In the last decade, yeast genetics has played an instrumental role in identifying conserved components of the machinery that holds sister chromatids together and promotes their separation at anaphase. However, we still lack a molecular understanding which can explain the 'all-or-nothing' nature of sister chromatid separation. A formidable challenge for the future will be to elucidate how multiple layers of control act at both the level of separase and its substrate to regulate the global cleavage of cohesin at anaphase. Such a challenge will benefit from the development of in vivo real-time, high-resolution biomarkers of separase activation and cohesin cleavage. Furthermore, a move towards specifically compromising securin's inhibitory function without affecting the protein's chaperone role is required if we are to understand the true value of other pathways controlling separase activation and cohesin cleavage.