The world according to Monsanto : pollution, corruption, and

the invention of gmos 137nomic procedure cannot be identified with the techniques of genetic manipulation,which, rather than respecting the natural laws of plant development,attempt instead to break them in any way possible.Molecular biologists knew very well that plant organisms possess defensemechanisms designed to protect them from the intrusion of foreign bodies,including, of course, genes coming from other living species. From the verybeginning, those biologists understood that genetic manipulation could notbe carried out without using an intermediary, or a “mule,” able to transportthe selected gene and make it enter by force into the target cell. For this purpose,they turned to a bacterium that is abundant in the soil, Agrobacteriumtumefaciens, which has the capacity to insert some of its genes into plantcells to cause tumors.* In other words, this bacterium is a pathogen thatchanges the genetic inheritance of cells by infecting them.In 1974, a Belgian research team succeeded in identifying the plasmid (aring of DNA) constituting the vector by which the gene that induces the tumoris transferred from the bacterium to the plant. In St. Louis, as in laboratoriesaround the world at the time, they then attempted to isolate in theplasmid the gene responsible for the tumors and replace it with the gene ofinterest by adding a gene “promoter,” a sequence of DNA that triggers theexpression of the gene to be triggered. The gene in question is often 35S,from the cauliflower mosaic virus, which is related to the hepatitis B virus,raising the alarm of some opponents of unrestricted tinkering with genes.But there was more: if the gene-inducing tumors had been suppressed,how could one know that the plasmid was doing its work and inserting thesubstitute gene in the plant cell? The only solution the sorcerer’s apprenticesfound was to attach to the genetic construction what they called a“selection marker,” in this case a gene resistant to antibiotics, usuallykanamycin. To verify that the transfer had actually taken place, the cellswere sprayed with an antibiotic solution, and the “chosen” were those thatsurvived this shock treatment. (This gave rise to further health concerns—at a time when resistance to antibiotics was in the process of becoming a seriouspublic health problem, some Cassandras were afraid that the selectionmarker would be absorbed by bacteria populating the human intestinaltract, reducing medicine’s ability to fight infectious agents.)*Agrobacterium tumefaciens causes crown gall disease, which attacks the roots of some plants by inducingthe growth of a tumor. It was discovered by two American researchers in 1907.