Just as you make sure your socks are on before your shoes, cells make sure that their chromosomes are properly aligned before they divide. However, every time a cell divides, it runs the risk of generating cells with too few or too many chromosomes. These mistakes can cause Down Syndrome and play a role in the growth of cancers. In his Science Center Lecture Series presentation, professor Andrew Murray looks at a mysterious cellular process that may provide clues to understanding chromosomal abnormalities such as the higher incidence of children with Down Syndrome born to older women.