Question: Get bowtie2 to ignore isoform variants from Trinity assembly?
gravatar for CephBirk
6 days ago by
Woods Hole, MA, USA
CephBirk0 wrote:

So I've run bowtie2 against my Trinity assembly and get a high proportion of paired end reads that align concordantly at more than one place. I am suspicious that they're aligning to multiple isoform variants all from the same "gene" group.

Fortunately, I've got a Trinity assembly that also includes a gene_trans_map that identifies which isoforms belong with which "gene" grouping.

How can I get bowtie2 to ignore isoform variants with a given "gene" group (defined by gene_trans_map) when it calculates the percent of reads that concordantly align exactly once or more than one time? I haven't been able to find anything like this in the help page but I would suspect this may be a common thing people want to do... I would prefer not to have to use the -a parameter given how much this slows things down.

rna-seq • 73 views
ADD COMMENTlink modified 5 days ago by h.mon26k • written 6 days ago by CephBirk0
gravatar for h.mon
5 days ago by
h.mon26k wrote:

Try collapsing the trascriptome assembly into supertranscripts, this should alleviate the multi-mapping problem. See the Trinity documention on SuperTranscripts.

ADD COMMENTlink written 5 days ago by h.mon26k

Thanks! This is just what I was looking for and does shift about 20% of my reads from the "aligned concordantly >1 times" category to the "exactly one time" category.

ADD REPLYlink written 5 days ago by CephBirk0
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