00.00-D-Apul-RNAseq-reads-FastQC-MultiQC.Rmd

This Rmd file will download raw RNA-seq FastQs for A.pulchra and evaluate them using FastQC and MultiQC(Ewels et al. 2016).

1 Create a Bash variables file

This allows usage of Bash variables across R Markdown chunks.

{
echo "#### Assign Variables ####"
echo ""

echo "# Data directories"
echo 'export timeseries_dir=/home/shared/8TB_HDD_02/shedurkin/timeseries_molecular'
echo 'export output_dir_top=${timeseries_dir}/D-Apul/output/00.00-D-Apul-RNAseq-reads-FastQC-MultiQC'
echo 'export raw_fastqc_dir=${output_dir_top}/raw-fastqc'
echo 'export raw_reads_dir=${timeseries_dir}/D-Apul/data/raw-fastqs'
echo 'export raw_reads_url="https://owl.fish.washington.edu/nightingales/E5-coral-time-series/30-1047560508/"'
echo ""

echo "# Paths to programs"
echo 'export fastqc=/home/shared/FastQC-0.12.1/fastqc'
echo 'export multiqc=/home/sam/programs/mambaforge/bin/multiqc'
echo ""

echo "# Set FastQ filename patterns"
echo "export fastq_pattern='*.fastq.gz'"
echo "export R1_fastq_pattern='*_R1_*.fastq.gz'"
echo "export R2_fastq_pattern='*_R2_*.fastq.gz'"
echo ""

echo "# Set number of CPUs to use"
echo 'export threads=40'
echo ""


echo "## Inititalize arrays"
echo 'export fastq_array_R1=()'
echo 'export fastq_array_R2=()'
echo 'export raw_fastqs_array=()'
echo 'export R1_names_array=()'
echo 'export R2_names_array=()'
echo ""

echo "# Programs associative array"
echo "declare -A programs_array"
echo "programs_array=("
echo '[fastqc]="${fastqc}" \'
echo '[multiqc]="${multiqc}" \'
echo ")"
echo ""

echo "# Print formatting"
echo 'export line="--------------------------------------------------------"'
echo ""
} > .bashvars

cat .bashvars

#### Assign Variables ####

# Data directories
export timeseries_dir=/home/shared/8TB_HDD_02/shedurkin/timeseries_molecular
export output_dir_top=${timeseries_dir}/D-Apul/output/00.00-D-Apul-RNAseq-reads-FastQC-MultiQC
export raw_fastqc_dir=${output_dir_top}/raw-fastqc
export raw_reads_dir=${timeseries_dir}/D-Apul/data/raw-fastqs
export raw_reads_url="https://owl.fish.washington.edu/nightingales/E5-coral-time-series/30-1047560508/"

# Paths to programs
export fastqc=/home/shared/FastQC-0.12.1/fastqc
export multiqc=/home/sam/programs/mambaforge/bin/multiqc

# Set FastQ filename patterns
export fastq_pattern='*.fastq.gz'
export R1_fastq_pattern='*_R1_*.fastq.gz'
export R2_fastq_pattern='*_R2_*.fastq.gz'

# Set number of CPUs to use
export threads=40

## Inititalize arrays
export fastq_array_R1=()
export fastq_array_R2=()
export raw_fastqs_array=()
export R1_names_array=()
export R2_names_array=()

# Programs associative array
declare -A programs_array
programs_array=(
[fastqc]="${fastqc}" \
[multiqc]="${multiqc}" \
)

# Print formatting
export line="--------------------------------------------------------"

2 Download A.pulchra RNA-seq FastQs

2.1 Download raw RNA-seq reads

Reads are downloaded from https://owl.fish.washington.edu/nightingales/E5-coral-time-series/30-1047560508/

Since sequencing included multiple species, the code will also parse only those that are A.pulchra.

The --cut-dirs 3 command cuts the preceding directory structure (i.e. nightingales/E5-coral-time-series/30-1047560508/) so that we just end up with the reads.

# Load bash variables into memory
source .bashvars

# Make output directory if it doesn't exist
mkdir --parents ${raw_reads_dir}

# Create list of only A.pulchra sample names
sample_list=$(awk -F "," '$6 ~ /^ACR/ {print $5}' ${timeseries_dir}/M-multi-species/data/rna_metadata.csv)

echo ""
echo "${line}"
echo ""
echo "Sample list:"
echo ""
echo "${sample_list}"
echo ""
echo "${line}"
echo ""


# Use printf to format each item for use in wget
formatted_list=$(printf "*%s_*," ${sample_list})

# Remove the trailing comma
formatted_list=${formatted_list%,}

# Output the final wget command
echo ""
echo "${line}"
echo ""
echo "Formatted wget accept list:"
echo ""
echo "wget --accept=\"$formatted_list\""
echo ""
echo "${line}"
echo ""

# Run wget to retrieve FastQs and MD5 files
# Note: the --no-clobber command will skip re-downloading any files that are already present in the output directory
wget \
--directory-prefix ${raw_reads_dir} \
--recursive \
--no-check-certificate \
--continue \
--cut-dirs 3 \
--no-host-directories \
--no-parent \
--quiet \
--no-clobber \
--accept=${formatted_list} ${raw_reads_url}

ls -lh "${raw_reads_dir}"

2.2 Verify raw read checksums

# Load bash variables into memory
source .bashvars

cd "${raw_reads_dir}"

# Checksums file contains other files, so this just looks for the RNAseq files.
for file in *.md5
do
  md5sum --check "${file}"
done

3 FastQC/MultiQC on raw reads

# Load bash variables into memory
source .bashvars

# Make output directory if it doesn't exist
mkdir --parents "${raw_fastqc_dir}"

############ RUN FASTQC ############


# Create array of trimmed FastQs
raw_fastqs_array=(${raw_reads_dir}/${fastq_pattern})

# Pass array contents to new variable as space-delimited list
raw_fastqc_list=$(echo "${raw_fastqs_array[*]}")

echo "Beginning FastQC on raw reads..."
echo ""

# Run FastQC
### NOTE: Do NOT quote raw_fastqc_list
${programs_array[fastqc]} \
--threads ${threads} \
--outdir ${raw_fastqc_dir} \
--quiet \
${raw_fastqc_list}

echo "FastQC on raw reads complete!"
echo ""

############ END FASTQC ############

############ RUN MULTIQC ############
echo "Beginning MultiQC on raw FastQC..."
echo ""

${programs_array[multiqc]} ${raw_fastqc_dir} -o ${raw_fastqc_dir}

echo ""
echo "MultiQC on raw FastQs complete."
echo ""

############ END MULTIQC ############

echo "Removing FastQC zip files."
echo ""
rm ${raw_fastqc_dir}/*.zip
echo "FastQC zip files removed."
echo ""

# Load bash variables into memory
source .bashvars

# View directory contents
ls -lh ${raw_fastqc_dir}

Ewels, Philip, Måns Magnusson, Sverker Lundin, and Max Käller. 2016. “MultiQC: Summarize Analysis Results for Multiple Tools and Samples in a Single Report.” Bioinformatics 32 (19): 3047–48. https://doi.org/10.1093/bioinformatics/btw354.