identifier: METPO:1000430 label: GC mid1 definition: A GC-content phenotype with genome-wide GC composition above approximately 66.3% (the METPO `GC_>66.3` bin; note that the upstream label 'mid1' does not match this high-end 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_>66.3 synonym_type: RELATED_SYNONYM source: metpo.owl evidence: - reference: DOI:10.1186/1471-2148-10-374 snippet: GC-biased gene conversion notes: Bacterial-GC-content evolution review supports GC-biased gene conversion as the mechanism elevating GC content into the high range. causal_graphs: - graph_id: gc_mid1_high_gc_bin title: GC-mid1 (METPO >66.3%) high-GC bin description: DOI-backed graph linking strong GC-biased gene conversion to a GC content above ~66.3% (the threshold encoded by the METPO synonym GC_>66.3 on this record). nodes: - node_id: gc_mid1_trait label: GC mid1 node_type: TRAIT grounding: METPO:1000430 description: GC content above ~66.3% (per METPO synonym GC_>66.3). - 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: strong_gbgc label: strong GC-biased gene conversion node_type: BIOLOGICAL_PROCESS description: Recombination-associated process strongly favoring GC alleles that elevates genome-wide GC content into the high range. - node_id: nhej_pathway label: NHEJ pathway (Ku, LigD) node_type: PATHWAY description: Non-homologous end joining double-strand-break repair pathway (Ku, LigD); KEGG ko03450. - node_id: high_dsb_rate label: high double-strand break rate node_type: BIOLOGICAL_PROCESS description: Elevated rate of DNA double-strand break formation that may select for increased GC content. - node_id: drr_system_composition label: DNA replication and repair (DRR) system composition node_type: PATHWAY description: Composition of DRR pathways (BER/NER/MMR/HR/NHEJ/TLS) whose KEGG-ortholog profile correlates with genomic GC. - node_id: nhej_end_joining_efficiency label: NHEJ end-joining efficiency node_type: MOLECULAR_FUNCTION description: Efficiency of NHEJ end-joining via stabilized short overhang / microhomology pairing. edges: - subject: strong_gbgc predicate: produces object: gc_mid1_trait description: Strong GC-biased gene conversion yields high genome-wide GC composition. evidence: - reference: DOI:10.1186/1471-2148-10-374 snippet: GC-biased gene conversion notes: Supports GC-biased gene conversion as the driver of high-GC composition. predicate_id: METPO:2000202 - subject: gc_mid1_trait predicate: is a object: gc_content description: GC mid1 is a quantitative bin of the GC-content phenotype. evidence: - reference: DOI:10.1038/nrg2358 snippet: GC content notes: Supports the >66.3% bin as a value within the GC-content distribution. predicate_id: rdfs:subClassOf - subject: nhej_pathway predicate: positively correlated with object: gc_mid1_trait description: Ku/NHEJ presence is strongly associated with elevated genomic GC content. evidence: - reference: DOI:10.1371/journal.pgen.1008493 notes: Strong association between Ku presence and elevated GC content; Pearson r=0.54 (p<2.2e-16). Correlational across prokaryotes. - subject: high_dsb_rate predicate: selects for object: gc_mid1_trait description: Higher DSB formation rate selects for increased GC content relative to genomic background. evidence: - reference: DOI:10.1371/journal.pgen.1008493 notes: Sites with higher DSB rates are under selection for increased GC content; proposed unifying driver of GC content across prokaryotes. predicate_id: METPO:2007401 - subject: drr_system_composition predicate: strongly correlated with object: gc_mid1_trait description: DRR-system KEGG-ortholog composition explains a large fraction of genomic GC variance. evidence: - reference: DOI:10.1128/spectrum.02145-22 notes: Linear model using 217 DRR-related KEGG orthologs explains up to 88% of variance in genomic GC (multiple correlation 0.94). - subject: gc_mid1_trait predicate: may increase object: nhej_end_joining_efficiency description: High GC may increase NHEJ repair efficiency by stabilizing short overhangs/microhomologies via extra hydrogen bonds. evidence: - reference: DOI:10.1371/journal.pgen.1008493 notes: High GC via increased hydrogen bonds may stabilize short overhang/microhomology pairing and increase NHEJ efficiency. curation_history: - timestamp: '2026-05-05T01:35:46.817373+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_>66.3) and causal graph linking strong GC-biased gene conversion 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 (4 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2007401×1). llm_assisted: true