PCR EXPLAINED IN EASY TERMS

PCR is an abbreviation for "polymerase chain reaction."   (POLL'-IM-ER-ACE).  This term applies to a wide variety of different DNA tests that differ in reliability and effectiveness.   Reliabilities of each kind of PCR test need independent verification.  PCR itself doesn't accomplish DNA typing, it only increases the amount of DNA available for typing. 

PCR uses constant regions of DNA sequence to prime the copying of variable regions of DNA sequence.

 

PCR typically uses two short pieces of known DNA called primers (small arrows below).  These serve as starting points for the copying of a region of DNA.

 

Many forensic laboratories use commercial supplied DNA testing kits that contain key components for certain PCR-based tests.  PM plus DQA1TM, Profiler PlusTM and CofilerTM and IdentifilerTM are all test kits commercially supplied by PE Applied Biosystems.  PowerPlexTM is another test kit with variations supplied by Promega.  PowerPlex kits have published primers, an advantage if the precise DNA targeted is to be recorded for posterity or studied for research.  As of 2005, Profiler PlusTM and CofilerTM and PowerPlexTM are probably the most commonly used test kits in US forensic laboratories.