Thursday, 15 March, 2001
Genetically modified foods ("Frankenfoods") have received a lot of bad press in the last few years. Some of the negative coverage is deserved, to be sure, but a lot of it is simply ill-informed reaction to new technology. The Friends of the Earth's "Real Food" page is fairly typical, although somewhat calmer than most. This FOE page brings up some valid points about chemical farming and the need for more rigorous testing of new plant strains for allergic reactions, but their concerns about cross pollination creating "super weeds" are wholly unfounded.
Humans have been performing genetic modification on food crops (often unintentionally) since the dawn of agriculture over 10,000 years ago. Early cereal grains were selected (probably unintentionally) for thinly coated seeds that germinate quickly, and a genetic mutation that prevents the stalk from shattering; leaving the seeds on the stalks rather than allowing them to fall to the ground and germinate. Early domestic peas were selected (again, unintentionally) for a similar mutation that prevents the pods from exploding and casting the seeds to the ground. Wild berries (strawberries, for example) are much smaller than the domestic varieties. Again, humans selected the genetic mutation to obtain plants that produce the larger fruits. All seedless plant varieties (bananas, oranges, grapes, watermelons, pineapples, etc.) are again genetic mutations that we have propagated over the centuries. Wild almonds are very bitter and quite poisonous, except those produced by trees that contain a gene mutation which prevents it from synthesizing the chemical responsible for the bitterness (amygdalin, which breaks down to yield cyanide). Early farmers discovered the non-bitter almonds from those trees and planted some. None of these genetic mutations could survive in the wild because they affect the plants' ability to reproduce. Agriculture is full of similar examples. Very few domesticated plant varieties would survive for long in the wild.
If you doubt the power of selecting for genetic mutation, consider that modern cabbage, kale, kohlrabi, brussels sprouts, cauliflower, and broccoli all share a common ancestor. They are the same plant! The different varieties are the result of repeatedly selecting a domesticated wild cabbage plant for different attributes (leaves, stems, buds, and flower shoots). Or consider that modern corn is so completely different from anything found in the wild that the question of its wild ancestor is hotly debated. The time to produce a new variety depends on the extent of the mutation. You can turn a cabbage into a cauliflower in a relatively few generations. Modern corn, on the other hand, evolved over thousands of years.
Although cross pollination is known to occur between varieties of the same species (pumpkins and gourds, for example, or among different types of squashes), cross-pollination between species is not possible. Suggesting that a genetically modified soybean that resists a particular chemical herbicide could cross with a dandelion to create a "super weed" is just uninformed alarmism.