RT Journal Article SR Electronic T1 Out of Africa by spontaneous migration waves JF bioRxiv FD Cold Spring Harbor Laboratory SP 378695 DO 10.1101/378695 A1 Paul D. Bons A1 Catherine C. Bauer A1 Hervé Bocherens A1 Tamara de Riese A1 Dorothée G. Drucker A1 Michael Francken A1 Lumila Menéndez A1 Alexandra Uhl A1 Boudewijn P. van Milligen A1 Christoph Wiβing YR 2018 UL http://biorxiv.org/content/early/2018/07/27/378695.abstract AB Hominin evolution is characterized by progressive regional differentiation, as well as migration waves, leading to anatomically modern humans that are assumed to have emerged in Africa and spread over the whole world. Why or whether Africa was the source region of modern humans and what caused their spread remains subject of ongoing debate. We present a spatially explicit, stochastic numerical model that includes ongoing mutations, demic diffusion, assortative mating and migration waves. Diffusion and assortative mating alone result in a structured population with relatively homogeneous regions bound by sharp clines. The addition of migration waves results in a power-law distribution of wave areas: for every large wave, many more small waves are expected to occur. This suggests that one or more out-of-Africa migrations would probably have been accompanied by numerous smaller migration waves across the world. The migration waves are considered “spontaneous”, as the current model excludes environmental or other factors. Large waves preferentially emanate from the central areas of large, compact inhabited areas. During the Pleistocene, Africa was the largest such area most of the time, making Africa the statistically most likely origin of anatomically modern humans, without a need to invoke additional environmental or ecological drivers.