Seqanswers Leaderboard Ad

Collapse

Announcement

Collapse
No announcement yet.
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • BWA errors after quality trimming

    After I use the "-q 20" option in bwa aln I start getting errors down the road eg when i run ValidateSamFile in picard I get lots of "Mate negative strand flag does not match read negative strand flag of mate" and then "Sequence and quality are inconsistent" errors as well. I have run all the same commands without the -q option without these problems. I am very new to all this and not sure where I'm going wrong!

  • #2
    A little late, but I am also running -q option and curious if you identified the problem.

    Comment


    • #3
      No I ended up just running it without trimming as I decided it wasn't really necessary

      Comment


      • #4
        This is a bug in BWA. If you use -q it puts the trimmed nucleotide read in the output SAM file but the quality sequence is not trimmed at all and thus there is a difference in the length of the read and the length of the quality string. Either use some third party tool like trimgalore to trim your fastq reads before aligning and don't use BWA -q option at all OR use some script that takes SAM file and trims off the base quality string accordingly.

        PS:This post may help- http://www.biostars.org/post/show/13...or-space-data/

        Comment

        Latest Articles

        Collapse

        • seqadmin
          Essential Discoveries and Tools in Epitranscriptomics
          by seqadmin




          The field of epigenetics has traditionally concentrated more on DNA and how changes like methylation and phosphorylation of histones impact gene expression and regulation. However, our increased understanding of RNA modifications and their importance in cellular processes has led to a rise in epitranscriptomics research. “Epitranscriptomics brings together the concepts of epigenetics and gene expression,” explained Adrien Leger, PhD, Principal Research Scientist...
          04-22-2024, 07:01 AM
        • seqadmin
          Current Approaches to Protein Sequencing
          by seqadmin


          Proteins are often described as the workhorses of the cell, and identifying their sequences is key to understanding their role in biological processes and disease. Currently, the most common technique used to determine protein sequences is mass spectrometry. While still a valuable tool, mass spectrometry faces several limitations and requires a highly experienced scientist familiar with the equipment to operate it. Additionally, other proteomic methods, like affinity assays, are constrained...
          04-04-2024, 04:25 PM

        ad_right_rmr

        Collapse

        News

        Collapse

        Topics Statistics Last Post
        Started by seqadmin, Today, 08:47 AM
        0 responses
        12 views
        0 likes
        Last Post seqadmin  
        Started by seqadmin, 04-11-2024, 12:08 PM
        0 responses
        60 views
        0 likes
        Last Post seqadmin  
        Started by seqadmin, 04-10-2024, 10:19 PM
        0 responses
        59 views
        0 likes
        Last Post seqadmin  
        Started by seqadmin, 04-10-2024, 09:21 AM
        0 responses
        54 views
        0 likes
        Last Post seqadmin  
        Working...
        X