Gene-splicing and other methods of modifying plants

Some radical environmentalists want to ban gene-spliced organisms, but they have not proposed the same for organisms genetically modified by older methods, say experts.

Gene-splicing involves the introduction or substitution of just a few genes whose locations and functions are known. It is more precise and predictable than older, less exact methods used to change plant characteristics, according to the U.S. National Research Council.

Furthermore, gene-splicing is heavily regulated by the U.S. government, while each year dozens of new plant varieties produced through traditional methods are marketed without any scientific review or special labelling.

One of those methods, called hybridisation, can involve crosses between plants of different species or even genera.

Thus the relatively new manmade “species" Triticum agropyrotriticum, cultivated for food, is a hybrid of common wheat and a weed called quackgrass.

It has all of wheat's chromosomes plus an entire genome of quackgrass – introducing thousands of extra genes into a widespread plant variety.

Another technique is "induced-mutation breeding."

In widespread use since the 1950s, it involves subjecting cultivated plants or their seeds to ionising radiation or toxic chemicals to induce random mutations.

Most mutations kill the organism – but sometimes a plant that survives exhibits a desirable new trait.

Although no one knows which genes have mutated to produce the new traits – or what other mutations might have occurred – 1,400 varieties of plants produced by induced mutation have been marketed in the last half-century.

Plants of several of these varieties – including two of squash and one variety of potato – were banned because they contained endogenous toxins at dangerous levels.

There is minimal risk from such plants, and less from gene-spliced plants. Yet U.S. Department of Agriculture requirements make paperwork and field trials for gene-spliced organisms 10 to 20 times more expensive than for plants modified in other ways.

Source: Henry I. Miller (Hoover Institution) and Gregory Conko (Competitive Enterprise Institute), Precaution (of a Sort) Without Principle, Priorities for Health, Volume 13, No. 3, 2001, American Council on Science and Health.

For text http://www.acsh.org/publications/priorities/1303/coverstory.html
For more on Biotechnology & the Environment http://www.ncpa.org/iss/env/

FMF Policy Bulletin\6 November 2001