Seqanswers Leaderboard Ad

Collapse

Announcement

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

  • Velvet + meta-velvet:which fastq format for paired-end infos?

    Hi,
    I've been doing some metagenomic assemblies using meta-velvet. I've been using paired-end data for mor reliable assemblies. However, when I wanted to check those assemblies (e.g. using tablet) I could not find the paired end info any-more.
    I've recently learned that fastq-formats have changed not only with respect to quality values, but also with respect to paired-end info.

    Old format:
    @HWUSI-EAS100R:6:73:941:1973#0/1
    New Format (that I am using):
    @EAS139:136:FC706VJ:2:2104:15343:197393 1:Y:18:ATCACG
    (paired-end info bold and underlined)

    So Mira for example needs the old format and will just ignore paired-end info it doesn't recognize (without warning!) if you use the new Format.

    Does anybody know which Format Velvet and Meta-Velvet use? Are my assemblies now all in reality single-read assemblies?

  • #2
    Velvet + meta-velvet:which fastq format for paired-end infos?

    I have been using velvet with the new formats of MiSeq and HiSeq PE data, and it works fine.

    By the way, in the read that you have used to illustrate the new format, the Y (1:Y:18:ATCACG) indicates a read that has not passed Illumina's QC filter step.

    Usually the sequence providers remove those reads.

    Comment


    • #3
      Velvet ignores fastq headers and replaces them with its own (fasta) headers anyway. You just have to make sure that input read pairs are either shuffled in one file, or synced if separate files are used.

      Comment


      • #4
        @mastal
        Thanks, but the example reads I've posted are not mine. they are from the wikipedia page illustrating the differences between the fastq-formats.
        @mastal+@muol:
        But then how can I check the assemblies with regard to paired-end Infomation? With Mira, for example, I know that you still get assemblies (without error-messages) if you use the wrong format. The assemblies will just in reality be based on single-read assemblies. So how can one really make sure if everything is ok, if the paired-end info is left out from the AMOS-file, the sequence-list and everything? (This just intrigues me. For some contigs i would simply like to check how well supported they are by paired reads. Also a lot of reads are not assembled or dropped from the assembly. I would like to see what has happened to their corresponding partners)
        Last edited by someperson; 07-04-2013, 08:29 AM.

        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...
          Yesterday, 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
        57 views
        0 likes
        Last Post seqadmin  
        Started by seqadmin, 04-10-2024, 10:19 PM
        0 responses
        53 views
        0 likes
        Last Post seqadmin  
        Started by seqadmin, 04-10-2024, 09:21 AM
        0 responses
        45 views
        0 likes
        Last Post seqadmin  
        Started by seqadmin, 04-04-2024, 09:00 AM
        0 responses
        55 views
        0 likes
        Last Post seqadmin  
        Working...
        X