A casual term for the molecular weight (base pair) standards run in parallel with DNA samples to calibrate an electrophoretic gel. Each rung of the ladder represents a different size of polynucleotide. DNA laddering is the term applied to the pattern of DNA fragmentation seen in apoptotic cells and refers to the pattern seen on a gel. The activity of the endonuclease DNase γ (endo G) generates fragments that are multiples of the 180-bp nucleosomal unit (see DNA fragmentation factor).
Subjects: Medicine and Health.