Random hexamer PCR was carried out in a 25-mL mixture containing 4 mL of cDNA or DNA, 10 mM Tris-HCl (pH 8.4), 50 mM KCl, 2.5 mM MgCl 2 , 100 mM dNTPs, 1 U Taq DNA Polymerase (Promega, M1661) and 100 ng of random hexamer primers containing a linker (5'-GCCGGAGCTCTGCAGAA-TTCNNNNNN-3'). After denaturing at 95uC for 5 minutes, targets were amplified by 45 cycles of 95uC for 30 seconds, 40uC for 30 seconds, 50uC for 30 seconds, and 72uC for 90 seconds. The amplified products were detected by agarose gel electrophoresis. Pure water was used as a negative control.