Synthetic organisms: threads not that new

Genya Dana and colleagues (Nature 483, 29; 2012) describe a scenario of synthetic biology perils they claim should be urgently –and expensively– addressed in order to avoid a “synthetic biology disaster”. Their statements on the specific difficulty of regulating, managing and monitoring synthetic organisms have been partially refuted by Tait and Castle (Nature 484, 37; 2012). In my view, assessment of the risks of synthetic organisms must always be based on the study of their harmful potential compared with that of both transgenic and naturally occurring organisms. From this perspective, synthetic organisms are indeed risky, but no more than transgenic or even wild species.

The ability of living beings, particularly –but not restricted to– microorganisms, to disrupt normal ecosystem functioning, transfer DNA to other species, increase competition for resources or disrupt crucial ecological functions has been well documented by all branches of biology for decades. Synthetic organisms, as proposed by Dana and colleagues, might well produce toxic compounds, survive for a long time in the environment and evolve to fill new ecological niches. But are these environmental risks “more dangerous” because a synthetic organism is involved? Just to use two examples cited by Dana et al., synthetic microbes are assumed more sophisticated because they can lack a particular metabolic pathway or spread an antibiotic resistance gene. But in nature, pathogenicity islands, recalcitrant compounds degradation and many other gene networks are horizontally (inter-specifically) gained and lost on a daily basis. Regarding antibiotic resistance traits, they are almost ubiquitous –unfortunately– in hospitals, where undesired artificial selection accounts for their spreading.

We should stop treating synthetic organisms as inherently “different”: they might be artificial but, as living entities, share the same evolutionary features –and threads– of both transgenic and natural organisms. The risks lie in their use, not in their nature.