A reverse example was found  when an antibiotic- resistant gene was transferred from a sugar beet plant to soil bacteria. 

Biological diversity changes are now occurring due to artificial technology and human requirements, not by the process of natural selection that developed the biological world on  earth.  We do not know yet what problems artificial gene exchange by gene technology will bring about. 

 

 

Back