Crop genetics Reducing transgene escape routes

Genetically modified crops and the food derived from them have had a bad press, but a rare piece of good news is provided by Daniell et al. in this month's Nature Biotechnology. They report a development that has profound implications for the risk assessment of genetically modified crops. Most crops are modified by inserting genes into the nucleus, and the genes can therefore spread to other crops or wild relatives by movement of pollen. By engineering tolerance to the herbicide glyphosate into the tobacco chloroplast genome, however, the authors have not only obtained high levels of transgene expression, but, because chloroplasts are inherited maternally in many species, they have also prevented transmission of the gene by pollen--closing a potential escape route for transgenes into the environment.