A 0.7-ll aliquot of each amplicon was mixed with 7 ll ofloading dye (98% formamide, 10 m M EDTA, 0.025%bromophenol blue, 0.025% xylene–cyanol). After dena-turation at 95°C for 5 min, samples were rapidly cooled onwet ice and then loaded on 16 9 18 cm, 7% acrylam-ide:bisacrylamide (37.5:1) (Bio-Rad) gels. Electrophoresiswas performed using Protean II xi cells (Bio-Rad), at 220 V for 18 h at 25°C in 0.59 TBE buffer. Gels weresilver-stained according to the method of Byun et al. [9].