What is PCR testing?
PCR is an acronym for polymerase chain reaction. PCR increases the amount of DNA available from a sample for typing and analysis. Within the DNA string, some areas are the same for all human beings (conserved, or constant). Other areas tend to vary from person to person (variable, or polymorphic). The variable regions are usually scattered among the conserved regions and are used in DNA testing profiles. Most organisms naturally copy their DNA in the same way. The PCR mimics this process, except replication takes place in a test tube. When any cell divides, enzymes called polymerases make a copy of all of the DNA in each chromosome. DNA polymerase is also used in PCR to make copies of specific target strands. DNA is made from four nucleotide bases, represented by the letters A (adenine), C (cytosine), G (guanine), and T (thymine). The A on one strand of DNA always pairs with the T on the opposite strand, and C always pairs with G. The two strands are said to be complementary to each ot
