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low percent mapping

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2016-03-22
2016-03-24
  • Michele Mehaffey

    Hello,

    I'm aligning WGS data from a HiSeq and getting very low percent mapping, like 30-35% of the input reads? The bam file of the same fastq reads shows > 99% mapping. I've tried pe mapping with --best and single read mapping leaving that off and using -e 10, but it didn't change much. These are long reads, 250 bp, and I indexed the hg19 using --ws 13.

    Any suggestions?

    Thank you,

    Michele

     
  • Anonymous

    Anonymous - 2016-03-22

    HI Michele,

    Can you send the email to Can Alkan(calkan@gmail.com).

    Thanks,
    Farhad

     
  • Can Alkan

    Can Alkan - 2016-03-23

    Hi Michele

    In your previous email you seem to map to repeatmasked reference. If you are still using the masked reference, 35% mapping rate is normal. You are removing ~50% of the reference anyway.

    Can

     
  • Can Alkan

    Can Alkan - 2016-03-24

    yes, that is correct. Still, 35% mapping to repeatmasked genome is normal. The other alignment you have at 99% also includes common repeats, which, repeatmasking removes.

     

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