Multiregional Continuity: Hominid populations already in Europe (Neanderthals), China (archaic H. sapiens), SE Asia (H. erectus), Africa (archaic H. sapiens), gradually evolved into modern humans.
No certain area of origin because of gene flow.
ancient DNA contributions to modern gene pool.
Single-Origin Theory: AMH evolved in Africa between 300-150 kya. From Africa they migrated into the rest of the world replacing local populations such as H. erectus, Neanderthals and archaic H. sapiens.
lineages overlap in time in each area.
abrupt changes in archaeological record.
Intermediate Theory?: as AMH radiated from Africa they could interbreed with local populations (Neanderthals, archaic H. sapiens, and H. erectus) and exchange cultures.