I am not by any stretch of the imagination an expert in these matters, but I believe the evidence presented below shows that genetically modified organisms have and will cross with non GM crops and wild relatives. This will make it impossible to have any foods that will be free of the modified genes, and any other dangerous bits and pieces that have been inserted into the organisms.

Other evidence shows that the vectors used are also dangerous, and this means that the whole process must be stopped until such time as the scientists themselves (free of the constraints imposed on them by greedy self-interested corporations) can prove conclusively that they have reached a level of expertise and knowledge that is needed to be sure of no danger.

What appears below is not speculation to be argued about politely with the representatives of corporations, but things that have actually happened.

GMOs Cannot Be Kept Apart From their Wild and Cultivated Relatives
Transfer of Gene to Non-GMO Crops

Field tests with genetically engineered potatoes have demonstrated both the high frequency and wide range of gene flow. When normal potato plants were planted in distances up to 1100 metres from genetically engineered potatoes, and the seeds of the normal postatoes were collected afterwards, 72% of the plants in the immediate neighbourhood of the transgenic potatoes contained the transgene. At greater distances an almost constant 35% of seeds contained the transgene (Skogsmyr I (1994) Gene dispersal from transgenic potatoes to conspecifics: A field trial. Theor. Appl. Genet 88:770-774.)

Scientists at the Scottish Crop Research Institute have shown that much more pollen escapes from large fields of genetically engineered oilseed rape than is predicted from earlier experiments on smaller plots. They found that escaping pollen fertilised plants up to 2.5 kilometres away (Timmons AM, O'Brien BT, Charters YM & Wilkinson MJ (1994) Aspects of environmental risk assessment for genetically modified plants with special reference to oilseed rape. Scottish Crop Research Institute, Annual Report 1994, SCRI, Invergowrie, Dundee, Scotland.).

Transfer via Human Systems

Crop seeds travel hundreds of kilometres between seed merchant, farmer and processing factory, therefore spillage in transport is inevitable - and could be more worrying than threat through pollen spread (Crawley M (1996) 'The day of the triffids', New Scientist 6 July pp40-41 - this was further referenced).

Transfer of Foreign Genes to Micro-Organisms

It was reported in 1994 that gene transfer can occur from plants to micro-organisms. Genetically engineered oilseed rape, black mustard, thorn-apple and sweet peas all containing an antibiotic-resistance gene were grown together with the fungus Aspergillus niger or their leaves were added to the soil. The fungus was shown to have incorporated the antibiotic-resistance gene in all co-culture experiments (Hoffman T, Golz C & Schieder O (1994) Foreign DNA sequences are received by a wild-type strain of Aspergillus niger after co-culture with transgenic higher plants. Curr. Genet. 27: 70-76.). It is worth noting that micro-organisms can transfer genes through several mechanisms to other unrelated micro-organisms.

Unexpected Effects

Genetically engineered soil bacteria Klebsiella: A common harmless variety of a bacteria Klebsiella planticola, inhabiting the root-zone of plants had been genetically engineered to transform plant residues like leaves into ethanol that farmers could readily use as a fuel. The genetically engineered bacteria not only survived and competed successfully with their parent strain in different soil types, it proved unexpectedly to inhibit growth or kill off grass in different soil types tested. In sandy soil, most of the grasses died from alcohol poisoning. In all soil types the population of beneficial mycorrhizal fungi in the soil decreased. These soil fungi are crucial for plant health and growth as they help plants to take up nutritions and to resist common diseases. In clay soils, the genetically engineered bacteria increased as well the number of root-feeding nematodes. (Holmes T M & Ingham ER (1995) The effects of genetically engineered microorganisms on soil foodwebs, in "Supplement to Bulletin of Ecological Society of America" 75/2).

The bacteria Pseudomonas putida was genetically engineered to degrade the herbicide 2,4-D. The engineered bacteria broke down the herbicide but degraded it to a substance that was highly toxic to fungi. These fungi - crucial to soil fertility and in protecting plants against diseases - were therefore destroyed (Doyle JD, Stotzky G, McClung G & Hendricks CW (1995) Effects of Genetically Engineered Microorganisms on Microbial Populations and Processes in Natural Habitats, Advances in Applied Microbiology, Vol 40 (Academic Press)).

The toxin-producing gene of the bacteria Bacillus thurigiensis, for instance, is commonly engineered into crops to provide them with a built-in insecticide. However, the toxin produced is known to resist degradation by binding itself to small soil particles whilst continuing its toxic activity. The long term impact of this toxin on soil organisms and soil fertility is unknown (summarised in Doyle et al 1995).