Previous estimates by Weiss and Maruyama (1976) and Rouhani (1989) of the time that an advantageous gene would take to disperse throughout hominid populations in the Pleistocene were considered to support the multiregional and single origin theories of the origin of modern humans, respectively. With the addition of some long-range gene flow, current simulations indicate that this dispersal could occur in 4000 generations, or in about 80,000 years. However, with a mutation rate of 10(-7) to mutants with the same selective advantage, such mutants would occur in populations before the 1 original mutant could disperse over this large area. The importance of gene flow in maintaining the species seems to be overemphasized.