Morningness gradient not persistent

Applying modern 'morning‑person' polygenic scores to >12,000 dated ancient genomes from western Eurasia shows no long‑standing northward cline; instead, scores rose toward the present faster at lower latitudes, weakening any north–south association over time. The result challenges simple adaptive stories that equate contemporary geographic clines with persistent historical selection. — This matters because it cautions against reading modern GWAS clines as evidence of long‑term selection and affects debates about genetic explanations for behavioral differences across regions.