Hi Alison,

mpileup ignores reads with the flags UNMAP,SECONDARY,QCFAIL,DUP. The
status of the mate is not checked by default.

Best wishes,
Petr

On Wed, 2015-11-18 at 10:36 +0000, Wright, Alison wrote:
> I wish to call SNPs using SAMtools mpileup function.
> 
> I first map my Illumina paired end reads to the reference using Bowtie
> and then I have custom scripts that filter out non-uniquely mapping
> reads. To do this I rely on the absence of XS to indicate a uniquely
> mapped read. 
> 
>  
> 
> However, this creates a potential problem as the SAM flags are often
> no longer meaningful. 
> 
> Eg. Originally I have two reads that are paired and both map 
> 
> Forward read flag 83 
> 
> Reverse read flag 163
> 
> If Forward read is not uniquely mapping then I remove this from the
> sam file, leaving Reverse read intact. The flag of Reverse read is not
> changed and therefore now falsely indicates it has a mapped pair. This
> isn’t a problem if my downstream programs do not use the flag.
> 
>  
> 
> Therefore, I wanted to check, does the mpileup function read/use the
> flags in the sam file?
> 
>  
> 
> If so, is there another way to only use uniquely mapping reads to call
> SNPs.
> 
>  
> 
> Thanks very much
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Samtools-help mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/samtools-help




-- 
 The Wellcome Trust Sanger Institute is operated by Genome Research 
 Limited, a charity registered in England with number 1021457 and a 
 company registered in England with number 2742969, whose registered 
 office is 215 Euston Road, London, NW1 2BE. 

------------------------------------------------------------------------------
_______________________________________________
Samtools-help mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/samtools-help

Reply via email to