Fluorescent light micrograph of cells during mitosis (nuclear division). Mitosis is the formation of two daughter nuclei from one parent nucleus. Fluorescent markers have been used to highlight DNA (deoxyribonucleic acid, blue), alpha tubulin (red), a component of microtubules, and condensin (green). Condensin plays a role in the condensing of chromosomes during prophase and prometaphase (left). The cell that is second from left is in metaphase, with the chromosomes aligned along the centre of the cell. The sister chromatids of each chromosome are pulled to opposite poles during anaphase (second from right). The chromatids are pulled apart by the mitotic spindle, the main component of which are microtubules. At right, the cell is in telophase. The separated chromosomes have moved to opposite ends of the cell and two new nuclei form around them.