ETE Toolkit 4

Scope

Use ETE 4 to work with an existing tree:

• Read Newick/Nexus, then inspect, annotate, transform, root, prune, and write Newick trees
• Compare topologies and calculate phylogenetic distances
• Find repeated subtree topologies with TreePattern
• Analyze gene trees with PhyloTree
• Query local NCBI or GTDB taxonomy databases
• Explore large trees interactively with SmartView
• Render PNG with SmartView or PNG/PDF/SVG with the optional Qt treeview

ETE does not replace sequence alignment or phylogenetic inference software. For raw sequences, first use MAFFT or another aligner and IQ-TREE 2, FastTree, or another inference tool; then load the resulting tree into ETE.

Current Target

This skill targets ETE 4.4.0, released September 3, 2025 and verified as the current PyPI release on September 30, 2026. Core, phylogeny, local synthetic taxonomy and helper checks target this released package, not unreleased upstream changes. See references/review.md for executed coverage and limitations.

Use https://etetoolkit.github.io/ete/ for ETE 4 documentation. The etetoolkit.org/docs/latest pages are legacy ETE 3 documentation despite the URL name.

Do not silently translate these examples back to ETE 3:

• Package and import: ete4, not ete3
• File input: pass an open file object; use strings for Newick text and do not rely on path-string heuristics retained in ETE 4.4.0
• Newick selection: parser=, not format=
• Node metadata: props, add_prop(), and add_props()
• Iteration: leaves(), descendants(), and related methods return iterators
• Predicates: node.is_leaf and node.is_root are properties, not methods
• Node lookup: tree["name"], not tree & "name"

For porting older code, load references/migration-ete3-to-ete4.md.

Installation

Install the pinned base package:

uv pip install "ete4==4.4.0"