Structural variants shape population traits

Single‑gene changes (deletions/duplications) and a few functional single‑letter variants can produce large, population‑specific effects on appearance, metabolism, and disease resistance that polygenic scores do not capture. Mapping these variants with reference datasets (e.g., 1000 Genomes) reveals sharp geographic differences with immediate medical and social relevance. — Recognizing structural and functional variants as distinct from polygenic background changes how we screen for medical risks, talk about ancestry in public policy, and evaluate claims about genetic differences between groups.