Genetically engineered food – antibiotic-resistance markers
When gene engineers splice a foreign protein into a food product, they most often link it to another gene, called an antibiotic-resistance marker (ARM) gene. By dousing this new genetically engineered creation with an antibiotic, the genetic engineer can tell whether the gene-splicing procedure has been successful. Basically, if the antibiotic does not kill the gene-food, then the splicing has been successful because the inserted antibiotic-resistant marker gene provides protection. Although this sounds quite clever, there is a down side to ARM-ing genes.
Scientists and public health officials worry that ARM genes employed in gene-spliced foods or animal feeds might “mate” or combine with an expanded range of pre-existing germs or pathogens to give rise–deadly new strains of antibiotic-resistant “superbugs” (Salmonella, Echerichia coli, Campylobacter, Staphylococcus, Myco-bacterium tuberculosis, and enterococcus).
It is possible that ARMed genes might be contributing factors to the growing public health problem of infections that cannot be cured with ampicillin, kanamycin, penicillin, or other traditional antibiotics. This phenomenon of inadvertently transferring antibiotic resistance into non-target organisms or pathogens is a prime example of horizontal gene transfer–an extremely rare occurrence in nature until the advent of genetic engineering. Geneticists call this type of unnatural genetic transmission “horizontal gene transfer” to differentiate it from the normal vertical gene transfer, which occurs when nongenetically engineered living organisms pass their genes and genetic characteristics on to their offspring.
Dutch scientists have found, in a sophisticated computer simulation of the human digestive system, that ARM genes in genetically engineered food can recombine with bacteria already present in the human gut to give rise to new bacterial strains.
“The results show that DNA lingers in the intestine and confirm that genetically modified bacteria can transfer their antibiotic resistance genes to bacteria in the gut,” they reported in New Scientist magazine.
In another study, British scientists found that ARMs and other transgenic deoxyribonucleic acid (DNA) can recombine with bacteria in the human mouth and throat for up to an hour after being ingested, thereby giving rise to new strains of bacteria.
Given the emerging science on ARMs, it comes as no surprise that the respected British Medical Association in 1999 recommended that the use of antibiotic-resistant marker genes “should be phased out as swiftly as possible.” European authorities are currently considering a ban on all genetically) engineered foods containing antibiotic-resistant marker genes as well as a ban on antibiotics added to animal feeds.
Modified with permission. Genetically Engineered Food [c]2000 by Ronnie Cummins and Ben Lilliston. Published by Marlowe and Company. $12.95. (To order this book, call: 1-800-266-5766, ext. 1802, or visit clicksmart.com/nutrition.)
COPYRIGHT 2002 Vegetus Publications
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