kcst - k-mer counting sequence typer
kcst predicts species and MLST from assembled sequences or raw reads.
kcst predicts species and multi-locus sequence type from assembled or raw
reads. It does this by comparing the k-mers in the query sequences with those
in the MLST profiles, picking the alleles best covered by the query.
kcst does this 'all in one go'. Instead of first predicting species in
order to pick the applicable MLST scheme, it matches the query across all
MLST schemes at once.
By using a k-mer mapping approach, kcst is very fast. It typically takes
about a second to type one assembled genome. The binary core of
khc (k-mer hit count).
khc can be used standalone to rapidly compute
sequence similarity between a query and a set of subject sequences.
More information: http://io.zwets.it/kcst
Assuming you are on a GNU/Linux system, and you have just cloned
GitHub, here are the steps to run it:
kcstyou need a C++ compiler and GNU
make --versionto check that you have these. Support for gzipped files requires Boost Iostreams (install the
awk, which probably is already on your system (try
gawk --version), or else can be installed via the package manager.
# Compile the khc source code cd src make # Optionally run the unit tests make test
There is no need to install
khcin a specific place, only that for
kcstto find it,
khcmust be on PATH or in the same directory as
# Symlink bin/khc to the compiled binary src/khc # Note: if you cloned the repository, this link will already be present cd bin ln -sf ../src/khc # For convenience in the steps below, put kcst and khc on the PATH # (While in directory ./bin) PATH="$PWD:$PATH"
# khc has self-contained usage instructions khc --help # Example: calculate coverage of ecoli.fsa by k-mers from test.fa.gz cd ../data/examples khc -s -k 15 -c 95 ecoli.fsa test.fa.gz # Example: pipe from stdin zcat test.fa.gz | khc -s -k 15 -c 95 ecoli.fsa
# Construct example database with just ecoli.fsa # (Still in data/examples) ../make-db.sh -f "$PWD" # reads file 'config', writes mlst.* # Perform MLST of test.fa against the example database kcst -d "$PWD" test.fa.gz # After you install the default database (see below), this suffices: kcst test.fa.gz
See the Quick Start above.
khc do not need to be installed in any
specific location. The only requirement is that
kcst can find
on the PATH or in the directory where
kcst itself is located.
You must provide an MLST database for
kcst to work with. The simplest way to
install one is by cloning and importing the database maintained by the Centre
for Genomic Epidemiology (CGE) at DTU Copenhagen, as follows:
# Pick a directory to contain the downloadeded CGE database CGE_MLST_DIR=/your/path/of/choice # Clone the CGE git repository with the MLST database git clone 'https://bitbucket.org/genomicepidemiology/mlst_db.git' "$CGE_MLST_DIR" # Import the database to kcst's default MLST database directory (./data) cd data ./make-db.sh -v -f "$CGE_MLST_DIR" # Note default k-mer size is 15 # Check that the three database files have been created ls mlst.* # should give mlst.db, mlst.cfg, mlst.tsv # Test the database: run MLST on test.fa kcst -v examples/test.fa.gz
You can now remove
CGE_MLST_DIR, or keep it around for pulling future updates:
# Update the CGE repository to the current release CGE_MLST_DIR=/path/where/you/cloned/it cd $CGE_MLST_DIR git pull # Import the database in kcst's data directory cd $(dirname $(realpath $(command -v kcst)))/../data ./make-db.sh -f -v "$CGE_MLST_DIR"
kcst can work with multiple separate databases (see option
instance with different species or k-mer sizes (the default is 15). Refer to
data/README.md for information about importing MLST databases.
kcst - k-mer counting sequence typer
Copyright (C) 2018 Marco van Zwetselaar firstname.lastname@example.org
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.