Karyorrhexis

Karyorrhexis (from Greek κάρυον karyon, "kernel, seed or nucleus", and ῥῆξις rhexis, "bursting") is the destructive fragmentation of the nucleus of a dying cell whereby its chromatin is distributed irregularly throughout the cytoplasm. It is usually preceded by pyknosis and can occur as a result of either programmed cell death (apoptosis), senescence, or necrosis.

In apoptosis, the cleavage of DNA is done by Ca²⁺ and Mg²⁺ -dependent endonucleases.