Question: Indel detectors for Ion Torrent data
0
gravatar for yelekley7
4 weeks ago by
yelekley70
yelekley70 wrote:

Hello,

Could someone please suggest a good indel detector to use on IonTorrent BWA-Mem aligned bam files. I've tried Pindel and achieved good results, however, some indels are still missed.

Thanks

indel • 170 views
ADD COMMENTlink modified 4 weeks ago by Kevin Blighe6.7k • written 4 weeks ago by yelekley70
  1. Was there a recalibration step with known indels post alignment?
  2. You can also try PINDEL derivatives like DINDEL, GINDEL etc. DINDEL takes output from PINDEL.
ADD REPLYlink written 4 weeks ago by cpad01123.0k
1
gravatar for Kevin Blighe
4 weeks ago by
Kevin Blighe6.7k
Republic of Ireland (Éire)
Kevin Blighe6.7k wrote:

I think that pindel is fine. The issue may relate to the general issues of calling indels from NGS data.

Some things to consider:

  • Have you visually look at how the reads have aligned over the regions in which indels were not called? They may be problematic regions, like for example homopolymeric regions. I would load your aligned BAMs into IGV
  • Check your mapping quality (MAPQ) filter thresholds (reads with indels will automatically receive lo MAPQ unless we specifically treat them differently
  • Consider your indel length in relation to your read length. As you're using Ion Torrent, I guess that your reads are ~75bp? If you are trying to detect indels from reads of this size, it will always be difficult.
  • Consider downloading your BAMs from the Torrent Server and then using something like GATK IndelRealigner followed by HaplotypeCaller in order to attempt to identify the indels.
ADD COMMENTlink written 4 weeks ago by Kevin Blighe6.7k
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