{"id": "card_gene_ssu_rrna", "kind": "reference", "title": "small-subunit ribosomal RNA — a universal gene (a homolog across the domains)", "body": "small-subunit ribosomal RNA: the RNA core of the small ribosomal subunit (16S in prokaryotes, 18S in eukaryotes). Found in Bacteria, Archaea, Eukaryota - a homologous gene descended from a single ancestral gene in LUCA, so it is the confluence where those lineages meet, the way a cognate is shared across language branches. the molecule Carl Woese used to draw the three-domain tree - universal, slow-changing, in every cell. The homology is attested; the ancestral sequence is a reconstruction (a postulate, not sealed).", "source": {"label": "molecular phylogenetics; universal homologs of LUCA", "url": "", "ref": "stick_genomics_the_genetic_code_verified_and_sealed", "domain": "biology", "authority_tier": "reference"}, "shelf": "codex", "box": "universal_gene", "bands": ["tree of life", "homolog", "universal gene", "ssu_rrna", "biology", "phylogeny"], "subject": "small-subunit ribosomal RNA", "connections": [{"to_card_id": "card_tol_domain_bacteria", "relationship": "builds_on", "evidence": "small-subunit ribosomal RNA: present in Bacteria"}, {"to_card_id": "card_tol_domain_archaea", "relationship": "builds_on", "evidence": "small-subunit ribosomal RNA: present in Archaea"}, {"to_card_id": "card_tol_domain_eukaryota", "relationship": "builds_on", "evidence": "small-subunit ribosomal RNA: present in Eukaryota"}], "author": "engine", "created_at": 0.0, "updated_at": 0.0, "visibility": "public", "lifecycle_stage": "public", "volatility": "permanent", "surface": "secular", "generated": false, "call": "codex.universal.gene", "facets": {"subject": ["biology", "homolog", "phylogeny", "ssu_rrna", "tree of life", "universal gene"]}, "presentation": {"glyph": "•", "kind_label": "universal gene", "by": "molecular phylogenetics; universal homologs of LUCA", "authority": "reference", "posted": "", "standing": ""}, "neighbors": [{"id": "card_tol_domain_bacteria", "title": "Bacteria — a domain of life", "relationship": "builds on", "why": "small-subunit ribosomal RNA: present in Bacteria", "href": "/card/card_tol_domain_bacteria", "resolved": true}, {"id": "card_tol_domain_archaea", "title": "Archaea — a domain of life", "relationship": "builds on", "why": "small-subunit ribosomal RNA: present in Archaea", "href": "/card/card_tol_domain_archaea", "resolved": true}, {"id": "card_tol_domain_eukaryota", "title": "Eukaryota — a domain of life", "relationship": "builds on", "why": "small-subunit ribosomal RNA: present in Eukaryota", "href": "/card/card_tol_domain_eukaryota", "resolved": true}], "house": {"door": "FIND", "kind": "card", "trail": "connections", "seal": "/card/card_gene_ssu_rrna", "next_step": {"do": "follow a connection: what this card rests on, and what rests on it", "door": "FIND", "tool": "card_connections", "params": {"id": "card_gene_ssu_rrna"}}, "ends": "a verdict or a card · the trail · a seal · one next step"}}