Sir

Monsanto's decision to abandon ‘terminator’ technology has been welcomed by those concerned about the genetic modification of food crops. The public perception is that this technology would force farmers in the developing world to purchase expensive seed year after year from multinational conglomerates. Although this is an important consideration, such technology might also have beneficial consequences, because ensuring the sterility of genetically modified (GM) crops could offer an important mechanism for environmental containment. By genetically engineering sterility, one could ensure that GM plants could not spread or cross-pollinate with naturally occurring varieties.

The paradigm of sterility/incompetence is not new. The laboratory molecular biologist is all too familiar with containment, both at the physical and the biological level. In the 1970s there were fears that genetic engineering would result in the release of ‘horror pathogens’. These fears were countered by the engineering of replication-incompetent vectors and disabled host organisms unable to grow outside the lab. This principle has been extended to the situation where molecular biology is used to treat human disease — gene therapy — where ensuring replication incompetence of viruses has been an important regulatory hurdle for virally mediated gene transfer.

Concerns about cross-fertilization have featured frequently in the UK media, and have been countered mainly by arguments about physical distance, such as how far bees can fly. It is surprising that the lessons learned in applying molecular techniques to contain GM organisms in the lab have not been applied to agricultural biotechnology. Such features should be placed high on the agenda of policy-makers and those in industry trying to persuade us of the safety of their products. Although there are moral and social dilemmas surrounding ‘terminator’ technology, these techniques should not be discarded without further reflection.