By now we're aware of the increasing amounts of genetically engineered (GE) foods on grocery store shelves. But we're still ignorant about what this means for our future food supply and healt.
By now we're aware of the increasing amounts of genetically engineered (GE) foods on grocery store shelves. But we're still ignorant about what this means for our future food supply and health. Do new gene constructs have the ability to affect the environment, or even human deoxyribonucleic acid (DNA) the genetic material of nearly all living organisms?
Because of genetic tampering of our food we ingest large amounts of degraded DNA in our normal diets. Researchers have told us that consumed DNA is unlikely to survive intact beyond the stomach, although other studies have proven that fragments may enter the bloodstream and even attach themselves to cellular DNA. Because of the small size of these fragments it was believed that they wouldn't be able to affect animals.
Lately scientists are finding this not to be the case. There's a strong argument for the transfer of genes from one species to another otherwise known as "horizontal gene transfer." If this is true, then genetic material from plants could insert itself into the DNA of other species, potentially even humans.
Michael Syvanen, professor of medical microbiology and immunology at the University of California, Davis, has been studying transgenics for years. According to Syvanen, gene transfer is involved in evolutionary change. He, along with other researchers, has found evidence that significant quantities of DNA can survive passage through a mouse's digestive system, staying intact for much longer than originally thought possible. Syvanen claims that although this type of gene transmission hasn't been found in nature yet, there is enough laboratory evidence to warrant concern, particularly with increasing transgenic food developments.
This transfer of genes or genetic material directly from one organism to another occurs by a process similar to infection. It differs from the normal gene transfer between parent and offspring because it can occur randomly, between different species. This means that genes can be spliced between species that would never naturally interbreed. For example, toad genes can be transferred to potatoes, fish genes to fruit.
Genetic engineers are using this developing technology to create plants that are hardier than traditional crops and yield fruit that have more consumer-desirable qualities. However, the insertion of foreign genomes into the host structure is not entirely under the control of the genetic engineer! Scientists cannot predict the exact point at which the new gene will insert itself into the host DNA. This gives transgenics a random effect, which critics say may be responsible for unintended results like the production of toxins and allergens in food.
Liberated Genes Cause Problems
According to Dr Mae-Wan Ho, scientific advisor to the Third World Network, recent evidence shows that genetic material can be released from transgenic plants to the surrounding environment. Transference to the surrounding soil may occur as the plant decomposes or may simply exude from the plant's roots.
Disturbing consequences of horizontal gene transfer include the potential for antibiotic resistance, the generation of new viruses and reactivation of dormant viruses that cause disease. Even more disturbing is the possibility of horizontal transfer from genetically engineered food to animal and human DNA. Critics say that such genetic transfer could lead to the reactivation of dormant viruses or the incorporation of other pathogens into the human system.
Dr Ho stresses that the only reason that there is no direct evidence that latent viruses can be reactivated in plants and humans is because the possibility has not yet been investigated. However, there is evidence that genes introduced into plants behave differently than the plant's own. These foreign genes are up to 30 times more likely to escape and spread than the plant's own genes. This may happen as simply and naturally as insects visiting plants for pollen and nectar!