Figure 2

STACE experimental procedure. Template cDNA is used in two separate PCR reactions that utilize primers based on the sequence of a SAGE tag, the SL1 sequence and modified oligo d(T) primer. The PCRs produce an amplicon representative of the sequence upstream of the SAGE tag location (PCR product 1), and another that comes from the downstream sequence (PCR product 2). These products are sequenced, and mapped to the C. elegans genome. Those sequences whose alignments overlap with the SAGE tag used in primer design are considered true positive STACE results.