Figure 1: Map showing the two potential dispersal routes out of Africa and hypothetical scenarios for Upper Pleistocene hominin dispersals: (a) 150–100 kya, Homo sapiens first appeared in East Africa [19] and dispersed to Arabia, SE Asia, and Levant after 150 kya [1, 5, 38]; (b) 100–60 kya, Homo sapiens continued to expand from Arabia and from the Levant toward Southeast Asia. The reasons for these dispersals may include range expansion in response to overpopulation, competition, and climate change. Gene flow between Homo sapiens and Neanderthals may have occurred in scenario (a), and some hybrid groups may have spread to South and East Asia afterwards. Scenario (b) also depicts the timing of the purported rapid coastal dispersal from East Africa to Southeast Asia via the SR [11].