Horizontal Gene Transfer Happens.

• Author: Ho, Dr. Mae-Wan

A Practical Exercise in How Scientific Evidence Must be Interpreted and Used in Accordance with the Precautionary Principle and Sound Science

[Horizontal gene transfer is the transfer of genetic material between organisms and even species. Bacteria do this naturally. Genetic engineering increases the variety of DNA which is available for bacteria to transfer. Critics of the biotechnology industry contend that once genetically modified plants and animals are released into the environment bacteria and viruses can accelerate horizontal gene transfer and pass on harmful traits. Disease-bearing bacteria could pick up resistance to antibiotic drugs; crops modified with genes that kill common pests or make the crops immune to herbicides could have these traits passed on to less desirable plants, giving rise to "superweeds." Biotech supporters say this risk is unproved and exaggerated. Biologist Mae-wan Ho examines the evidence. --Henry Robertson]

At first, they said horizontal transfer of genes to unrelated species couldn't happen; then they said "just because it happens in the laboratory doesn't mean it happens in nature." Recently, Prof. Katz of Jena University found in field studies that genetically modified (GM) genes may have transferred from GM pollen to bacteria and yeast in the gut of baby bees (The Observer, May 28, 2000).

But, researchers earlier found evidence of horizontal transfer of GM genes to soil bacteria in the field where GM sugar beet was planted, and this has been reported in the scientific literature. [1] Readers of ISIS News will note that there have already been several studies documenting the horizontal transfer of GM genes from GM plants to soil fungi and bacteria in the laboratory. [2]

In this article, I shall review a published study to show how the precautionary principle can be applied in practice to interpret and use scientific evidence responsibly and in accordance with sound science. German geneticists Frank Gebhard and Kornelia Smalla began a series of experiments in 1993 to monitor field releases of GM rizomania-resistant sugar beet (Beta vulgaris) for persistence of the GM construct in the soil and for horizontal gene transfer. They found that the GM construct persisted in the soil for at least two years after the plants were grown and harvested, and different parts of the GM construct may have transferred to unknown soil bacteria. The researchers are exemplary in documenting clearly their experimental material...