NCBI Taxonomy - Veterinary

Overview

NCBI (National Center for Biotechnology Information) Taxonomy is a comprehensive database of organism classification and names. For veterinary medicine, NCBI Taxonomy provides standardized species identifiers (TaxIDs), hierarchical taxonomic relationships, and links to genomic databases (GenBank, RefSeq, SRA). This skill covers species lookup, TaxID resolution, and programmatic access via Entrez API.

When to Use

• User looks up species classification, binomial name, or synonyms (e.g., "dog" → Canis lupus familiaris → TaxID 9615)
• User retrieves genomic data for a species (GenBank sequences, reference genomes)
• User performs phylogenetic analysis requiring standardized species nomenclature
• User links veterinary data to genomic research databases
• Keywords: NCBI, taxonomy, TaxID, binomial name, species classification, Entrez, GenBank, RefSeq, SRA

Key Veterinary Species TaxIDs

NCBI Taxonomy Structure

Hierarchical Classification:

Kingdom: Animalia
  Phylum: Chordata
    Class: Mammalia
      Order: Carnivora
        Family: Canidae
          Genus: Canis
            Species: C. lupus
              Subspecies: C. l. familiaris (domestic dog)
                TaxID: 9615

Taxonomic Ranks (from broadest to specific):

• Superkingdom (Eukaryota, Bacteria, Archaea)
• Kingdom (Animalia, Plantae, Fungi)
• Phylum (Chordata, Arthropoda, Mollusca)
• Class (Mammalia, Aves, Reptilia, Amphibia)
• Order (Carnivora, Primates, Rodentia)
• Family (Canidae, Felidae, Equidae)
• Genus (Canis, Felis, Equus)
• Species (lupus, catus, caballus)
• Subspecies (familiaris for domestic dog)

Querying NCBI Taxonomy

Web Interface: https://www.ncbi.nlm.nih.gov/taxonomy

Search Examples:

1. Enter "dog" → Returns Canis lupus familiaris (TaxID 9615) + alternate names
2. Enter "9615" → Returns full taxonomy for domestic dog
3. Enter "feline" → Returns Felis catus, Felis silvestris, etc. (all feline species)
4. Enter "equine" → Returns horses, zebras, donkeys (family Equidae)

Web Results Include:

• Taxonomy browser (full hierarchy)
• Alternate names and synonyms
• Cross-references (GenBank accessions, RefSeq, SRA)
• Number of sequences available in GenBank
• Associated publications

Entrez API Programmatic Access

Entrez Query Syntax: Query NCBI databases including Taxonomy via REST/XML API.

Base URL:

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/

Example 1: Search for Species by Name

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?
  db=taxonomy&term="Canis lupus familiaris"&rettype=json

Response:
{
  "result": {
    "uid": ["9615"],
    "count": "1"
  }
}

Example 2: Fetch Full Taxonomy Record for TaxID

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?
  db=taxonomy&id=9615&rettype=xml

Response: (XML with full taxonomy, rank, lineage, alternate names)

Example 3: Search for All Dog Breeds (Canis lupus variants)

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?
  db=taxonomy&term="Canis lupus[orgn]"&retmax=100&rettype=json

Response: Returns TaxIDs for dog, wolf, dingo, and domestic dog variants

Python SDK (Biopython):

from Bio import Entrez

# Set email (NCBI requires it)
Entrez.email = "[email protected]"

# Search for species
handle = Entrez.esearch(db="taxonomy", term="Canis lupus familiaris")
record = Entrez.read(handle)
taxid = record["IdList"][0]
print(f"TaxID for dog: {taxid}")

# Fetch full taxonomy record
handle = Entrez.efetch(db="taxonomy", id=taxid, rettype="xml")
taxonomy = Entrez.read(handle)
print(f"Lineage: {taxonomy[0]['Lineage']}")
print(f"Rank: {taxonomy[0]['Rank']}")

# Get all names/synonyms
names = taxonomy[0]["OrgName"]["OrgMod"] if "OrgMod" in taxonomy[0]["OrgName"] else []
for name_info in names:
    print(f"Synonym: {name_info['Subname']}")

Linking Taxonomy to Genomic Data

Genomic Database Cross-References:

GenBank: DNA sequences submitted by researchers

• Link: Search GenBank with species TaxID
• Example: Filter by "Canis lupus familiaris [organism]" to retrieve all dog sequences
• Use Case: Find canine tumor suppressor sequences, drug targets

RefSeq: Reference sequence database (non-redundant, curated genomes)

• Link: "Genome" tab in NCBI Taxonomy page
• Current Dog Genome: CanFam3.1 (dog TaxID 9615)
• Example: Download dog reference genome FASTA, align patient tumor WGS to reference

SRA (Sequence Read Archive): Raw sequencing data (fastq, bam files)

• Link: Search by species + disease context
• Example: "Canis lupus familiaris [organism] AND osteosarcoma [disease]"
• Use Case: Download canine osteosarcoma raw RNA-seq data for analysis

Entrez Gene: Gene nomenclature and annotations

• Link: Cross-indexed from taxonomy records
• Example: Query gene symbol "TP53" [organism: Canis lupus familiaris]
• Returns: Dog TP53 gene ID, genomic location (chromosome 5), homology to human/mouse

Workflow Example: Analyze Canine Cancer Gene Expression

1. Start: Patient dog with melanoma
2. Query NCBI Taxonomy: TaxID 9615 (Canis lupus familiaris)
3. Link to RefSeq: Download CanFam3.1 reference genome
4. Find target gene: Query Entrez Gene for "BRAF" [organism: dog]
5. Retrieve sequences: GenBank FASTA for canine BRAF orthologs
6. Download expression data: SRA search "dog melanoma" → retrieve RNA-seq fastq
7. Align & analyze: Map dog tumor RNAseq to reference, quantify BRAF expression
8. Compare to human: Map dog BRAF to human BRAF (NCBI HomoloGene)
9. Translational insight: High BRAF expression in dog → informs human melanoma mechanism

Species Synonyms & Nomenclature Issues

Common Challenges:

• "Dog" ≠ "Canis familiaris" (outdated subspecies classification)
• Modern classification: Canis lupus familiaris (dog is subspecies of gray wolf)
• NCBI Taxonomy lists all names: "domestic dog", "pet dog", "Canis familiaris" (synonym)
• Query flexibility: NCBI accepts any recognized name; returns standardized TaxID 9615

Example: Resolving Nomenclature

Query: "ferret" → NCBI returns multiple:
- Mustela putorius furo (domestic ferret) - TaxID 9646
- Mustela putorius (European polecat, wild ancestor)
- Mustela erminea (stoat, different species)

Veterinarian must verify: Are we discussing domesticated ferret (9646) or wild species?

Taxonomy Updates:

• NCBI Taxonomy is updated regularly as phylogenetic understanding evolves
• Old names may be deprecated; NCBI redirects to current classification
• Example: Some snake species reclassified; old names still searchable with notes

Programmatic Integration for Veterinary AI

Use Case 1: Standardize Patient Species in EHR

def standardize_species(species_name):
    """Convert user input to NCBI TaxID."""
    handle = Entrez.esearch(db="taxonomy", term=species_name)
    record = Entrez.read(handle)
    if record["IdList"]:
        return record["IdList"][0]  # Return TaxID
    else:
        return None  # Not found

# Clinical example:
patient_species = standardize_species("cat")  # Returns 9685
# Store TaxID in database for downstream analysis

Use Case 2: Retrieve Species-Specific Genes for Precision Medicine

def get_orthologous_gene(gene_symbol, target_species_taxid):
    """Find orthologous gene in target species."""
    # Search for gene in target species
    handle = Entrez.esearch(
        db="gene",
        term=f'{gene_symbol} [GENE] AND {target_species_taxid} [ORGN]'
    )
    result = Entrez.read(handle)
    return result["IdList"]

# Example: Find dog BRCA2 to inform hereditary breast cancer screening
dog_brca2 = get_orthologous_gene("BRCA2", 9615)
# Returns list of dog BRCA2 gene IDs for annotation

Use Case 3: Cross-Species Disease Modeling

# Map canine tumor to human disease model
canine_species = 9615  # Dog
human_species = 9606   # Human
mouse_species = 10090  # Mouse

# Download canine osteosarcoma gene signatures (SRA + RNA-seq)
# Align to human osteosarcoma expression data
# Identify conserved oncogenic pathways across species

Rate Limits & Best Practices

Entrez API Limits:

• Without API key: 3 requests per second per IP
• With API key (free registration): 10 requests per second
• Register: https://www.ncbi.nlm.nih.gov/account/

Best Practices:

• Cache results locally; avoid redundant queries
• Use retmax=10000 to batch searches (vs. multiple small queries)
• Implement backoff retry (if rate-limited, wait 1-2 seconds)
• Always provide Entrez.email in scripts (NCBI monitors abuse)
• Batch Entrez calls: query multiple species in single request if possible

Limitations

• Incomplete Metadata: Some organisms lack complete genomic annotation (rare exotic species)
• Taxonomy Instability: Species nomenclature evolves; old publication names may not match current NCBI
• Limited Exotic Data: Well-characterized species (dog, cat, horse) have extensive data; rare species have sparse genomic resources
• Data Quality: Not all GenBank submissions are curated; sequence annotations may contain errors
• This is Reference Only: Taxonomy lookup does not provide clinical guidance; veterinary judgment required for translational decisions

Sources

• NCBI Taxonomy: https://www.ncbi.nlm.nih.gov/taxonomy
• NCBI Entrez: https://www.ncbi.nlm.nih.gov/books/NBK25499/ (E-utilities documentation)
• Biopython Entrez: https://biopython.org/wiki/Documentation (Python API)
• GenBank: https://www.ncbi.nlm.nih.gov/genbank
• RefSeq: https://www.ncbi.nlm.nih.gov/refseq
• SRA: https://www.ncbi.nlm.nih.gov/sra
• Entrez Gene: https://www.ncbi.nlm.nih.gov/gene

Advanced Integration

VetClaw SDK provides convenience wrappers around Entrez API for species lookup and genomic data retrieval. See /sessions/charming-practical-mayer/mnt/OpenVet/vetclaw/vetclaw/sdk/ for Python/TypeScript NCBI Taxonomy client examples.