Cells must accurately duplicate their chromosomes (genes in the cell’s nucleus) and segregate them equally to daughter cells for proper cell growth and division. Errors in segregation results in cells with abnormal numbers of chromosomes (aneuploidy), which can lead to birth defects, Down’s syndrome and cancer. Cells have developed safeguards to ensure chromosomes are accurately segregated. A region of each chromosome called the centromere is bound by kinetochore proteins which attach to spindle microtubules, tiny fibres that pull newly separated chromosomes to each side of a dividing cell. If any mistakes occur in spindle attachment, kinetochore proteins signal the spindle checkpoint machinery, which delays segregation until the defects are corrected. Using yeast as a model, Dr. Vivien Measday is studying how kinetochore proteins attach to spindle microtubles and communicate with the checkpoint machinery. The research will improve understanding of chromosome segregation and could lead to treatments for diseases caused by abnormal numbers of chromosomes.