fastreer

Generate phylogenetic trees and distance matrices from VCF or FASTA genomic data.

1.1k|257|Updated Feb 25, 2026
One-click install
npx skills add https://github.com/ClawBio/ClawBio --skill fastreer
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: fastreer
Source: https://github.com/ClawBio/ClawBio/tree/main/skills/fastreer
Command: npx skills add https://github.com/ClawBio/ClawBio --skill fastreer

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires fastreer.

What problem does it solve?

Building phylogenetic trees from genomic variant data normally requires awkward multi-step conversions (VCF to PLINK to distance matrix to external tree software) with no unified output. This Skill converts a VCF or FASTA file directly into a Newick tree or PHYLIP distance matrix in one command, with optional bootstrap support and windowed analysis.

Core Features & Use Cases

  • VCF2TREE / VCF2DIST: Compute cosine dissimilarity between samples from genotype data and build hierarchical clustering trees or export PHYLIP distance matrices, with optional bootstrap replicates.
  • FASTA2DIST / DIST2TREE: Compute D2S k-mer distances from FASTA sequences, or convert an existing PHYLIP distance matrix into a Newick tree.
  • Reproducible reporting: Every run writes report.md, result.json, and a reproducibility bundle recording the exact command and environment.
  • Use Case: A population genomics researcher with a 200-sample VCF wants to see how genetically similar the samples are; one command produces a Newick tree ready for FigTree or iTOL plus an interpretation report.

Quick Start

Ask the agent to build a phylogenetic tree from your VCF file, or run the built-in demo with "run the fastreer demo" to see the expected output on synthetic data.

Frequently Asked Questions about fastreer

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I build a phylogenetic tree from a VCF file?▼

Run the VCF2TREE command with your VCF as input; it computes cosine dissimilarity between samples from genotype dosages and applies UPGMA hierarchical clustering to produce a Newick tree. Bootstrap support can be added with the bootstrap flag.

How to compute a distance matrix from FASTA sequences without alignment?▼

Use the FASTA2DIST command, which computes D2S k-mer distances between sequences without requiring alignment. The default k-mer size is 4, adjustable between 3 and 8, and output is a PHYLIP distance matrix.

Does fastreeR require Java to run?▼

Yes, fastreeR is a hybrid Java/Python toolkit and requires Java 11 or later in addition to the fastreer Python package. The skill checks for both before running and exits with a clear error if either is missing.

Why does fastreeR fail or run out of memory on large VCF files?▼

The default JVM heap of 256 MB is insufficient for more than about 500 samples. Increase the memory flag following the rule of roughly 4 times n_samples squared times threads divided by one million MB.

What are the limitations of VCF-based tree building with fastreeR?▼

The VCF must contain GT genotype fields and at least one sample column; variant-only VCFs silently fail. The skill does not perform alignment, variant calling, annotation, or population genetics statistics like Fst or Tajima's D.