Ancient‑DNA plus polygenic‑score time‑series show that the same ancestry component can evolve in different directions and speeds after it spreads; traits like skin pigmentation, height and education‑linked PGS changed within lineages, not only by simple mixing of fixed ancestral 'packages'. The paper models ancestry×time interactions using the AADR and extracts ancestry‑specific slopes in trait PGS.
— This reframes public arguments that try to map present‑day phenotypes directly onto ancient ancestry percentages and cautions against simplistic uses of polygenic scores across groups in social or policy debates.
Uses the Allen Ancient DNA Resource (AADR), computed PGS for pigmentation, height and educational attainment, and estimates ancestry×time interaction slopes to show differing evolutionary rates.