Using SplitsTree to Explore Consensus Trees and Networks
Introduction
Note that SplitsTree accepts a range of different types of data (trees,
distances between taxa, and characters), which can be supplied in
several different formats.
The this guide to using SplitsTree focus on a rather limited set of its
functionality
- using SplitsTree to sumarise sets of trees using consensus trees
and networks
- processing sets of trees provided in multi-tree NEWICK/PHYLIP
format files
- exploring consensus networks pre-calculated by SplitsTree stored
in NEXUS format files
When using SplitsTree in this way, the user will notice that there are
many different menus and menu options that are not referred to in this
guide. They are encouraged to explore these options and possibilities,
but should realise that this may cause the descriptions provided below
to no longer be valid.
Getting SplitsTree
SplitsTree is a phylogenetic network viewer and manipulator.
SplitsTree is developed by the same group as Dendroscope. As a result,
there are many similarities in the interfaces of the two packages.
The software can be downloaded from
this site.
Opening a
Multi-Tree NEWICK/PHYLIP Format File
Note that SplitsTree accepts a range of different types of data (trees,
distances between taxa, and characters), which can be supplied in
several different formats
A. Indicate that you want to open a file using either:
- File->Open
- Use the "Open an input file" icon

B. Select the file to be opened using your operating system's menus
You will be presented with the "Tree names" window -
providing a list of the names of the trees contained
in the input file - if these names are not assigned in the file, they
are simply labeled "t1", "t2", "t3" etc. - this window allows you to
change/edit the names of any trees by double-clicking on the names and
editing them using the box that then appears
C. Click "Apply" in the "Tree names" window (to accept the names
assigned by SplitsTree to each of the trees in the input file)
As the input file contained a set of trees in non-NEXUS
format, SplitsTree carries out an appropriate set of default
actions/calculations - in this case simply presenting the first tree
from the file in displayed as an unrooted tree
SplitsTree
Graphical User Interface (GUI)
Main Window
Each file/document opened in SplitsTree is associated with a main
window. The main features/components of such a window are shown in the
image below.

Processing Pipeline Window
Many/most of the calculations you will perform are controlled/initiated
via the "Processing Pipeline" Window - which typically looks similar to
the screenshot show below.
At the top of the window are a set of "Blocks", each of which is
associated with a set of one or more "Tabs". This guide will focus on
using the Method tab of the Trees block.

Calculate a Consensus Tree
- Load a set of trees into SplitsTree
- Trees->Consensus Tree
- In the "Method" tab of the "Trees" block in the "Processing
Pipeline" window make sure the following options are selected:
- "Choose trees transformation": ConsensusTree
- "Method": either Strict or Majority depending
on which kind of consensus tree you want to calculate
- "Edge Weights": count - with this option, the
lengths of the edges/branches on the consensus tree will correspond to
the number of trees in which the split represented by the branch is
found
- Click "Apply" - the consensus tree you have calculated should
then appear in the "Network" tab of the Main Window.
Calculate a Consensus
Network
- Load a set of trees into SplitsTree
- Networks->Consensus Network
- In the "Method" tab of the "Trees" block in the "Processing
Pipeline" window make sure the following options are selected:
- "Choose trees transformation": ConsensusNetwork
- "Threshold": 0.1
- "Edge Weights": count
- Click "Apply" - the consensus network should appear in the
"Network" tab of the Main Window. The length of an edge describes the
number of trees in the initial set that contained the split represented
by the edge.
Inspect the Tree/Network
When working with a reasonably large set of taxa and trees, you will
usually need to view the tree at several different levels of detail to
examine the features of interest to you.
The main tools you will use to examine the networks are:
- dragging the tree around the canvas using mouse left-click and
then drag
- the zoom in
and zoom out
icons from the toolbar
To display the weights associated with all edges/branchs on a tree:
- CTRL-Click a branch/edge to show the Label menu
- Edit->Select All
- Choose "Show Weight" from the Label menu
Format the Tree/Network
A very similar set of options are available to adjust the appearance of
edges/branches etc. as found in Dendroscope
Author: Aidan Budd
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