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. 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: