Extension reactions were performed by bringing the 8-L PCR reactions to 10 L with addition of 2.0 L of EraGen MC TSE solution 35 (prod. no. PN1236; EraGen Biosciences) including primers for the 579T system (prod. no. PN1310), and 0.4 L of 20ϫ EraGen CFTR TSE primer mixture; final concentrations of TSEs were 25-100 nmol/L (see Table 3 in the online Data Supplement). Reactions were cycled according to the following profile: 1 cycle of 30 s at 95°C; 5 cycles of 1 s at 95°C and 2 min at 65°C.