The PCR amplification was carried out in a
Peltier Thermal Cycler PTC200 (Bio-Rad Laboratories,
Hercules, CA, USA). The PCR reaction mixture consisted
of 2 μL (∼15 ng) DNA, 2.5 μL of 10 × PCR
buffer, 2 μL of 25 mmol/L MgCl2, 2 μL of 2.5 mmol/L
dNTPs, 1.0U Taq DNA polymerase (SBS Genetech,
Beijing, China), and 1.0 μL (2.5 μmol/L) each of the
forward and reverse primers (Sangon, Beijing, China)
in a final volume of 25 μL. The PCR products were run
on a 1.0% agarose gel in 0.5× TBE buffer