TRANSGENIC FOODS: PROMISE OR PERIL?

• Author: Acosta, Anne

The topic of transgenic food may be the most controversial area of scientific research since the advent of nuclear power. Like nuclear power, transgenic food offers great promise to address one of humankind's basic needs, in this case by potentially increasing the world's food supply. But also like nuclear power, transgenic food raises fears in many people's minds--about safety, about monopoly control over something as important as our daily bread, and about where all these scientific possibilities are taking the human race. There are a number of scientific-technical issues that "experts" argue about, but there are also emotional debates that circle around whether the public can trust science and business to behave with the world's best interests in mind. And the issues are also different if you're a farmer in Guatemala or Cuzco, or a consumer in Buenos Aires or Montreal.

What exactly is everyone so excited about, or so afraid of?. It helps to start with a quick history of mankind's tinkering with biology (actually, it has been "woman"kind at least as much as "man"-kind, since throughout history women have often been the seed-savers). Farmers have been changing the genetic composition of plants for more than ten thousand years, most often by choosing the seed from theft best plants to grow again the following year, and sometimes by choosing to cultivate naturally occurring mutations of theft normal crops. In this way, all the world's major cultivated species, including maize, have become significantly "genetically modified" from their prehistoric form.

In the last one hundred years or so, the science of plant breeding has sped up the process of improving plants for human purposes, usually to achieve higher yields, and often also to increase plants' tolerance to insects, diseases, drought, and poor soil conditions. But this "conventional" approach to plant breeding can still be very time consuming. The desirable trait first has to be found in a related plant type, then bred over a number of years so that only that trait is passed on in a variety that farmers prefer. For example, a kind of maize may be identified in Mexico that is resistant to a disease common in Brazil, but the Mexican maize is also very different in taste and other qualities from that grown by Brazilian farmers. It may take six to ten crop cycles to breed in and fix the new trait in the Brazilian maize, screening out the other unwanted new characteristics and protecting what was best about the original Brazilian variety. Doing plant breeding like this is like trying to color in a fine etching with a paint roller, and with only a few colors since one can't always find the desired trait in the palette of known related varieties.

Keeping the same analogy, biotechnology offers the possibility of a much larger range of hues, which can be applied with increasingly pinpointed accuracy. Advances over the last twenty years in our understanding of genetics are allowing scientists to find specific genes that can be moved from one species to another and between viruses, bacteria, plants, and animals to produce significant changes in the host species. This is a major change from conventional breeding in three ways: It allows the transfer of genes between organisms that would never cross-breed; it allows the transfer of only those genes that produce the desired outcome; and it takes plant breeding out of the field and puts it into a laboratory. And in each of these dimensions lies promise and peril.

On the positive side, one can imagine (and in fact, scientists are already on the path to creating) plants that have genetic resistance to insect pests and diseases--thus greatly reducing the need for chemical means to control these plagues ("Bt" maize is one of the first successful efforts in this regard). Under conditions of "modern" agriculture, this holds out the benefit of less environmental contamination. Of equal importance, for resource-poor farmers in developing countries unable to buy inputs to protect their crops...