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  • ehlin
    Member
    • Jan 2012
    • 12

    samtools psl2sam.pl usage?

    I have a .psl file generated from BLAT. I want to convert it to SAM so I can sort out relevant sequences. I tried using psl2sam.pl in SamTools but when I try to view I get:

    [samopen] no @SQ lines in the header.
    [sam_read1] missing header? Abort!

    I didn't specify any parameters when I ran psl2sam.pl, and I have no idea what any of them mean. The usage says:

    Usage: psl2sam.pl [-a 1] [-b 3] [-q 5] [-r 2] <in.psl>

    I have no idea what this means, could anyone explain? Thanks.
  • mgogol
    Senior Member
    • Mar 2008
    • 197

    #2
    Well, usually that means a sam file is missing a header... I wonder if it wants one on the psl file, that seems weird. You can generate a header with:

    samtools view -bt genome.fa.fai sample.sam
    or
    picard CreateSequenceDictionary

    Comment

    • kmcarr
      Senior Member
      • May 2008
      • 1181

      #3
      Originally posted by ehlin View Post
      I have a .psl file generated from BLAT. I want to convert it to SAM so I can sort out relevant sequences. I tried using psl2sam.pl in SamTools but when I try to view I get:

      [samopen] no @SQ lines in the header.
      [sam_read1] missing header? Abort!

      I didn't specify any parameters when I ran psl2sam.pl, and I have no idea what any of them mean. The usage says:

      Usage: psl2sam.pl [-a 1] [-b 3] [-q 5] [-r 2] <in.psl>

      I have no idea what this means, could anyone explain? Thanks.
      Could you please show exactly the command you used.

      Comment

      • freeseek
        Junior Member
        • Feb 2010
        • 8

        #4
        Command line for psl2bam conversion

        Assuming ref.fasta is the reference file used for alignment with blat and in.psl is the output of the blat alignment, these commands will generate the bam file from the blat alignments:
        Code:
        samtools faidx ref.fasta # if the reference is not already indexed
        psl2sam.pl in.psl | samtools view -bt ref.fasta.fai -o out.bam -

        Comment

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