During cell division, chromosomes are duplicated and separated so that one copy of each chromosome is inherited by each of the two emerging daughter cells. Correct distribution of chromosomes requires high accuracy and defects in this process can cause aberrant distribution of chromosomes and facilitate cancer development. By analyzing the structure of the protein responsible for chromosome separation, an international team, led by scientists from the University of Geneva (UNIGE), has shed light on the mechanisms controlling this essential player in cell division. This work is published in the journal Nature.