How to perform AddorReplaceReadGroups

I have inherited whole exome sequencing data for paired normal and tumor samples with the aim of identifying somatic variants. I have already performed the alignment to hg38, converted sam files to bam files and now would like to AddorReplaceReadGroups. I do not have the information on how many libraries were prepared. Samples were multiplexed i.e. groups of 3 - 10 samples were run per lane of the flow cell. Would it be appropriate to assume that one library was prepared per sample?


  • shleeshlee CambridgeMember, Broadie ✭✭✭✭✭

    Hi @EleniStylianou,

    I think you'll find Article#6472 helpful. In particular, I had updated this article with the section titled Deriving ID and PU fields from read names. It shows how to breakdown Illumina sequencer read names for information on read groups.

  • Thank you for your answer but I am unclear how MarkDuplicates looks for duplicate reads. If I tell the algorithm that there is one library per sample per lane instead of one library for multiple samples in multiple lanes and this is actually wrong does this create a problem?
    Thank you

  • shleeshlee CambridgeMember, Broadie ✭✭✭✭✭

    @EleniStylianou, you'll find details on MarkDuplicates in Article#6747. The article states:

    Appropriately assigned Read Group (RG) information. Read Group library (RGLB) information is factored for molecular duplicate detection. Optical duplicates are limited to those from the same RGID.

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