The pioneering work on the human mtDNA tree by Allan Wilson and colleagues (Cann et al. 1987; Vigilant et al. 1991), after some controversy over the methods and the data (reviewed in Forster et al. 2001), quickly focused both geneticists and anthropologists on the probability of a relatively recent African ancestry for all modern humans some two hundred thousand years ago. At most, some geneticists (Templeton 2002; Harding et al. 1997; Green et al. 2010) and anthropologists (Duarte et al. 1999) argue for a possible minor admixture outside Africa of modern Eurasians with already resident hominins such as Homo neanderthalensis or Homo erectus. Supporting evidence for a recent African origin of humans came from Y chromosome research that demonstrated that the two deepest Y branches, now called A and B, are found exclusively in Africans (Underhill et al. 1997).

The establishment of a recent African origin set the scene for the next major discovery in the quest for unravelling human origins – namely, that humans seem to have been restricted to Africa between two hundred thousand years ago and sixty thousand years ago, and only in the last sixty thousand years have successfully ventured out of Africa to settle the rest of the world. This striking paradox was observed in the first large-scale survey of western, eastern and southern Africa by mtDNA analysis conducted by geneticist Elizabeth Watson.