For much of its history, the field of transcription regulation was firmly in the realm of biochemists who constructed elegant models of molecular-scale phenomena from relatively abstract data. In the late 1960s, when the idea of the central dogma was barely a decade old, and RNA polymerases had just been discovered, Oscar Miller broke from this mould by developing a technique dubbed ‘Miller spreads’. He extracted chromatin from nuclei, spread it on electron microscopy grids and directly visualized transcription using transmission electron microscopy.

His group published a series of papers with exceptional images that brought a rare visual concreteness to mechanisms of gene regulation and provided insights that were, at the time, out of the reach of biochemical methods. These images alone answered now seemingly simple questions, such as whether genes have distinct beginnings and ends, whether multiple polymerases can act on a gene simultaneously and whether transcription occurs in a single direction.