What tasks need to be done today, and which is the most urgent? People have to constantly set priorities in their daily life. Bacteria are no different: They too must prioritize when combating viruses with CRISPR. However, it was unclear how this prioritization takes place. Scientists from the Helmholtz Institute for RNA-based Infection Research (HIRI) in Würzburg, a joint venture of the Helmholtz Centre for Infection Research (HZI) in Braunschweig and the Julius Maximilian University (JMU) Würzburg, in cooperation with researchers from the universities of Würzburg, Freiburg and Leipzig, have now described an underlying mechanism for the first time. Their study was published in the journal Nature Microbiology.