I am using miRDeep2 to analyze small RNA-Seq data.
When running mapper.pl, two log files were produced in the system: bowtie.log and mapper.log.
Before executing the bowtie function to map reads to genome index, mapper.pl has done (1) parsing fastq to fasta format (2) discarding sequences with non-canonical letters (3) discarding short reads (4) collapsing reads.
The bowtie.log looks like below:
# reads processed: 138945
# reads with at least one reported alignment: 74938 (53.93%)
# reads that failed to align: 50691 (36.48%)
# reads with alignments suppressed due to -m: 13316 (9.58%)
Reported 122526 alignments to 1 output stream(s)
However, the Mapping statistics of mapper.log shows:
parsing fastq to fasta format
discarding sequences with non-canonical letters
discarding short reads
collapsing reads
mapping reads to genome index
trimming unmapped nts in the 3' ends
Log file for this run is in mapper_logs and called mapper.log_33416
Mapping statistics
#desc total mapped unmapped %mapped %unmapped
total: 11965391 11469171 496220 0.959 0.041
seq: 11965391 11469171 496220 0.959 0.041
In the Mapping statistics, the total column equals to the number of fastq reads in the original fastq file.
I was wondering which mapping statistics should I trust and what's the difference between these two?
1 answer
Hi, an answer to this question was provided by Devon Ryan in this post: Understanding miRdeep2 mapper output. In case you did not come across this yet. Best of luck!
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Hi, Im having the same dilema, did you came to a conclution that you can share? or maybe another tool you recomend for aligning miRNAseq reads
best regards.