FastRoot is a python implementation of a class of 'optimization-based' rooting methods for phylogenetic trees: Minimum Variance (MV), Midpoint (MP), Outgroups (OG), and Root-to-tip (RTT). All rooting methods are linear in time and memory. FastRoot was tested on Linux or MacOS.

Installation

FastRoot needs the following dependencies

• Python3
• treeswift (version 1.1.14)
• cvxopt (version 1.2.5)
• numpy (version 1.19.0)

You can either install from PyPI (i.e. pip) or from source code.

Install using Pip

You need to have Python3 and Pip (in most cases are already installed with Python3, if not, please see https://pip.pypa.io/en/stable/installing/). All the other dependencies of FastRoot will be automatically installed together with the package.

python3 -m pip install FastRoot

Install from source code

1. Download the source code.

   • Either clone the repository to your machine

      git clone https://github.com/uym2/MinVar-Rooting.git

   • or simply download this zip file to your machine and unzip it in your preferred destination.

2. To install, go to the MinVar-Rooting folder.

   • If you have pip, use

      python3 -m pip install .

   • Otherwise, if you have root access, type

      sudo python3 setup.py install

   • If you do not have root access, type

      python3 setup.py install --user

Testing

FastRoot_test.py 

• After you installed FastRoot, run FastRoot_test.py to test if the program installed correctly.
• First, Running tests for FastRoot ... will be printed.
• Next, 12 tests will run.
• If OK is printed last, the tests have passed successfully.

Usage

FastRoot.py [-h] [-i INPUT] [-m METHOD] [-g OUTGROUPS] [-t SMPLTIMES] [-o OUTFILE] [-s SCHEMA] [-f INFOFILE] [-v] [-x MAXITER]

optional arguments:

  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        Input File (default is STDIN)
  -m METHOD, --method METHOD
                        Method (MP for midpoint, MV for minVAR, OG for outgroup, RTT for root-to-tip) (default is MV)
  -g OUTGROUPS, --outgroups OUTGROUPS
                        Specify the outgroups. If specifying a list of outgroups, put them between quotes (i.e. ").
                        Otherwise, specifying a file which containts all the outgroups. Can only be used with -m OG
  -t SMPLTIMES, --smplTimes SMPLTIMES
                        The file containing the sampling times at leaves; to be used with -m RTT
  -o OUTFILE, --outfile OUTFILE
                        Output File (default is STDOUT)
  -s SCHEMA, --schema SCHEMA
                        Schema of your input treefile (default is newick)
  -f INFOFILE, --infofile INFOFILE
                        Save all the logging to this file. Default: print to stderr
  -v, --version         Show FastRoot version and exit
  -x MAXITER, --maxIter MAXITER
                        Maximum number of iterations to run cvxopt

NOTE: FastRoot.py works for a list of trees

Rooting methods

There are 4 rooting methods: minVAR (MV), midpoint (MP), outgroups (OG), and root-to-tip (RTT).

MinVAR Rooting (MV)

• Usage: -m MV
• Root the tree at the point that minimizes the variance of the root to tip distances.

Midpoint Rooting (MP)

• Usage: -m MP
• Root the tree at the midpoint of the longest path between any pair of leaves (i.e. midpoint of the diameter).

Root-to-tip Rooting (RTT)

• Usage: -m RTT -t <SAMPLING_TIMES>
• Optimizes the least squares regression of the root-to-tip time and substitutions.
• The sampling times MUST be defined via -t: a tab-delimited file, with one pair of species-time per line.
• Example file: use_cases/RTT/sampling_times.txt. For example, lines

000009  9.36668
000010  9.36668
000011  11.3667
000012  11.3667

show that leaves 000009 and 000010 are sampled at time 9.36668 while nodes 000011 and 000012 are sampled at time 11.3667.

Note:

• The sampling time for every leaf must be specified.
• These times are assumed to be forward; i.e, smaller values mean closer to the root of the tree.

Outgroup Rooting (OG)

• Usage: -m OG -g <OUTGROUPS>
• Maximizes the number of outgroup to ingroup triplets in the tree (i.e. maximizes the number of triplets of the forms (o,(i,i)) and (i,(o,o)) where i is an ingroup species and o is an outgroup species).
• The outgroups MUST be defined via -g: can either by a file -g <OUTGROUP_FILE> or a list surrounded by quotation marks -g "OUTGROUP1 OUTGROUP2 ...".

Output

FastRoot.py with -o will output to the specified destination. Without -o, it prints the tree to standard output (stdout). The optimal score of each tree (depends on the rooting method) is printed to stderr by default; you can direct it to a file using -f.

Example usage

You can checkout the tutorial for some examples.

Publications

If you find MinVar-Rooting helpful for your research, please cite the following paper

• Mai, Uyen, Erfan Sayyari, and Siavash Mirarab. “Minimum Variance Rooting of Phylogenetic Trees and Implications for Species Tree Reconstruction.” Edited by Gabriel Moreno-Hagelsieb. PLOS ONE 12, no. 8 (2017): e0182238. doi:10.1371/journal.pone.0182238.

Besides, MinVar-Rootig was named MCCV in an independent and simultaneous work by Tria et al. Please also consider citing the following paper

• Domingues Kümmel Tria, Fernando & Landan, Giddy & Dagan, Tal. (2017). Phylogenetic rooting using minimal ancestor deviation. Nature Ecology & Evolution. 1. 0193. 10.1038/s41559-017-0193.