Reference panels decide ancestry claims

An individual's reported ancient ancestry can change dramatically depending on which ancient reference samples and model constraints are used; the same modern genotype can be fit as 'pure' local or as a recent admixture by switching panels or sources. Casual presentation of percentage ancestry (e.g., '100% Roman') therefore often reflects analytic choices, not an immutable truth. — Highlights that popular ancestry statements are model‑dependent, which matters for identity politics, journalism, and policy using genetic claims.