Transgenes and Transgressions: Scientific dissent as heterogeous practice

and consequences of scientific controversy, no coherent theory of scientific dissent has emerged. This article proposes the elements of such a framework, based on understanding scientific dissent as a set of heterogeneous practices. I use the controversy over the presence of transgenic DNA in Mexican maize in the early 2000s to point to a processual model of scientific dissent. 'Contrarian science ' includes knowledge claims that challenge the dominant scientific trajectory, but need not necessarily lead to dissent. 'Impedance ' represents efforts to undermine the credibility of contrarian science (or contrarian scientists) and may originate within or outside of the scientific community. In the face of impedance, contrarian scientists may become dissenters. The actions of the scientist at the center of the case study, Professor Ignacio Chapela of the University of California, Berkeley, demonstrate particular practices of scientific dissent, ranging from 'agonistic engagement ' to 'dissident science'. These practices speak not only to functional strategies of winning scientific debate, but also to attempts to reconfigure relations among scientists, publics, institutions, and politics that order knowledge production