viralQC 0.5.0

A tool and package for quality control of consensus virus genomes.

Install

ViralQC is a tool and package for quality control of consensus virus genomes which uses the nextclade tool, BLAST and a series of internal logics to classify viral sequences and perform quality control of complete genomes, regions or target genes.

From pip

First, install the dependencies:

• Snakemake 7.32
• Ncbi-blast 2.16
• Nextclade 3.15
• Seqtk 1.5
• Python < 3.12

or with micromamba

micromamba install \
  -c conda-forge \
  -c bioconda \
  "python>=3.8.0,<3.12.0" \
  "snakemake-minimal>=7.32.0,<7.33.0" \
  "blast>=2.16.0,<2.17.0" \
  "nextclade>=3.15.0,<3.16.0" \
  "seqtk>=1.5.0,<1.6.0"

Then, install viralQC

pip install viralQC

From Source

git clone https://github.com/InstitutoTodosPelaSaude/viralQC.git
cd viralQC

Dependencies

micromamba env create -f env.yml
micromamba activate viralQC

viralQC

pip install .

Check installation (CLI)

vqc --help

Usage (CLI)

get-nextclade-datasets

This command configures local datasets using nextclade. It is necessary to run at least once to generate a local copy of the nextclade datasets, before running the run-from-fasta command

vqc get-nextclade-datasets --cores 2

A directory name can be specified, the default is datasets.

vqc get-nextclade-datasets --cores 2 --datasets-dir <directory_name>

get-blast-database

This command configures local blast database with all ncbi refseq viral genomes. It is necessary to run at least once to generate a local blast database, before running the run-from-fasta command.

vqc get-blast-database --cores 2

A output directory name can be specified, the default is datasets.

vqc get-nextclade-datasets --cores 2 --output-dir <directory_name>

run-from-fasta

This command runs several steps to identify viruses represented in the input FASTA file and executes Nextclade for each identified virus/dataset.

run-from-fasta

vqc run-from-fasta --sequences-fasta test_data/sequences.fasta

Some parameters can be specified:

• --output-dir — Output directory name. Default: output
• --output-file - File to write final results. Valid extensions: .csv, .tsv or .json. Default: results.tsv
• --datasets-dir — Path to the local Nextclade datasets directory. Default: datasets
• --ns-min-score — Minimum score used by the Nextclade sort command. Default: 0.1
• --ns-min-hits — Minimum number of hits for Nextclade to consider a dataset. Default: 10
• --blast-database - Path to store local blast database. Default: datasets/blast.fasta
• --identity-threshold - Percentual identity threshold for BLAST analysis. Default: 0.9
• --cores — Number of threads used in nextclade sort and nextclade run. Default: 1

The output directory has the following structure:

├── <datasets>                    # Output from nextclade sort; sequences for each dataset split into sequences.fa files.
├── datasets_selected.tsv         # Formatted nextclade sort output showing the mapping between input sequences and local datasets.
├── <virus/dataset>.nextclade.tsv # Nextclade run output for each identified virus, including clade assignments and QC metrics.
├── unmapped_sequences.txt        # Names of input sequences that were not mapped to any virus on nextclade sort.
├── unmapped_sequences.blast.tsv  # BLAST results for unmapped sequences.
└── viruses.tsv                   # Nextclade sort output showing the mapping between input sequences and remote

Usage (API)

vqc-server

Go to http://127.0.0.1:8000/docs

Development

Install development dependencies and run black into viralqc directory.

pip install -e ".[dev]"
black viralqc