Briefly,PCR assays were performed in 25 l using the polymerase TaKaRa Ex Taq (TaKaRa Bio, Inc.) in a Tetrad2 thermal cycler (Bio-Rad, Hercules, CA) under the following cycling conditions: an initial denaturation step at 95°C for 5 min and 25 cycles of 1 min at 95°C,1 min at 56°C,and 1 min at 72°C.