Kary   Mullis   (Nobel  1993)  developed  the
   Polymerase  Chain Reaction (PCR) to amplify the quantity of target DNA
   in vitro.
<Li> The target DNA is denatured into single strands.
<Li> Each strand is annealed to a short, complementary primer.
<Li> DNA  polymerase  and  nucleotides  extend  the  primers, using the
single-stranded DNA as a template.

   After  one  cycle  of amplification, the amount of target DNA has been
   doubled.