Quality trimming and removing adaptors
I will add a few words on the Illumina quality scores and trimming of sequencing adapters here.
Trimming
NB! Remember to start this job with the bash
command and not sbatch
as usually for job scripts on Abel.
#!/bin/bash
array=("7_1_GAGTGG_L006_R1_001.fastq.gz" "6_2_CGTACG_L006_R1_001.fastq.gz" "6_1_GTTTCG_L006_R1_001.fastq.gz" "5_1_GTGGCC_L006_R1_001.fastq.gz" "4_2_GGCTAC_L006_R1_001.fastq.gz" "4_1_TAGCTT_L006_R1_001.fastq.gz" "3_1_GATCAG_L006_R1_001.fastq.gz" "2_2_ACTTGA_L006_R1_001.fastq.gz" "2_1_TTAGGC_L006_R1_001.fastq.gz" "1_2_ATCACG_L006_R1_001.fastq.gz")
for SAMPLE_ID_R1 in "${array[@]}"
do
SAMPLE_ID_R2=${SAMPLE_ID_R1%%R1_001.fastq.gz}"R2_001.fastq.gz"
#set a prefix to make understanding what has been done to the file easier
PREFIX=trimmed_
PREFIX_SE=SE_
#create the new file name (e.g. trimmedgly7a.fq.gz)
NEWTRIMFILE_R1=${PREFIX}$SAMPLE_ID_R1
NEWTRIMFILE_R2=${PREFIX}$SAMPLE_ID_R2
SE_TRIMFILE_R1=${PREFIX_SE}$SAMPLE_ID_R1
SE_TRIMFILE_R2=${PREFIX_SE}$SAMPLE_ID_R2
cat > yourpathtoScriptsDirectory/trimmomatic_${SAMPLE_ID_R1}.slurm <<EOF
#!/bin/sh
#SBATCH --job-name=trim
#SBATCH --account=uio
#SBATCH --time=100:00:00
#SBATCH --mem-per-cpu=8G
#SBATCH --output=slurm-%j.base
## Set up job environment:
source /cluster/bin/jobsetup
module purge # clear any inherited modules
set -o errexit
#do the trimming
java -jar ~/Trimmomatic-0.35/trimmomatic-0.35.jar PE -phred33 -threads 8 ../SequenceData/RawSeqs/$SAMPLE_ID_R1 ../SequenceData/RawSeqs/$SAMPLE_ID_R2 ../SequenceData/TrimmedSeqs/$NEWTRIMFILE_R1 ../SequenceData/TrimmedSeqs/$SE_TRIMFILE_R1 ../SequenceData/TrimmedSeqs/$NEWTRIMFILE_R2 ../SequenceData/TrimmedSeqs/$SE_TRIMFILE_R2 ILLUMINACLIP:/fullpathtotrimmomaticinstallation/Trimmomatic-0.35/adapters/TruSeq3-SE.fa:2:28:10 LEADING:28 TRAILING:28 SLIDINGWINDOW:4:28 MINLEN:36
EOF
sbatch yourpathtoScriptsDirectory/trimmomatic_${SAMPLE_ID_R1}.slurm
done
A few words about this script:
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