Sub-Saharan Africans show highest genetic diversity with deepest lineages. Non-Africans derive from small bottlenecked founder group diverging from Africans. Europeans underwent strong selection for lactase persistence and light skin alleles. East Asians selected for EDAR variant altering hair and sweat glands. Tibetans fixed EPAS1 allele from Denisovan hybridization for high-altitude adaptation. Neanderthal introgression aided non-African immune and skin adaptations. Africans lack Neanderthal admixture but show unique selection at malaria resistance loci. Fst genetic distances largest between sub-Saharan Africans and Eurasians. Recent sweeps more intense outside Africa due to new environments. Polygenic selection signals differ starkly by continental ancestry. African populations harbor archaic ghost admixture distinct from Eurasian hominins. Light skin fixation in Europeans genetic not cultural. Dry earwax allele swept in Asians. Selection gradients align with racial geographic origins.