Epigenetic Drift

Epigenetic drift is the τ-categorical degradation of the chromatin partition D_n with age: methylation patterns erode, histone marks become noisy, chromatin boundaries blur. It is the chromatin-level instance of the aging defect (VI.D43) — accumulated error in the evaluator's filter, not in the underlying ω-germ code.

Categorical invariant. Time-derivative of the epigenetic state; an instance of the aging-defect class (VI.D43) localised at the chromatin partition; preserves code(D)[ω] but degrades D_n fidelity.

Primary registry anchor: VI.D85

Supporting items: VI.D79, VI.D43

1. I.K0 — Universe Postulate
2. VI.D15 — Life Sector
3. VI.D43 — Aging as Defect Accumulation — the parent class
4. VI.D79 — Epigenetic State — the (n, D_n) pair that drifts
5. VI.D85 — Epigenetic Drift — the chromatin-level aging defect

Biomarker: Global hypomethylation with focal hypermethylation at CpG islands; loss of H3K9me3 heterochromatin marks; LINE-1 reactivation; chromatin boundary erosion; Horvath methylation clock signature on ~350 CpG sites.

Measurable range: Horvath clock: predicts chronological age from ~350 CpG methylation values with median error ≈ 3.6 years across most human tissues; second-generation clocks (PhenoAge, GrimAge) predict mortality risk; drift rate ≈ 0.5-1% methylation change per decade at variable CpG sites.

Observation method: Whole-genome bisulfite sequencing across age cohorts; Illumina EPIC methylation array (Horvath/Hannum/PhenoAge clocks); ATAC-seq for accessibility loss; Hi-C for boundary erosion; Yamanaka-factor partial reprogramming as the experimental rejuvenation perturbation.

Calibration anchor: LG-Y02-kinetic-pseudoscalar-channel

Anchor chain:

1. VI.L18 chirality channel
2. DNA D-sugar backbone preserved through drift
3. drift acts on D_n filter only — code(D)[ω] remains chirality-locked
4. epigenetic drift as filter-level decay of chirality-locked decoding

Manuscript reference: manuscript-sources/book-06/part06/ch35-cell-cycle.tex

Status: Not formalized

Related glossary entries

• LG-I07-epigenetic-state Epigenetic State
• LG-Y02-kinetic-pseudoscalar-channel Kinetic Pseudoscalar Channel