# Molecular Clock **Domain:** Molecular Evolution / Time Inference **Doc Type:** Canonical Concept Node **Maturity:** Foundational ## Definition A **molecular clock** estimates evolutionary divergence time from accumulated molecular differences, using assumptions or calibrations about rates of change. ## Evidence Boundary The clock is not perfectly regular. Rates differ across genes, lineages, generations and selective regimes. Contemporary analyses therefore use calibrated and often probabilistic models rather than a single universal tick rate. [[articles/The Evolutionary Roots of Silicon Valley|The Evolutionary Roots of Silicon Valley]] emphasizes the historical importance of Allan Wilson and Vincent Sarich at Berkeley: molecular evidence constrained a fossil-based chronology and demonstrated that inherited sequence stores recoverable temporal information. ## Continuity Context A clock can locate common ancestry without identifying a continuing individual. It measures lineage divergence, not persistence of consciousness. That makes it a central example of the difference between [[wiki/Proof of Descent|Proof of Descent]] and identity. ## Sources / Provenance - UC Berkeley, “1967 — Molecular evolution”: https://www.berkeley.edu/about/history-discoveries/ - Zuckerkandl and Pauling, “Evolutionary Divergence and Convergence in Proteins,” 1965. ## See Also [[wiki/Allan Wilson|Allan Wilson]], [[wiki/Vincent Sarich|Vincent Sarich]], [[wiki/Mitochondrial Eve|Mitochondrial Eve]], [[wiki/Fossil Record|Fossil Record]]