Spindle vs. Microtubule Ball (IMAGE) Northwestern University Caption A spindle (top, left) is an elaborate football-shaped structure that physically separates chromosomes during cell division, ensuring that each newly divided cell obtains the correct amount of genetic material. The blue represents the chromosomes, and two spindle components are shown in green and red; green are fibers called microtubules that attach to the chromosomes, and the red protein marks the two spindle ends. The bottom right image represents a spindle in which two proteins -- KLP-15 and KLP-16 -- were knocked out in Sadie Wignall's research, causing the spindle structure to collapse into a messy round ball. Credit Northwestern University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.