{"id": "card_n_8a1d7924121c", "kind": "note", "title": "The genetic clock — mitochondrial Eve and the molecular record", "body": "Mitochondrial DNA passes only mother to child and never recombines, so it is a clean\nmaternal lineage; the Y chromosome does the same for fathers. Mutations accumulate at a roughly\nsteady rate, so counting the differences DATES the common ancestor — 'Mitochondrial Eve' (the\nmost-recent common maternal ancestor, ~150-200 kya) and 'Y-chromosomal Adam' (paternal). Sealed:\nthe human mtDNA genome is 16,569 bp (~4 KB), and two lineages coalesce in ~2N generations\n(https://narrowhighway.com/s/222afa501ad9a65a6cbb50011690b7b5363cc002934bf367eac99bf946b5774b). Honest: Eve and Adam are the most-recent common ancestors of surviving lineages, not\nnecessarily the first humans — yet all maternal lines converging on one woman and all paternal\non one man is real and striking (the names were not chosen idly). Haplogroups chart the\nbranches; ancient DNA now reads them straight from bone. The genetic clock traces the peopling\nof the earth back toward one source. RESONANCE with the linguistic clock; signpost.", "source": {"label": "Concordance assay — 2026-07-09", "url": "https://narrowhighway.com/s/222afa501ad9a65a6cbb50011690b7b5363cc002934bf367eac99bf946b5774b", "ref": "tracing_peoples", "authority_tier": "engine_derived"}, "shelf": "science", "box": "human_origins", "bands": ["mitochondrial dna", "molecular clock", "mitochondrial eve", "y-chromosome", "haplogroup", "coalescence", "ancient dna", "ancestry", "16569"], "connections": [], "author": "engine", "created_at": "2026-07-10T02:23:13.207894+00:00", "updated_at": "2026-07-10T02:23:13.207894+00:00", "visibility": "public", "lifecycle_stage": "public", "volatility": "permanent", "surface": "secular", "metrics": {"paperclips_count": 0, "helpful_count": 0, "not_helpful_count": 0, "cite_count": 0, "walks_through_count": 0, "flagged_count": 0}, "source_hash": "4559a588e82cf4dfefc1e721ec04f7f8c61a989a5643cd3ff1bedbe7d7a8d789"}