Are Biotech Foods Safe?

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One difference between biotechnology and conventional plant breeding is that recombinant DNA methods permit breeders to move genes between wholly unrelated organisms, including organisms in different taxonomic kingdoms.  For example, a gene from a plant virus can be inserted into crop plants to make them immune to diseases caused by the virus – much like a human vaccination.  Or, a gene from a common soil bacterium that codes for a protein toxic to certain insects, but not to humans or other animals, can be inserted into plants to make them resistant to chewing pests.

DNA and genes work essentially the same way in all organisms, and there is a broad degree of similarity in the genetic makeup of organisms as widely varying as bacteria, viruses, insects, plants, and animals, including humans.  For example, up to 90 per cent of rat genes have matches in humans, and as many as 48 per cent of human genes associated with diseases can be found in the common wild plant Arabidopsis thaliana.  

It is the commonality of function that makes modern biotechnology possible.  But, that also makes it common for such inter-kingdom gene transfers to occur in nature.  The family of plant Mosaic viruses reproduce by inserting bits of RNA into plant cells, but sometimes these become disabled, and are taken up and incorporated into the plant’s genome.  A bacterium known as Agrobacterium tumefaciens causes crown gall disease in plants by inserting a small segment of its DNA into the plant’s cells, which then become incorporated at a more or less random location in the plant genome.  Since neither of these plant diseases is harmful to humans, infected plants often make it into the food supply, and we commonly consume millions of individual genes of viral and bacterial origin in every bite of broccoli, potato, squash, tomato, and countless other fruits and vegetables.

In fact, plant breeders first discovered how to use recombinant DNA in plants by using the natural process that A. tumefaciens provides.  They replaced the bacterium’s infectious genes with useful ones, and then let the modified A. tumefaciens naturally insert the target genes into plants.  Thus, there is nothing inherently novel about these kinds of inter-kingdom genetic transfers, and moving genes between species with biotechnology does not pose any unique risks.  As with plant breeding more generally, all that matters is the function of the particular gene that is transferred.