Five-microliter PCR product (300-500 ng) was mixed with 0.5 ml Enhancer TM and 0.5 ml Surveyor TM (Transgenomic) and incubated at 428C for 20 min followed by adding 0.5 ml Stop-solution, as per manufacturer's protocol. The inactivated Surveyor TM -digested product was purified with PCR QiaQuick TM purification kit (Qiagen) and eluted in 35 ml water. In some experiments, the PCR product was mixed with an approximately equal amount of PCR product from wild-type DNA prior to forming cross-hybridized sequences, to facilitate detection of homozygous mutations.