PCR reaction mixtures contained: ddH◦O (18.25 L); 2.5 L 10 × buffer solution;2.0 L dNTP (each 2.5 mmol L2−1◦); primer, 1 L (10 mol L);0.25L Taq DNA polymerase (5 U L−1), 1 L DNA template. Amplification conditions were: 94◦C for 5 mins; 35 cycles of 94C for30 s, 51-53◦C (see Table 1) for 30 s and 72C for 1 min; followed by a final extension at 72◦C for 10 min. PCR products were separated by electrophoresis on 1.5% sepharose.