identifier: METPO:1000429 label: GC low definition: A GC-content phenotype with genome-wide GC composition between approximately 42.65% and 57.0% (the METPO `GC_42.65_57.0` bin; note that the upstream label 'low' does not match this mid-range numeric threshold, but the synonym is preserved as the authoritative bin definition). definition_source: DOI:10.1038/nrg2358 trait_category: GENOMICS term_kind: CLASS mapping_status: REVIEWED parent_traits: - METPO:1000127 synonyms: - synonym_text: GC_42.65_57.0 synonym_type: RELATED_SYNONYM source: metpo.owl evidence: - reference: DOI:10.1038/nrg2358 snippet: GC content notes: Bacterial-genome review supports the mid-range GC content as a distinct genomic-composition phenotype. causal_graphs: - graph_id: gc_low_mid_low_gc_bin title: GC-low (METPO 42.65–57.0%) mid-low GC bin description: DOI-backed graph linking moderate mutation bias to a GC content of ~42.65–57.0% (the threshold encoded by the METPO synonym GC_42.65_57.0 on this record). nodes: - node_id: gc_low_trait label: GC low node_type: TRAIT grounding: METPO:1000429 description: GC content ~42.65–57.0% (per METPO synonym GC_42.65_57.0). - node_id: gc_content label: GC content node_type: TRAIT grounding: METPO:1000127 description: Percentage of guanine and cytosine nucleotides in genomic DNA. - node_id: moderate_mutation_bias label: moderate mutation bias node_type: BIOLOGICAL_PROCESS description: Modest mutation-bias balance between AT- and GC-favoring pressures yielding mid-range GC composition. - node_id: dna_repair_defect label: DNA repair defect node_type: BIOLOGICAL_PROCESS description: Loss/impairment of DNA repair pathways (MMR, BER, HR) altering mutation accumulation. - node_id: mutational_spectrum label: mutational spectrum node_type: BIOLOGICAL_PROCESS description: Distribution of mutation types (substitution classes) characterizing a genome. - node_id: cytosine_deamination label: cytosine deamination / C>T bias node_type: BIOLOGICAL_PROCESS description: Spontaneous cytosine deamination driving C>T transitions, the most common mutation type. - node_id: at_enriching_spectrum label: AT-enriching mutation spectrum node_type: BIOLOGICAL_PROCESS description: Mutation spectrum biased toward AT-increasing substitutions (C>A/T enriched, C>G depleted). - node_id: repair_enzyme_bias label: DNA replication/repair enzyme bias node_type: BIOLOGICAL_PROCESS description: Nucleotide biases of DNA replication and repair enzymes contributing to genome base composition. edges: - subject: moderate_mutation_bias predicate: produces object: gc_low_trait description: Moderate mutation-bias balance yields mid-range GC composition. evidence: - reference: DOI:10.1186/1471-2148-10-374 snippet: mutation bias notes: Supports mutation-bias balance as the basis of mid-range GC bins. predicate_id: METPO:2000202 - subject: gc_low_trait predicate: is a object: gc_content description: GC low is a quantitative bin of the GC-content phenotype. evidence: - reference: DOI:10.1038/nrg2358 snippet: GC content notes: Supports the 42.65–57.0% bin as a value within the GC-content distribution. predicate_id: rdfs:subClassOf - subject: dna_repair_defect predicate: causes object: mutational_spectrum description: Defects in DNA repair genes (MMR, BER, HR) create distinctive bacterial mutational signatures. evidence: - reference: DOI:10.1038/s41467-023-42916-w notes: Defects in DNA repair create distinctive mutational signatures attributable to MMR, BER, or HR genes. predicate_id: biolink:causes - subject: cytosine_deamination predicate: shifts toward object: at_enriching_spectrum description: Cytosine deamination / C>T transition bias shifts the spectrum toward AT-enriching substitutions. evidence: - reference: DOI:10.1038/s41467-023-42916-w notes: C>T was the most common mutation type in 69 of 84 SBS spectra, potentially due to cytosine deamination. - subject: at_enriching_spectrum predicate: associated with object: gc_low_trait description: A spectrum enriched for C>A/T and depleted for C>G is associated with lower genomic G+C content. evidence: - reference: DOI:10.1038/s41467-023-42916-w notes: Genomic G+C content negatively correlates with C>A/T proportion and positively with C>G mutations. predicate_id: biolink:associated_with - subject: repair_enzyme_bias predicate: shapes object: gc_content description: Biases of DNA replication/repair enzymes and inter-nucleotide mutation rates shape genomic GC percent. evidence: - reference: DOI:10.3389/fmicb.2024.1412318 notes: Genome GC% depends in part on mutation rates between nucleotides; replication/repair enzymes present biases. curation_history: - timestamp: '2026-05-05T01:35:46.816924+00:00' curator: seed_from_metpo action: SEEDED_FROM_METPO changes: imported from data/raw/metpo.owl (CLASS) llm_assisted: false - timestamp: '2026-05-13T13:00:00-07:00' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added DOI-backed definition (derived from METPO synonym GC_42.65_57.0) and causal graph linking moderate mutation bias to this GC bin. Documented the upstream label-vs-threshold inconsistency. llm_assisted: true - timestamp: '2026-05-20T03:35:30Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000202×1, rdfs:subClassOf×1). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 4 evidence-backed generic edges (5 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (biolink:causes×1, biolink:associated_with×1). llm_assisted: true