Each amplification was performed in a 25mL reaction volume containing 20 mM Tris–HCl (pH 8.4), 50 mM KCl, 2 mM MgCl2,800mM dNTP (dATP:dTTP:dCTP:dGTP in a 1:1:1:1 ratio), 0.25mM of primers, 1 U of PlatinumTaq polymerase (Invitrogen, Life Technologies)