Section II: Troubleshooting a CEQ System Problem
22
CEQ™ 8000 Series Genetic Analysis System
Insertions Caused by n-1 primers
The presence of a significant percentage of n-1 primer in a primer preparation can lead
to small peaks preceding the true sequence peaks. In certain cases these small peaks
will be called as bases in the sequence. This will most often occur in a sequence that
has a “G” followed by an “A”. However multiplets (i.e. TT or CC) may also yield
insertions. In Figure 16, the presence of a large amount of n-1 primer (~20%) in the
sequencing primer causes each true sequencing peak to be preceded by a smaller
prepeak. As can be seen in Figure 16, in many cases, these prepeaks are called as
bases.
Figure 16: High amount of n-1 primer
Inserted bases caused by n-1
primers
Pre-peaks caused by n-1
primers
