Biological Sequence Retrieval

Phase 1: Gene/Organism Disambiguation

1.1 Resolve Identifiers

from tooluniverse import ToolUniverse
tu = ToolUniverse()
tu.load_tools()

# Strategy depends on input type
if user_provided_accession:
    # Direct retrieval based on accession type
    accession = user_provided_accession
    
elif user_provided_gene_and_organism:
    # Search NCBI Nucleotide
    result = tu.tools.NCBI_search_nucleotide(
        operation="search",
        organism=organism,
        gene=gene,
        limit=10
    )

1.2 Accession Type Decision Tree

CRITICAL: Accession prefix determines which tools to use.

1.3 Identity Resolution Checklist

• Organism confirmed (scientific name)
• Gene symbol/name identified
• Sequence type determined (genomic/mRNA/protein)
• Strain specified (if relevant)
• Accession prefix identified → tool selection

Phase 2: Data Retrieval (Internal)

Retrieve silently. Do NOT narrate the search process.

2.1 Search for Sequences

# Search NCBI Nucleotide
result = tu.tools.NCBI_search_nucleotide(
    operation="search",
    organism=organism,
    gene=gene,
    strain=strain,  # Optional
    keywords=keywords,  # Optional
    seq_type=seq_type,  # complete_genome, mrna, refseq
    limit=10
)

# Get accession numbers from UIDs
accessions = tu.tools.NCBI_fetch_accessions(
    operation="fetch_accession",
    uids=result["data"]["uids"]
)

2.2 Retrieve Sequence Data

# Get sequence in desired format
sequence = tu.tools.NCBI_get_sequence(
    operation="fetch_sequence",
    accession=accession,
    format="fasta"  # or "genbank"
)

# GenBank format for annotations
annotations = tu.tools.NCBI_get_sequence(
    operation="fetch_sequence",
    accession=accession,
    format="genbank"
)

2.3 ENA Alternative (for GenBank/EMBL accessions)

# Only for non-RefSeq accessions!
if not accession.startswith(("NC_", "NM_", "NR_", "NP_", "XM_", "XR_")):
    # ENA entry info
    entry = tu.tools.ena_get_entry(accession=accession)
    
    # ENA FASTA
    fasta = tu.tools.ena_get_sequence_fasta(accession=accession)
    
    # ENA summary
    summary = tu.tools.ena_get_entry_summary(accession=accession)

Fallback Chains

Critical Rule: Never try ENA tools with RefSeq accessions (NC_, NM_, etc.) - they will return 404 errors.

Phase 3: Report Sequence Profile

Output Structure

Present as a Sequence Profile Report. Hide search process.

# Sequence Profile: [Gene/Organism]

**Search Summary**
- Query: [gene] in [organism]
- Database: NCBI Nucleotide
- Results: [N] sequences found

---

## Primary Sequence

### [Accession]: [Definition/Title]

| Attribute | Value |
|-----------|-------|
| **Accession** | [accession] |
| **Type** | RefSeq / GenBank |
| **Organism** | [scientific name] |
| **Strain** | [strain if applicable] |
| **Length** | [X,XXX bp / aa] |
| **Molecule** | DNA / mRNA / Protein |
| **Topology** | Linear / Circular |

**Curation Level**: ●●● RefSeq (curated) / ●●○ GenBank (submitted) / ●○○ Third-party

### Sequence Statistics
| Statistic | Value |
|-----------|-------|
| **Length** | [X,XXX] bp |
| **GC Content** | [XX.X]% |
| **Genes** | [N] (if genome) |
| **CDS** | [N] (if annotated) |

### Sequence Preview
```fasta
>[accession] [definition]
ATGCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCG
ATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGA
... [truncated, full sequence in download]

Annotations Summary (from GenBank format)

Alternative Sequences

Ranked by relevance and curation level:

Cross-Database References

Download Options

Formats Available

Direct Commands

# FASTA format
tu.tools.NCBI_get_sequence(
    operation="fetch_sequence",
    accession="[accession]",
    format="fasta"
)

# GenBank format (with annotations)
tu.tools.NCBI_get_sequence(
    operation="fetch_sequence",
    accession="[accession]",
    format="genbank"
)

Related Sequences

Other Strains/Isolates

Protein Products (if applicable)

Retrieved: [date] Database: NCBI Nucleotide

---

## Curation Level Tiers

| Tier | Symbol | Accession Prefix | Description |
|------|--------|------------------|-------------|
| RefSeq Reference | ●●●● | NC_, NM_, NP_ | NCBI-curated, gold standard |
| RefSeq Predicted | ●●●○ | XM_, XP_, XR_ | Computationally predicted |
| GenBank Validated | ●●○○ | Various | Submitted, some curation |
| GenBank Direct | ●○○○ | Various | Direct submission |
| Third Party | ○○○○ | TPA_ | Third-party annotation |

Include in report:
```markdown
**Curation Level**: ●●●● RefSeq Reference
- Curated by NCBI RefSeq project
- Regular updates and validation
- Recommended for reference use

Completeness Checklist

Every sequence report MUST include:

Per Sequence (Required)

• Accession number
• Organism (scientific name)
• Sequence type (DNA/RNA/protein)
• Length
• Curation level
• Database source

Search Summary (Required)

• Query parameters
• Number of results
• Ranking rationale

Include Even If Limited

• Alternative sequences (or "Only one sequence found")
• Cross-database references (or "No cross-references available")
• Download instructions

Common Use Cases

Reference Genome

User: "Get E. coli K-12 complete genome"

result = tu.tools.NCBI_search_nucleotide(
    operation="search",
    organism="Escherichia coli",
    strain="K-12",
    seq_type="complete_genome",
    limit=3
)
# Return NC_000913.3 (RefSeq reference)

Gene Sequence

User: "Find human BRCA1 mRNA"

result = tu.tools.NCBI_search_nucleotide(
    operation="search",
    organism="Homo sapiens",
    gene="BRCA1",
    seq_type="mrna",
    limit=10
)

Specific Accession

User: "Get sequence for NC_045512.2" → Direct retrieval with full metadata

Strain Comparison

User: "Compare E. coli K-12 and O157:H7 genomes" → Search both strains, provide comparison table

Error Handling

Tool Reference

NCBI Tools (All Accessions)

ENA Tools (GenBank/EMBL Only)

Search Parameters Reference

NCBI_search_nucleotide

NCBI_get_sequence