Methods Used to Manipulate and Analyze DNA

Forensic DNA typing was made possible not only by advances in knowledge about DNA structure and function but also by advances in the methods and techniques allowing DNA to be manipulated. Different manipulation methods apply to different DNA-typing technologies. For example, nuclear DNA was first typed using the restriction fragment length polymorphism (RFLP) technique. This procedure did not rely on the polymerase chain reaction but on restriction enzymes and Southern blots. (Southern blotting is discussed later in this chapter.) By contrast, the current typing procedure does rely on PCR but does not make use of restriction enzymes.