/biopython

name: biopython
description: Provides Biopython workflows for sequence manipulation, file parsing (FASTA/GenBank/PDB), phylogenetics, and programmatic NCBI/PubMed access (Bio.Entrez). Supports batch processing, custom molecular-biology pipelines, BLAST automation, structure analysis, and motif analysis.
allowed-tools: Read Write Edit Bash
compatibility: Requires Python 3.10+, NumPy, and Biopython 1.88. Optional plotting requires Matplotlib or ReportLab. Entrez and web BLAST require network access and a contact email; local BLAST, MUSCLE 5, Clustal Omega, and DSSP require separate executables.
license: Biopython License Agreement
metadata:
  version: "1.5"
  last-reviewed: "2026-09-30"
  skill-author: K-Dense Inc.
  openclaw:
    envVars:
    - name: NCBI_EMAIL
      required: false
      description: Email for NCBI Entrez identification (required by NCBI policy for Entrez calls).
    - name: NCBI_API_KEY
      required: false
      description: NCBI API key to raise Entrez rate limits.

Biopython: Computational Molecular Biology in Python

Overview

Biopython is a comprehensive set of freely available Python tools for biological computation. It provides functionality for sequence manipulation, file I/O, database access, structural bioinformatics, phylogenetics, and many other bioinformatics tasks. These examples target **Biopython 1.88** (released 6 August 2026), tested here on Python 3.13. It requires Python 3.10+ and NumPy; Python 3.10 support is deprecated. Upgrade to 1.88 for its `Bio.Nexus` parser security fix, in addition to the Entrez XML fix in 1.87. See the [release notes](https://github.com/biopython/biopython/blob/biopython-188/NEWS.rst). Local example checks and external-service limits are recorded in `references/review.md`; examples requiring user files or external programs are illustrative unless listed there as exercised.

When to Use This Skill

Use this skill when:

• Working with biological sequences (DNA, RNA, or protein)
• Reading, writing, or converting biological file formats (FASTA, GenBank, FASTQ, PDB, mmCIF, etc.)
• Accessing NCBI databases (GenBank, PubMed, Protein, Gene, etc.) via Entrez
• Running BLAST searches or parsing BLAST results
• Performing sequence alignments (pairwise or multiple sequence alignments)
• Analyzing protein structures from PDB files
• Creating, manipulating, or visualizing phylogenetic trees
• Finding sequence motifs or analyzing motif patterns
• Calculating sequence statistics (GC content, molecular weight, melting temperature, etc.)
• Performing structural bioinformatics tasks
• Working with population genetics data
• Any other computational molecular biology task

Core Capabilities

Biopython is organized into modular sub-packages, each addressing specific bioinformatics domains:

1. **Sequence Handling** - Bio.Seq and Bio.SeqIO for sequence manipulation and file I/O 2. **Alignment Analysis** - Bio.Align and Bio.AlignIO for pairwise and multiple sequence alignments 3. **Database Access** - Bio.Entrez for programmatic access to NCBI databases 4. **BLAST Operations** - Bio.Blast for running and parsing BLAST searches 5. **Structural Bioinformatics** - Bio.PDB for working with 3D protein structures 6. **Phylogenetics** - Bio.Phylo for phylogenetic tree manipulation and visualization 7. **Advanced Features** - Motifs, population genetics, sequence utilities, and more

Installation and Setup

Install the current stable Biopython release with an explicit version pin for reproducibility:

uv pip install "biopython==1.88"

For NCBI database access, always set your email address (required by NCBI). For reusable software, set a stable `Entrez.tool` value and register the tool/email with NCBI. For higher rate limits (10 req/s instead of 3 req/s), read only `NCBI_API_KEY` from the environment — do not hardcode keys or load unrelated environment variables:

import os
from Bio import Entrez

Entrez.email = "your.email@example.com"  # required — use your real email
Entrez.tool = "your_tool_name"  # optional but recommended for reusable software

# Optional: register at https://www.ncbi.nlm.nih.gov/account/settings/
if api_key := os.environ.get("NCBI_API_KEY"):
    Entrez.api_key = api_key

Using This Skill

This skill provides comprehensive documentation organized by functionality area. When working on a task, consult the relevant reference documentation:

1. Sequence Handling (Bio.Seq & Bio.SeqIO)

**Reference:** `references/sequence_io.md`

Use for:

• Creating and manipulating biological sequences
• Reading and writing sequence files (FASTA, GenBank, FASTQ, etc.)
• Converting between file formats
• Extracting sequences from large files
• Sequence translation, transcription, and reverse complement
• Working with SeqRecord objects

**Quick example:**

from Bio import SeqIO

# Read sequences from FASTA file
for record in SeqIO.parse("sequences.fasta", "fasta"):
    print(f"{record.id}: {len(record.seq)} bp")

# Convert GenBank to FASTA
SeqIO.convert("input.gb", "genbank", "output.fasta", "fasta")

2. Alignment Analysis (Bio.Align & Bio.AlignIO)

**Reference:** `references/alignment.md`

Use for:

• Pairwise sequence alignment (global and local)
• Reading and writing multiple sequence alignments
• Using substitution matrices (BLOSUM, PAM)
• Calculating alignment statistics
• Customizing alignment parameters

**Quick example:**

from Bio import Align

# Pairwise alignment
aligner = Align.PairwiseAligner()
aligner.mode = 'global'
alignments = aligner.align("ACCGGT", "ACGGT")
print(alignments[0])

3. Database Access (Bio.Entrez)

**Reference:** `references/databases.md`

Use for:

• Searching NCBI databases (PubMed, GenBank, Protein, Gene, etc.)
• Downloading sequences and records
• Fetching publication information
• Finding related records across databases
• Batch downloading with proper rate limiting

**Quick example:**

from Bio import Entrez
Entrez.email =