Can crop transgenes be kept on a leash?

Debates about the benefits and risks of genetically modified (GM) crops need to acknowledge two realities: (1) the movement of transgenes beyond their intended destinations is a virtual certainty; and (2) it is unlikely that transgenes can be retracted once they have escaped. Transgenes escape via the movement of pollen and seeds, and this movement is facilitated by the growing number of incidents involving human error. Re-examination of our risk management policies and our assumptions about containment is essential as genes coding for pharmaceutical and industrial proteins are being inserted into the second generation of GM food crops. Even the best designed risk management can be foiled by human error, a reality that is underestimated by most GM crop-risk analyses. Thus, our evaluation of risk should assume that whatever transgene is being examined has a good chance of escaping.