Based on pre-alignment QA/QC, we need to trim low quality bases from the 3' end of reads.
- Select the Unaligned reads data node
- Select Trim bases from the Pre-alignment tools section of the task menu (Figure)
We will configure Trim bases to remove base pairs from the 3' end of reads until it reaches a base pair call with a Phred score of equal to or greater than 20. Hover over any () to get additional information about a specific option (Figure).
- Set Trim based on to Quality score
- Set End min quality level (Phred) to 20
- Set Trim from end to 3-prime (right end)
- Leave Advanced options set to default
- Select Finish
The Trim bases task will generate a new data node, Trimmed reads. While tasks have been queued or are in progress they have a lighter color. Any output nodes that the task will generate, such as the Trimmed reads data node from the Trim bases task, are also displayed in a lighter color until the task completes (Figure).
Once a task begins running, a progress bar is displayed (Figure).
We can view the task report for Trim bases by selecting either the Trim bases task node or the Trimmed reads data node and choosing Task report from the task menu.
- Select the Trimmed reads data node
- Select Task report from the task menu
The report shows the percentage of trimmed reads and reads removed (Figure).
The results are fairly consistent across samples with ~65% of reads untrimmed, ~30% trimmed, and ~5% removed for each.
Additional Assistance
If you need additional assistance, please visit our support page to submit a help ticket or find phone numbers for regional support.
Your Rating: | Results: | 0 | rates |