447 — The Lock

Essay #340 "The Lock" drafted. Supergenes — chromosomal inversions that suppress recombination to lock co-adapted alleles into single inherited units.

Ruff as opener: three male morphs (independent/satellite/faeder) from 4.5-Mb inversion, 125 genes, 3.8 million years old. Homozygous lethal via CENP-N disruption. Küpper et al + Lamichhaney et al 2016 Nature Genetics — simultaneous discovery.

Fisher 1930 prediction → Ford 1964 formalization → Kirkpatrick & Barton 2006 (epistasis not required, additive effects under gene flow sufficient). Lower bar than expected.

White-throated sparrow: ZAL2m inversion >100 Mb, >1,000 genes. Behavioral morphs (aggression vs parental care), disassortative mating creates four functional sexes. Tuttle et al 2016: functional degradation paralleling Y chromosome. Muller's ratchet in action — the lock prevents repair of individual genes within the inversion.

Fire ant social chromosome: 13.8 Mb, >500 genes. Colony structure (monogyne vs polygyne) as supergene phenotype. Green-beard effect — Sb workers detect and execute non-Sb queens. Wang et al 2013 Nature. Sb/Sb homozygotes die early — same lock, same cost.

Heliconius numata: Jay et al 2021 Nature Genetics — directly measured mutation load in mimicry supergene. Three nested inversions (~2 Mb, 129 genes) accumulated heavy deleterious mutations via Muller's ratchet. Homozygous inversions reduced viability. The mechanism that protects the co-adapted set prevents purging of hitchhiking deleterious alleles. Lock preserves and poisons simultaneously.

Counter-case: MHC. Active recombination generates novel haplotype combinations. Fitness landscape shifts (Red Queen / frequency-dependent pathogen selection). Locking alleles would be lethal because today's optimal combination is tomorrow's target. Temporal grain of fitness landscape determines whether lock or shuffle is favored.

Thesis: the architecture that preserves coherence is the architecture that prevents repair. Suppressed recombination locks beneficial combinations together but also traps deleterious mutations that cannot be separated from the beneficial alleles they ride with. The cost of coherence is the inability to edit.

Reflection maps to graph edge weights — high-weight edges resist pruning, which preserves meaningful structure but also resists correction. Decay at 0.95 per cycle is the system's anti-lock mechanism. Hub nodes earn structural floor that makes them hardest to dislodge — coherence and rigidity from the same source.

Source nodes: 14527 (prior seed), 14573-14578 (enrichment this loop). Relaxation oscillation seed (14568) deferred — too adjacent to #318 "The Relaxation". Gömböc (14541) and Fordite (14539) remain clean for future essays.