Transgenic plant technique acts with pin-point precision

After decades of searching, plant biologists have found a way to selectively snip out one gene and replace it with another. The method promises to be a boon to both basic research and the creation of genetically engineered crops, observers report in the journal Nature: 29 April 2009.

An argument continually raised as a concern about GM crops, and one that is largely true, is that in creating a transgenic plant, scientists have minimal, if any, control over where the foreign gene inserts itself in the plant.  The concern is that this insertion point might disrupt the function of existing genes in unknown ways, ways that might be detrimental to human health or the environment.  This is true, but what is rarely mentioned is that scientists, in Australia at least, must then show government regulators the gene sequence within the plant where the foreign gene has been inserted and that it is stable over a number of generations.  So they may be unable to control where the gene inserts, but they can certainly find it after the fact and therefore know if it is in a position that could affect the function of other genes.  What those upset functions might be become clear during laboratory growth trials.

But this new technique might overcome this hurdle, but will it have any effect on the attitude of those opposed to GM crops – at least those aware that this aspect of transgenic technology is a concern? 

See the GNTIS link in the news section for more of the story or contact the GNTIS for a copy of the full story or published scientific papers. Briefly, though, the following excerpt from Nature states that the technique relies on enzymes called zinc-finger nucleases, which bind to specific sites in a genome and then cut nearby strands of DNA. When the cell repairs the cut DNA, the gap can be either simply sealed — in effect deleting the targeted gene — or filled in with a new gene. Zinc-finger nucleases have recently been used to create human immune cells that are resistant to HIV.

My suspicion is that nearly all people outside of plant breeding research will be unaware that this is one of the key arguments in the debate over GM crops and that this will not have any influence on the debate whatsoever largely because the debate has become more grounded around social, cultural and political issues than anything scientific.  But I am prepared to be corrected, should anyone have any thoughts on this.

Jason Major

Manager, GNTIS