Question: Why gene counts from RNA STAR don't match total uniquely mapped counts
1
gravatar for daniel.kim
6 months ago by
daniel.kim • 30
Qiagen Sciences - Frederick Maryland
daniel.kim • 30 wrote:

Hi,

I used RNA STAR to map my reads for a stranded-RNAseq library. Within RNA STAR, i turned on the option to include gene counts and so I included an hg38 GTF file from UCSC table browser. RNA STAR said that of my 20 million total reads, 86% uniquely map (so 17 million reads uniquely mapping), however, when I take the sum of all the gene counts that RNA STAR outputs, it only adds up to 5 million reads. My question is how come the total sum of all the gene counts doesn't add up to 17 million reads and why is it only 5 million? Considering that I'm using RNA STAR to do both the alignment and gene counting I thought they should be concordant.

Thanks!

rna-seq alignment galaxy • 372 views
ADD COMMENT • link • modified 6 months ago by Devon Ryan • 1.9k • written 6 months ago by daniel.kim • 30
0
gravatar for Devon Ryan
6 months ago by
Devon Ryan • 1.9k
Germany
Devon Ryan • 1.9k wrote:

Many alignments in your dataset aren't to genes, but rather intronic or intergenic regions. Those can't be in the counts but can still align uniquely.

ADD COMMENT • link written 6 months ago by Devon Ryan • 1.9k

Hi Devon,

This is RNAseq data not DNAseq. Using Agilent Universal Human Reference RNA that has undergone additional DNAse treatment so it can't be from DNA.

ADD REPLY • link written 6 months ago by daniel.kim • 30

Some RNA-seq reads will map to non-transcript/gene defined regions on the genome.

ADD REPLY • link modified 6 months ago • written 6 months ago by Jennifer Hillman Jackson ♦ 25k
Please log in to add an answer.

Help
Access

Use of this site constitutes acceptance of our User Agreement and Privacy Policy.
Powered by Biostar version 16.09
Traffic: 173 users visited in the last hour