ETE Toolkit Skill

Overview

ETE (Environment for Tree Exploration) is a toolkit for phylogenetic and hierarchical tree analysis. Manipulate trees, analyze evolutionary events, visualize results, and integrate with biological databases for phylogenomic research and clustering analysis.

When to Use

• Parsing, traversing, or reformatting tree files (Newick / NHX / PhyloXML / NeXML)
• Pruning, rooting, collapsing, or resolving polytomies in a tree
• Detecting duplication/speciation events and inferring orthologs/paralogs from gene trees
• Querying NCBI Taxonomy (taxid/name translation, lineages, taxonomy trees)
• Producing publication-quality PDF/SVG/PNG tree figures
• Comparing trees (Robinson-Foulds) or analyzing clustering dendrograms

Core Capabilities

ETE exposes six capability areas. Each has detailed, copy-ready code in the references (see Index below).

1. Tree manipulation — I/O across formats, traversal (pre/post/levelorder), topology edits (prune, root, collapse), distances, RF tree comparison.
2. Phylogenetic analysis — alignment linkage, species naming, duplication/speciation detection (Species Overlap or reconciliation), orthology/paralogy.
3. NCBI Taxonomy — local cached DB, taxid↔name translation, lineage retrieval, taxonomy-tree building, tree annotation.
4. Visualization — PNG/PDF/SVG export, rectangular/circular layouts, NodeStyle, Face objects, layout functions, interactive GUI.
5. Clustering analysis — ClusterTree, data-matrix linking, silhouette/Dunn metrics, heatmap views.
6. Tree comparison — Robinson-Foulds (raw + normalized), partition/bipartition analysis, batch pairwise distance matrices.

Core Workflow

The canonical minimal pattern — load, edit, save:

from ete3 import Tree

# Load tree from file (format 1 = with internal node names)
tree = Tree("tree.nw", format=1)

# Prune to taxa of interest, preserving branch lengths
tree.prune(["species1", "species2", "species3"], preserve_branch_length=True)

# Midpoint root
tree.set_outgroup(tree.get_midpoint_outgroup())

# Save
tree.write(outfile="rooted_tree.nw")

For class selection: use Tree/TreeNode for generic topology work, PhyloTree for gene trees and evolutionary analysis, ClusterTree for dendrograms with data matrices, and NCBITaxa for taxonomy queries.

Command-Line Scripts

• scripts/tree_operations.py — stats, format conversion, rerooting, pruning, ASCII view. Example: python scripts/tree_operations.py reroot tree.nw rooted.nw --midpoint
• scripts/quick_visualize.py — rapid PDF/PNG rendering with circular layout, support coloring, and DPI control. Example: python scripts/quick_visualize.py tree.nw out.pdf --mode c --color-by-support

Reference Index

Load the relevant file when detailed information is needed:

• references/api_reference.md — Complete API for all ETE classes/methods (Tree, PhyloTree, ClusterTree, NCBITaxa): parameters, return types, code examples.
• references/workflows.md — Per-task workflow patterns (tree operations, phylogenetic analysis, comparison, taxonomy integration, clustering).
• references/visualization.md — Full visualization guide: TreeStyle, NodeStyle, Faces, layout functions, advanced rendering.
• references/use_cases.md — End-to-end worked use cases (phylogenomic pipeline, batch preprocessing, publication figures, automated multi-tree analysis).
• references/setup_and_troubleshooting.md — Installation, NCBI Taxonomy first-run setup, and troubleshooting (imports, Qt rendering, memory, DB corruption).
• references/newick_and_best_practices.md — Newick/NHX format specifications (0-100) and best-practice checklist.