DNA sequencing traces with noisy or weak signal
Identification of weak signal traces
- The trace peaks are misshapen and/or contain secondary peaks under the primary peak (Figure 1A).
- The sequencing peaks are very weak (under 150 units) in the raw channel before base 300 (Figure 1B).
- The total quality scores counts are generally low.
Figure 1. Example of a noisy or weak trace. (A) Processed data channel. (B) Raw channel data. Note the misshapen secondary peaks in the processed channel and the very low signal strength (~100 units) in the raw channel.
Causes of weak signal traces
- Partially failed sequencing reaction.
- Too much or too little DNA.
- Partial loss of sample during clean-up
- Any of the other causes listed on failed DNA sequencing reaction page.
Solving weak signal traces
- The solutions for solving weak signal traces are basically the same as those for solving failed reactions. For help on this problem see the solutions listed on the failed DNA sequencing reaction page.
For more information on detecting DNA sequencing trace problems please visit the QualTrace DNA sequencing analysis software page.
Return to the main DNA sequencing troubleshooting page.