High Quality Content by WIKIPEDIA articles! Apoptotic DNA fragmentation is a key feature of apoptosis, a type of programmed cell death. Apoptosis is characterized by the activation of endogenous endonucleases with subsequent cleavage of chromatin DNA into internucleosomal fragments of roughly 180 base pairs (bp) and multiples thereof (360, 540 etc.). This effect can be used to detect apoptosis, for example via the DNA laddering assay, the TUNEL assay, or the Nicoletti assay.