Phylogenetic tree toolkit (ETE)

# 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.

## Core Capabilities

### 1. Tree Manipulation and Analysis

Load, manipulate, and analyze hierarchical tree structures with support for:

- **Tree I/O**: Read and write Newick, NHX, PhyloXML, and NeXML formats
- **Tree traversal**: Navigate trees using preorder, postorder, or levelorder strategies
- **Topology modification**: Prune, root, collapse nodes, resolve polytomies
- **Distance calculations**: Compute branch lengths and topological distances between nodes
- **Tree comparison**: Calculate Robinson-Foulds distances and identify topological differences

**Common patterns:**

```python
from ete3 import Tree

# Load tree from file
tree = Tree("tree.nw", format=1)