Abstract The ‘new genetics’ (or genomics) has penetrated overwhelmingly into a broad range of domains in the contemporary world, spawning a technocultural revolution in relation to genes that has transformed technologies, institutions, practices and ideologies. The ‘new genetics’ has not only reshaped the biological, cultural and social loci in the immediate surroundings of individuals, but also reconfigures wide-ranging macro-social, historical and political relations. In this article we approach the technocultural revolution surrounding the ‘new genetics’ by means of a case study on the overlapping of race, genomics, identities and politics in Brazil. We analyze how the ‘new genetics’ extends far beyond the biological dimension to become an arena for dispute in which historical, social and political elements are present. Specifically, we will analyze the debate over the results of a survey that aimed to shed light on the ‘genetic origins of Brazilians’ based on the sequencing of parts of mitochondrial DNA and the Y chromosome. By focusing on how this survey was received, we will explore some of the new, intense and abundant forms of relations between ‘nature/genetics’ and ‘culture/society’, in which DNA appears as an outstanding player in the dispute between modalities for interpreting and transforming social and political realities.