Mitosis. Light micrograph of onion (Allium cepa) root tip cells undergoing mitosis (nuclear division). Mitosis is the formation of two daughter nuclei from one parent nucleus. The cell at upper centre is in the early anaphase stage of mitosis. At anaphase sister chromatids, which are made of deoxyribonucleic acid (DNA, purple), are moved to separate poles by spindles (not seen). Two identical chromatids make up one chromosome, so each cell retains a copy of the parent cell's genetic information. Bottom right of the anaphase cell is a cell in telophase, the last stage of mitosis before cytokinesis (cellular division). Most of the cells are in interphase, the stage between mitotic divisions during which the cells grow and replicate their organelles and DNA. Magnification: x 525 at 10 centimetres tall.