To prepare us for future pandemics, researchers at the Helmholtz Institute for One Health (HIOH) not only look at the pathogens, but also at how changes in the environment and nature - including those caused by us - influence how pathogens have developed in the past. Prof. Sébastien Calvignac-Spencer heads the research group "Evolution of Pathogens" at HIOH and uses genetic changes to retrospectively analyse what could have caused this change. In the HZI podcast InFact, he explains how this allows valuable conclusions to be drawn about how today's pathogens could develop.