A question we occasionally get asked is how to prevent users from accidentally reprocessing traces if they open them in Sequence Analysis. Since PeakTrace does not change the raw data in the .ab1 file by default, it is possible to reprocess the trace files through the KB™ or the ABI Basecaller again. This will regenerate the original pre-PeakTrace trace, thus losing the PeakTrace sequence. This problem can be avoided by using the Noise Raw Data option.
The Noise Raw Data setting replaces the raw data channels with a random signal that prevents the accidental reprocessing of traces by KB or the ABI Basecaller.
Figure 1 shows an example of the normal raw data channels contained within a .ab1 trace file. Figure 2 shows the raw data of the same trace after using the Noise Raw Data setting. Attempting to re-basecall the .ab1 file using KB will result in a KB processing error, thus preventing the PeakTrace basecalls and peaks from being lost.
Figure 1. Example of raw data channels contained within a .ab1 trace file.
Figure 2. Example of the raw data channel of use of Noise Raw Data setting.
It is strongly recommended that if this setting is used that the the original .ab1 files are kept, since in the event that the KB version of the trace file is is required, there is no way to recover it once this option has been applied. This setting is off by default.