Page Comparison

Aims

...

Prior running the nf-core/sarek pipeline

...

Running a test to verify the execution of the pipeline

...

Running the sarek variant calling pipeline with a HapMap trio data

...

with real data, we will first run a test with sample data to make sure the pipeline runs properly.

Before we start using the HPC, let’s start an interactive session:

qsub -I -S /bin/bash -l walltime=10:00:00 -l select=1:ncpus=1:mem=4gb

You should be in your home directory, if unsure you can run the following command:

cd ~

List the existing files and folders:

ls -l

Let’s create a folder for the workshop

mkdir -p $HOME/workshop/sarek

Get a copy of the scripts to be used in this module

Use the terminal to log into the HPC and Now let’s create a /RNAseq/ folder to run the nf-core/rnaseq pipeline. For example‘scripts’ folder and copy all scripts that we will using in the session:

mkdir -p $HOME/workshop/sarek/scripts
cp /work/training/sarek/scripts/* $HOME/workshop/sarek/scripts/
ls -l $HOME/workshop/sarek/scripts/

• Line 1: The -p indicates create 'parental directories as required. Thus the line 1 command creates both /workshop/ and the subfolder /workshop/sarek/scripts/

• Line 2: Copies all files from /work/datasets/workshop/scripts/ as noted by an asterisk to the newly created folder $HOME/workshop/scripts/

Copy public data to your $HOME

mkdir -p $HOME/workshop/sarek/data/WES/trio
mkdir -p $HOME/workshop/sarek/data/WES/liver
cp /work/training/sarek/data/WES/trio/* $HOME/workshop/sarek/data/WES/trio
cp /work/training/sarek/data/WES/liver/* $HOME/workshop/sarek/data/WES/liver 

• Lines 1 -2: Command creates the folders to copy data

• Line 3: Copies all files from /work/datasets/workshop/sarek/data/WES/trio folder as noted by an asterisk to newly created $HOME/workshop/sarek/data/WES/trio folder.

• Line 4: Copies all files from /work/datasets/workshop/sarek/data/WES/liver folder as noted by an asterisk to newly created $HOME/workshop/sarek/data/WES/liver folder.

• sarek/scripts/

Create folders for running the nf-core/sarek pipeline

Let’s create an “RNAseq” folder to run the nf-core/rnaseq pipeline and move into it. For example:

mkdir -p $HOME/workshop/sarek
mkdir $HOME/workshop/sarek/run1_test
mkdir $HOME/workshop/sarek/run2_trio
mkdir $HOME/workshop/sarek/run3_liver
cd $HOME/workshop/sarek

• Lines 1-43: create sub-folders for each exercise

• Line 54: change the directory to the folder “run1_test”Line 6: print the current working directory

Exercise 1: Running a test with nf-core sample data

First, let’s assess the execution of the nf-core/rnaseq pipeline by running a test using sample data.

Copy the launch_nf-core_RNAseqsarek_test.pbs to the working directory

...

cat launch_nf-core_sarek_test.pbs

• nextflow command: nextflow run

• pipeline name: nf-core/sarek

• pipeline version: -r 3.3.2

• container type and sample data: -profile test,singularity

• output directory: --outdir results

Submitting the job

Submit the test job to the HPC cluster as follows:

...

results/
├── csv
│   ├── markduplicates.csv
│   ├── markduplicates_no_table.csv
│   ├── recalibrated.csv
│   └── variantcalled.csv
├── multiqc
│   ├── multiqc_data
│   ├── multiqc_plots
│   └── multiqc_report.html
├── pipeline_info
│   ├── execution_report_2024-05-08_15-28-38.html
│   ├── execution_timeline_2024-05-08_15-28-38.html
│   ├── execution_trace_2024-05-08_15-28-38.txt
│   ├── params_2024-05-08_15-41-30.json
│   ├── pipeline_dag_2024-05-08_15-28-38.html
│   └── software_versions.yml
├── preprocessing
│   ├── markduplicates
│   ├── recalibrated
│   └── recal_table
├── reports
│   ├── bcftools
│   ├── fastqc
│   ├── markduplicates
│   ├── mosdepth
│   ├── samtools
│   └── vcftools
├── tabix
│   ├── genome.bed.gz
│   └── genome.bed.gz.tbi
└── variant_calling
    └── strelka

...

The pipeline requires preparing at least 2 files:

...

patient,sample,lane,fastq_1,fastq_2
ID1,S1,L002,/full/path/to/ID1_S1_L002_R1_001.fastq.gz,/full/path/to/ID1_S1_L002_R2_001.fastq.gz

• PBS Pro script (launch_nf-core_sarek_trio.pbs) with instructions to run the pipeline

Create the metadata file (samplesheet.csv):

Change to the data folder directory:

cd $HOME/workshop/sarek/data/trio
pwd

Copy the python script “create_samplesheet_nf-core_sarek.py" to the working folder

cp /work/training/sarek/scripts/create_samplesheet_nf-core_sarek.py $HOME/workshop/sarek/data/trio

• Note: you could replace ‘$HOME/workshop/sarek/data’ with “.” A dot indicates ‘current directory’ and will copy the file to the directory where you are currently located

Check help option on how to run the script:

python create_samplesheet_nf-core_sarek.py --help

python create_samplesheet_nf-core_sarek.py -h

Let’s generate the metadata file by running the following command:

python create_samplesheet_nf-core_sarek.py --dir $HOME/workshop/sarek/data/trio \
  --read1_extension R1.fastq.gz \
  --read2_extension R2.fastq.gz \
  --out samplesheet.csv

Check the newly created samplesheet.csv file:

ls -l
cat samplesheet.cvs

Copy the PBS Pro script for running the nf-core/sarek pipeline (launch_nf-core_sarek_trio.pbs)

Copy and paste the code below to the terminal:

cp $HOME/workshop/sarek/data/WES/trio/samplesheet.csv $HOME/workshop/sarek/runs/run2_sarek_trio
cp $HOME/workshop/sarek/scripts/launch_nf-core_sarek_trio.pbs $HOME/workshop/sarek/runs/run2_trio
cd $HOME/workshop/sarek/runs/run2_trio

• Line 1: Copy the samplesheet.csv file generated above to the working directory

• Line 2: copy the launch_nf-core_sarek_trio.pbs submission script to the working directory

• Line 3: move to the working directory

View the content of the launch_nf-core_RNAseq_QC.pbs script:

cat launch_nf-core_RNAseq_QC.pbs

#!/bin/bash -l

#PBS -N nfsarek_run2_trio

#PBS -l walltime=48:00:00

#PBS -l select=1:ncpus=1:mem=5gb

cd $PBS_O_WORKDIR

NXF_OPTS='-Xms1g -Xmx4g'

module load java

#specify the nextflow version to use to run the workflow

export NXF_VER=23.10.1

#run the sarek pipeline

nextflow run nf-core/sarek \

        -r 3.3.2 \

        -profile singularity \

        --genome GATK.GRCh38 \

        --input samplesheet.csv \

        --wes \

        --outdir ./results \

        --step mapping \

        --tools haplotypecaller,snpeff,vep \

        --snpeff_cache /work/training/sarek/NXF_SINGULARITY_CACHEDIR/snpeff_cache \

        --vep_cache /work/training/sarek/NXF_SINGULARITY_CACHEDIR/vep_cache \

        -resume

• The above script will screen for germline (inherited) mutations using GATK’s haplotypecaller and then annotate the identified variants using snpeff and VEP.

• Version 3.3.2 allows running the pipeline to do quality assessment only, without any alignment, read counting, or trimming.

• The pipeline enables use to start at distinct stages, we are commencing from the start “--step mapping”

Submitting the job

Once you have created the folder for the run, the samplesheet.csv file, and launch.pbs, you are ready to submit the job to the HPC scheduler:

qsub launch_nf-core_sarek_trio.pbs

Monitoring the Run

qjobs

to check on the jobs, you are running. Nextflow will launch additional jobs during the run.

You can also check the .nextflow.log file for details on what is going on.

Once the pipeline has finished running - Assess the QC report:

NOTE: To proceed, you need to be on QUT’s WiFi network or signed via VPN.

To browse the working folder in the HPC type in the file finder:

...

Evaluate the nucleotide distributions in the 5'-end and 3'-end of the sequenced reads (Read1 and Read2). Look into the “MultiQC” folder and open the provided HTML report.

Items to check:

• The overall quality of the experiment and reads. Look at the “Sequence Quality Histogram” plot. For example, if Phred assigns a quality score of 30 to a base, the chances that this base is called incorrectly are 1 in 1000. Phred quality scores are logarithmically linked to error probabilities.

• Assess QC reports (FastQC and MultiQC) to define how many nucleotides should be trimmed from the 5'-end and/or 3-end regions of the FASTQ reads (see Case 3 below).

Exercise 3: Healthy vs. disease liver samples

Copy and paste the code below to the terminal:

cp $HOME/workshop/data/samplesheet.csv $HOME/workshop/RNAseq/run3_RNAseq
cd $HOME/workshop/RNAseq/run3_RNAseq
pwd

• Line 1: Copy the samplesheet.csv file to the working directory

• Line 2: move to the working directory

• Line 3: print working directory → verify the folder location

Copy the PBS Pro script to run the nf-core/rnaseq pipeline:

cp $HOME/workshop/scripts/launch_nf-core_RNAseq_pipeline.pbs $HOME/workshop/RNAseq/run3_RNAseq

Adjusting the Trim Galore (read trimming) options

Print the content of the launch_RNAseq.pbs script:

cat launch_nf-core_RNAseq_pipeline.pbs

#!/bin/bash -l

#PBS -N nfRNAseq

#PBS -l select=1:ncpus=2:mem=4gb

#PBS -l walltime=48:00:00

#work on current directory

cd $PBS_O_WORKDIR

#load java and set up memory settings to run nextflow

module load java

export NXF_OPTS='-Xms1g -Xmx4g'

nextflow run nf-core/rnaseq --input samplesheet.csv \

        --outdir results \

...

.

...

        --genome GRCm38-local \

        -profile singularity \

        --aligner star_salmon \

        --extra_trimgalore_args "--quality 30 --clip_r1 10 --clip_r2 10 --three_prime_clip_r1 1 --three_prime_clip_r2 1 "

Submitting the job

qsub launch_nf-core_RNAseq_pipeline.pbs

Monitoring the Run

qjobs

Outputs

The pipeline will produce two folders, one called “work,” where all the processing is done, and another called “results,” where we can find the pipeline's outputs. The content of the results folder is as follows: