Differential interference contrast (DIC) light micrograph of a cell undergoing mitosis (nuclear division) where the chromosomes, which are composed of DNA (deoxyribonucleic acid, dark purple), have been segregated in three, rather than two. This is known as tripolar segregation. Mitosis is the formation of two daughter nuclei from one parent nucleus. Missegregation of the chromosomes results in cells without the full complement of DNA, which makes them unviable. Some micronuclei (small purple dots) are also seen. Giemsa stain.