The condition of PCR reaction was as follows: 94°C for 3 min, 25 cycles of 94°C for 1 min, 58°C for 1 min and 72°C for 2 min, and extension at 72°C for 10 min. Aliquots of the PCR products (5 μL) were fractionated by electrophoresis on 1.5% agarose gel containing ethidium bromide, and captured as digital images under UV.