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Cactus

Cactus is a reference-free whole-genome alignment program, as well as a pangenome graph construction toolkit.

Getting Cactus

• Use the precompiled binaries (Linux X86) or Docker image from the latest release
• See below for details on building from source.

Getting help

Please subscribe to the cactus-announce low-volume mailing list so we may reach out about releases and other announcements.

To ask questions or request help, please use the Cactus GitHub Discussions.

To file a bug report or enhancement request against the code or documentation, create a GitHub Issue.

Align Genomes from Different Species

• See the Progressive Cactus documenation
• Please cite the Progressive Cactus paper when using Cactus. Additional descriptions of the core algorithms can be found here and here.
• Please cite the HAL paper when using HAL tools.

Align Genomes from the Same Species and Build Pangenome Graphs

• See the Minigraph-Cactus Pangenome Pipeline documenatation
• Please cite the Minigraph-Cactus paper.

Acknowledgements

Cactus uses many different algorithms and individual code contributions, principally from Joel Armstrong, Glenn Hickey, Mark Diekhans and Benedict Paten. We are particularly grateful to:

• Yung H. Tsin and Nima Norouzi for contributing their 3-edge connected components program code, which is crucial in constructing the cactus graph structure, see: Tsin,Y.H., "A simple 3-edge-connected component algorithm," Theory of Computing Systems, vol.40, No.2, 2007, pp.125-142.
• Bob Harris for providing endless support for his LastZ pairwise, blast-like genome alignment tool.
• Melissa Jane Hubiz and Adam Siepel for halPhyloP and Phast.
• B Gulhan, R Burhans, R Harris, M Kandemir, M Haeussler, A Nekrutenko for KegAlign, the GPU-accelerated version of LastZ.
• Yan Gao et al. for abPOA
• Heng Li for minigraph, minimap2, gfatools and dna-brnn
• Dany Doerr for GFAffix, used to optionally clean pangenome graphs.
• The vg team for vg, used to process pangenome graphs.
• The authors of Mash
• Andrea Guarracino, Erik Garrison and co-authors for odgi. Make sure to cite odgi when using it or its visualizations.
• Hani Z. Girgis for RED
• Erik Garrison and co-authors for vcfwave. vcflib citation

Installing Manually From Source

Cactus requires Python >= 3.8 along with Python development headers and libraries

Clone cactus and submodules

git clone https://github.com/ComparativeGenomicsToolkit/cactus.git --recursive

Create the Python virtual environment. Install virtualenv first if needed with python3 -m pip install virtualenv.

cd cactus
virtualenv -p python3 cactus_env
echo "export PATH=$(pwd)/bin:\$PATH" >> cactus_env/bin/activate
echo "export PYTHONPATH=$(pwd)/lib:\$PYTHONPATH" >> cactus_env/bin/activate
source cactus_env/bin/activate
python3 -m pip install -U setuptools pip wheel
python3 -m pip install -U .
python3 -m pip install -U -r ./toil-requirement.txt

If you have Docker installed, you can now run Cactus. All binaries, such as lastz and cactus-consolidated will be run via Docker. Singularity binaries can be used in place of docker binaries with the --binariesMode singularity flag. Note, you must use Singularity 2.3 - 2.6 or Singularity 3.1.0+. Singularity 3 versions below 3.1.0 are incompatible with cactus (see issue #55 and issue #60).

By default, cactus will use the image corresponding to the latest release when running docker binaries. This is usually okay, but can be overridden with the CACTUS_DOCKER_ORG and CACTUS_DOCKER_TAG environment variables. For example, to use GPU release 2.4.4, run export CACTUS_DOCKER_TAG=v2.4.4-gpu before running cactus.

Compiling Binaries Locally

In order to compile the binaries locally and not use a Docker image, you need some dependencies installed. On Ubuntu (we've tested on 20.04 and 22.04), you can look at the Cactus Dockerfile for guidance. To obtain the apt-get command:

grep apt-get Dockerfile | head -1 | sed -e 's/RUN //g' -e 's/apt-get/sudo apt-get/g'

Progressive Cactus can be built on ARM cpus including on Mac (with packages installed via Brew), but Minigraph-Cactus is currently X86-only.

To build Cactus, run

make -j 8

In order to run the Minigraph-Cactus pipeline, you must also run

build-tools/downloadPangenomeTools

In order to run cactus-pangenome --vcfwave you may need to then run

export LD_LIBRARY_PATH=$(pwd)/lib:$LD_LIBRARY_PATH

If you want to work with MAF, including running cactus-hal2maf, you must also run

build-tools/downloadMafTools

In order to toggle between local and Docker binaries, use the --binariesMode command line option. If --binariesMode is not specified, local binaries will be used if found in PATH, otherwise a Docker image will be used.