Your News story “Synthetic biologists face up to security issues” (Nature 436, 894–895; 2005), defines synthetic biology as the ability “to create complete genomes from scratch and to introduce new characteristics into viruses and bacteria”. But the second half of this definition has already been applied for decades to genetically modified organisms (GMOs), and particularly to modified viral genomes. The present discussion about regulation of synthetic biology should carefully consider how and why GMOs are regulated, in order to avoid regulatory chaos.

The US and Canadian systems for GMO regulation are based on the properties of the organisms produced, whereas the European system is based more on techniques. The incompatibility between product-based and technique-based systems is the source of much of the transatlantic tension regarding GMOs.

North American scientists are calling for technique-based regulation of synthetic biology. But for products of synthetic biology that bear novel genes and thus are also GMOs, which type of regulation should prevail: technique- or product-based? If the former, one would quickly encounter the situation where equivalent organisms, synthetic or classic GM, would be regulated using drastically different strategies and criteria. If the latter, the most potentially dangerous products of synthetic biology would simply be regulated as GMOs. If the United States and/or Canada go forward with technique-based regulation of synthetic biology, a minimum of coherence would require them also to shift to technique-based regulation of GMOs — a major policy change.

I believe that the first step to reassure the public about synthetic biology should be to cool the rhetoric. The present situation is reminiscent of 30 years ago, when some of the pioneers in the then-new field of genetic engineering made unrealistic claims about what was feasible; this was one of the major early sources of public uneasiness about GMOs. There should be a bit more modesty in claims both about what can be achieved by synthetic biology in the foreseeable future, and about what could be achieved by additional regulatory supervision.