DNA Fragmentation plays an important part in forensics, especially that of DNA profiling.
* Restriction Fragment Length Polymorphism (RFLP) is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a restriction endonuclease.  The restriction endonuclease cuts DNA at a specific sequence pattern known as a restriction endonuclease recognition site.  The presence or absence of certain recognition sites in a DNA sample generates variable lengths of DNA fragments, which are separated using gel electrophoresis. They are then hybridized with DNA probes that bind to a complementary DNA sequence in the sample.
* In polymerase chain reaction (PCR) analysis, millions of exact copies of DNA from a biological sample are made. It used to amplify a specific region of a DNA strand (the DNA target). Most PCR methods typically amplify DNA fragments of between 0.1 and 10 kilo base pairs (kb), although some techniques allow amplification of fragments up to 40 kb in size. PCR also uses heat to separate the DNA strands.
* DNA fragmented during apoptosis, of a size from 1 to 20 nucleosomes, can be selectively isolated from the cells fixed in the denaturing fixative ethanol