Filters reads based the number or percentage of unassigned nucleotides (Ns).
This tool utilizes the PRINSEQ package.
The filtering is calculated with PRINSEQ options -ns_max_n and -ns_max_p.
The reads that pass the filtering condition are saved to file called accepted.fastq or accepted.fasta. You can also choose to store the reads that are filtered out to a separate file (rejected.fastq or rejected.fasta). You can also print out a log file that contains information about the filtering task and statistics about how many reads were accepted and rejected.