During apoptosis, the genomic DNA is chopped into
~180 base pairs or its multiples at certain regions (internucleosomal
regions), hence appears as a ladder when
electrophoresed (Figure 6) [25]. For this reason, this
finding is a characteristic, hallmark feature of apoptosis
and is not present in necrosis. (In necrosis the cells give
a smear pattern on the gel.) As a result it is one of the
methods used to differentiate apoptosis from necrosis.
In fact, in one recent study, the agarose gel electrophoresis
along with the other methods (e.g. fluorescence microscopy
and caspase-3 activity) was successfully used to
confirm apoptosis and necrosis in one recent study [26].