Fig. 1.

Evaluation of the subtraction efficiency by amplifying the cDNA of GAPDH in both the subtracted and nonsubtracted cDNA pools by PCR. (a). The products amplified for different cycles were electrophoresized on the 1·5% agarose gel. The numerical number indicated the number of PCR cycles. Lane M: 100 bp molecular mass markers. Note that the GAPDH band appeared at the 13rd cycle in the nonsubtracted pool, while it appeared at the 18th cycle in the subtracted pool. (b). The cDNA of GAPDH in both the subtracted and nonsubtracted cDNA pools were amplified for 18–24 cycles by PCR. The numerical number indicated the number of PCR cycles. Lane M1: 100 bp molecular markers, lane M2: 1kb molecular markers. The difference in GAPDH band density between the subtracted and nonsubtracted pool was detected in the PCR less than 20 cycles.