Seqanswers Leaderboard Ad

Collapse

Announcement

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

  • Quality Score Format

    Is there any difference in the quality score format of a sample (FASTQ) file generated by HiSeq 2000 and that by Genome Analyzer II ?


    Thank you,
    Vedbar

  • #2
    There are no differences between machines, but there are between software versions. The recently released CASAVA 1.8 outputs FASTQ files with Q-scores using Phred+33 encoding as opposed to the Phred+64 used in previous versions.

    Comment


    • #3
      Thank you for your answer.

      Comment


      • #4
        Hi kmcarr,

        I know that CASAVA v1.8 is reported to produce Phred+33 Q-scores, but I just checked the export files from our last run and observed quality values up to 'i' (which would be 72!). I'll contact Illumina tech support later today and get the scoop.

        Harold

        Comment


        • #5
          Follow-up:

          The bam files contain Phred+33 Q-scores, while the export files contain Phred+64.

          Aaaarrgghh!

          Comment


          • #6
            Originally posted by HESmith View Post
            Follow-up:

            The bam files contain Phred+33 Q-scores, while the export files contain Phred+64.

            Aaaarrgghh!
            See new post on the earlier thread, http://seqanswers.com/forums/showpos...9&postcount=64

            It sounds like they've fixed their FASTQ (good), but not the in house "export" format (confusing!)

            SAM/BAM have always explicitly required PHRED scores + 33 for the ASCI encoding (like Sanger FASTQ).

            Probably best to continue this here: http://seqanswers.com/forums/showthread.php?t=8895
            Last edited by maubp; 07-19-2011, 03:46 AM. Reason: typo

            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, 04-11-2024, 12:08 PM
            0 responses
            59 views
            0 likes
            Last Post seqadmin  
            Started by seqadmin, 04-10-2024, 10:19 PM
            0 responses
            57 views
            0 likes
            Last Post seqadmin  
            Started by seqadmin, 04-10-2024, 09:21 AM
            0 responses
            52 views
            0 likes
            Last Post seqadmin  
            Started by seqadmin, 04-04-2024, 09:00 AM
            0 responses
            56 views
            0 likes
            Last Post seqadmin  
            Working...
            X