The amplification protocol was as follows: initial denaturation at 94°C for 15 min, 40 cycles of denaturation at 94°C for 30 sec, annealing at 63°C for 90 sec, and extension at 72°C for 90 sec. The amplified PCR products were electrophoresed in 2% (w/v) agarose gels and stained with ethidium bromide.