README.md

Duplex Sequence Pyspark Processing Pipeline

This takes two paired end FASTQ files and searches for Duplex Sequencing amplicons, then matches valid Duplex Sequencing Duplex Consensus Sequences against CODIS sequences.

1. python3 streamFastqTransform.py -s1 seq1.fastq -s2 seq2.fastq -o sample_spark_input.txt

2. spark-submit dsSeqModel.py -i sample_spark_input.txt -o output_prefix -s sample_name

Creates three output files:

1. output_prefix.txt - A list of all of the DCS and the counts of sequences that support it with the CODIS match
2. output_prefix.vcf - A VCF format list of all DCS and counts.
3. output_prefix_sum.txt - A list of all clans that support a CODIS allele (or a matching sequence in the default CODIS_surrounding.tsv or a similar format file containing other sequences supplied with the -c flag).

Example The repository provides example CODIS_spark_input.txt and CODIS_surrounding.tsv that can be used to run an example analysis with:

spark-submit dsSeqModel.py -i examples/CODIS_spark_input.txt -o CODIS_output -s CODIS -c examples/CODIS_surrounding.tsv

Note: D21S11 is too long for a 156 bp read, so it requires a match count (mc) setting of 2 to match CODIS allele and it will output an incorrect allele count because the read cannot span the full allele sequence.

Requires Pyspark >= 2.x, TRAL, and TRF

Installation

Install Spark https://spark.apache.org/downloads.html

Install TRAL http://elkeschaper.github.io/tral/

pip install TRAL

Install TRF http://tandem.bu.edu/trf/trf.html

Workflow

1. use streamFastqTransform.py in parallel to upload FASTQ files to a HDFS

2. use dsSeqModel.py to analyze files

A Docker repository will be available soon.