Fluorescent light micrograph of a cell in anaphase of mitosis (nuclear division). Mitosis is the formation of two daughter nuclei from one parent nucleus. Fluorescent markers have been used to highlight alpha tubulin (green), a component of microtubules, and DNA (deoxyribonucleic acid, pink). During anaphase the sister chromatids of each chromosome are pulled to opposite poles by the mitotic spindle, the main component of which are microtubules. Two identical chromatids make up one chromosome, so each cell retains a copy of the parent cell's genetic information.