Version Compatibility

Reference examples tested with: BioPython 1.83+, NCBI BLAST+ 2.15+

Before using code patterns, verify installed versions match. If versions differ:

• Python: pip show <package> then help(module.function) to check signatures
• CLI: <tool> --version then <tool> --help to confirm flags

If code throws ImportError, AttributeError, or TypeError, introspect the installed package and adapt the example to match the actual API rather than retrying.

Sequence Similarity Searches

Advanced methods for finding homologous sequences beyond standard BLAST.

"Find distant homologs" → Use iterative search (PSI-BLAST) or profile HMMs (HMMER) to detect remote sequence similarity that standard BLAST misses.

• CLI: psiblast -query seq.fa -db nr -num_iterations 3 or hmmsearch profile.hmm seqdb
• Python: NcbipsiblastCommandline() (BioPython)