Biology’s Dark Matter: From Galaxies to Microbes

Emergent research in metagenomics has unveiled large quantities of previously unknown and unclassified prokaryotic DNA. As these prokaryotes constitute the vast majority of microbial life in environmental samples, some microbiologists and commentators in scientific media have referred to this expansive unknown as ‘biological dark matter’, translating the rhetorical power of dark matter from the physical to the life sciences. Engaging literatues and approaches from across the philosophy, history, and social studies of science, we explore the cultural significance of the dark matter theory in the physical sciences and examine the implications of its conceptual reworking in biology, through critically engaging the political narratives folded within dark matter’s genealogies. ‘Dark matter’ designates both zones of importance and zones of turbulence, simultaneously emphasizing microbiologists’ creativity whilst constructing new ways of relating to microbiota. Such a situation, we propose, also invites theoretical analysis as it calls for a conceptual reconsideration of the gene and its fundamental role within the life sciences.