Accept no limits: biocontainment and the construction of a safer space for experimentation in xenobiology as a legacy of Asilomar

Researchers in xenobiology, a subdiscipline of synthetic biology, aim to build a ‘second nature’ with nucleic acid analogues, termed Xeno-nucleic acids (XNA). They promise biosafe technologies, based on the impossibility of transferring genetic material to other organisms and controlling the proliferation of genetically modified microorganisms. Proponents of xenobiology have employed metaphors and narratives that represent the separation of synthetic life from DNA-based, constituting a safer space for the exploration and navigation of virtual biological worlds. Based on interviews with synthetic biologists and participant observation in a synthetic biology laboratory, I argue that the reconfiguration of nature that xenobiologists seek is inspired by the vision of design and governance laid out in the 1975 Asilomar conference, so normative aims of safety are co-produced with visions of unnaturalness. I interrogate the types of limits that xenobiologists aim to cross, to propose that they conceive limits as pushing beyond what is biologically plausible, finding the challenge motivating. I show that the division between the natural and the unnatural is not clearly established as xenobiologists portray. In giving priority to safety as the determinant of the permissibility of new technologies, who gets to define nature and its limits remains restricted to scientists.