snakemake-workflows/dna-seq-mtb

A flavor of https://github.com/snakemake-workflows/dna-seq-varlociraptor preconfigured for molecular tumor boards

Overview

Topics:

Latest release: v1.10.0, Last update: 2025-03-06

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Deployment

Step 1: Install Snakemake and Snakedeploy

Snakemake and Snakedeploy are best installed via the Mamba package manager (a drop-in replacement for conda). If you have neither Conda nor Mamba, it is recommended to install Miniforge. More details regarding Mamba can be found here.

When using Mamba, run

mamba create -c conda-forge -c bioconda --name snakemake snakemake snakedeploy

to install both Snakemake and Snakedeploy in an isolated environment. For all following commands ensure that this environment is activated via

conda activate snakemake

Step 2: Deploy workflow

With Snakemake and Snakedeploy installed, the workflow can be deployed as follows. First, create an appropriate project working directory on your system and enter it:

mkdir -p path/to/project-workdir
cd path/to/project-workdir

In all following steps, we will assume that you are inside of that directory. Then run

snakedeploy deploy-workflow https://github.com/snakemake-workflows/dna-seq-mtb . --tag v1.10.0

Snakedeploy will create two folders, workflow and config. The former contains the deployment of the chosen workflow as a Snakemake module, the latter contains configuration files which will be modified in the next step in order to configure the workflow to your needs.

Step 3: Configure workflow

To configure the workflow, adapt config/config.yml to your needs following the instructions below.

Step 4: Run workflow

The deployment method is controlled using the --software-deployment-method (short --sdm) argument.

To run the workflow with automatic deployment of all required software via conda/mamba, use

snakemake --cores all --sdm conda

Snakemake will automatically detect the main Snakefile in the workflow subfolder and execute the workflow module that has been defined by the deployment in step 2.

For further options such as cluster and cloud execution, see the docs.

Step 5: Generate report

After finalizing your data analysis, you can automatically generate an interactive visual HTML report for inspection of results together with parameters and code inside of the browser using

snakemake --report report.zip

Configuration

The following section is imported from the workflow’s config/README.md.

General settings

To configure this workflow, modify config/config.yaml according to your needs, following the explanations provided in the file.

Sample sheet

Add samples to config/samples.tsv. For each sample, the columns sample_name, alias, platform, and group have to be defined.

  • Samples within the same group will be called jointly.
  • Aliases represent the name of the sample within its group (they can be the same as the sample name, or something simpler, e.g. tumor or normal).
  • The platform column needs to contain the used sequencing plaform (one of 'CAPILLARY', 'LS454', 'ILLUMINA', 'SOLID', 'HELICOS', 'IONTORRENT', 'ONT', 'PACBIO’).
  • The ffpe column specifies whether a sample is a ffpe substrate (1) or not (0). ffpe treated normal samples are not supported.

Missing values can be specified by empty columns or by writing NA. Lines can be commented out with #.

Unit sheet

For each sample, add one or more sequencing units (runs, lanes or replicates) to the unit sheet config/units.tsv.

  • Each unit has a unit_name, which can be e.g. a running number, or an actual run, lane or replicate id.
  • Each unit has a sample_name, which associates it with the biological sample it comes from.
  • For each unit, define either one (column fq1) or two (columns fq1, fq2) FASTQ files (these can point to anywhere in your system).
  • Alternatively, you can define an SRA (sequence read archive) accession (starting with e.g. ERR or SRR) by using a column sra. In the latter case, the pipeline will automatically download the corresponding paired end reads from SRA. If both local files and SRA accession are available, the local files will be preferred.
  • Define adapters in the adapters column, by putting cutadapt arguments in quotation marks (e.g. "-a ACGCGATCG -A GCTAGCGTACT").

Missing values can be specified by empty columns or by writing NA. Lines can be commented out with #.

Primer trimming

For panel data the pipeline allows trimming of amplicon primers on both ends of a fragment but also on a single end only. In case of single end primers these are supposed to be located at the left end of a read. When primer trimming is enabled, primers have to be defined either directly in the config.yaml or in a seperate tsv-file. Defining primers directly in the config file is prefered when all samples come from the same primer set. In case of different panels, primers have to be set panel-wise in a seperate tsv-file (the path to that tsv can be set in the config under primers/trimming/tsv). For each panel the following columns need to be set: panel, fa1 and fa2 (optional). Additionally, for each sample the corresponding panel must be defined in samples.tsv (column panel). For single primer trimming only, the first entry in the config (respective in the tsv file) needs to be defined.

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