There is nothing sinister or alien about genetically modified crops. They already happen in nature.by Conrad Lichtenstein / July 20, 1999 / Leave a comment
So, the british Medical Association, and virtually everyone else, has joined the lobby against genetically modified (GM) food. GM maize harms monarch butterflies in the American cornbelt. Our sexuality is under threat from oestrogen-mimics produced in GM soya beans sprayed with herbicide. We feel bullied by big business and suspect government collusion in GM food release without proper safety trials. We fear threats to the ecosystem, the food chain and human health. We fear the escape of foreign genes into the wild. We fear an alien and unnatural technology.
Yet genetic modification is not unnatural: indeed, for those of us still old-fashioned enough to smoke, every time we puff on a ciggie, we inhale the combustion products of a natural GM event which took place millions of years ago somewhere in the Andes. At Queen Mary and Westfield College, University of London, Andrew Leitch and I are studying the evolutionary origin of viral gene fragments we discovered in tobacco and four of its relatives. How did this ancient genetic “accident” happen? Why has it perpetuated during evolution? Answers to these questions may also help to assess artificial GM escapes into the wild.
Genes are handed on from parents to offspring and during this “vertical transmission,” natural genetic changes (mutations) result in variation in the offspring. Natural selection for the more successful variants results in the formation of new species. This is evolution as Charles Darwin presented it, with the added spice of genes from Gregor Mendel plus our modern understanding of both DNA, as the physical embodiment of genetic information, and of how mutations occur.
Language also changes during “vertical transmission,” for example, from Chaucer’s to Shakespeare’s to our modern English. But just as English has acquired and assimilated foreign words -“robot” from Czech, “pundit” from Hindi, “guerrilla” from Spanish-so organisms can acquire foreign genes from other species, a process known as “horizontal transmission.”
Horizontal gene transfer happens frequently in nature. For example, soil bacteria produce antibiotics for waging chemical warfare upon their competitors. Antibiotic-resistance genes, which equip these bacteria with antidotes against their own toxins, are transferred naturally from these warmongers to other bacteria, including human and animal bacterial pathogens. So, when antibiotics are used by doctors to treat bacterial infection those pathogens which have naturally acquired these resistance genes can, alas, survive.
Horizontal transmission can also be exploited artificially for our benefit. For example, it can equip…