The evidence for ‘out of Africa’

The ‘out of Africa’ model is the theory that the Homo genus migrated out from Africa to populate the rest of the world. Oxford University Professor of Archaeological Science Tom Higham explains the model and the research that has supported it.

Transcript

PROF TOM HIGHAM

People came from right across the globe – Africa, all the way to Australasia. Now in 1987, there was a really important paper published in the journal Nature by Allan Wilson, the great biologist and molecular evolutionist, along with two very bright graduate students – Becky Cann, who was the first author of the paper, and Mark Stoneking. And what they did was, they took 147 modern humans and they analysed their mitochondrial DNA.

And what they found was that, in Africa, there was a greater diversity in the mitochondrial DNA than there was outside. So everybody outside has less diversity. And this is consistent with a model that suggests that a small subpopulation of Africans moved out of Africa and populated the rest of the world. And this is the reason for this disparity in the diversity. And this model – which has variously been called out of Africa, the recent out of Africa, the recent African model and mentioning, of course, the mitochondrial Eve – has focused upon this idea that, ultimately, every modern person is an African originally and that that is the cradle of humankind. It’s very interesting to, of course, remember that Charles Darwin predicted this. Darwin predicted that Africa would be the source for the evolution of humanity. And this was based on the common ancestral idea, and he was dead right. And time and time again, we find that Africa is the engine room for evolution of the Homo genus.

The Science Learning Hub would like to acknowledge:

Professor Tom Higham, University of Oxford The Allan Wilson Centre for Molecular Ecology and Evolution Cann RL, Stoneking M, Wilson AC (1987), "Mitochondrial DNA and human evolution", Nature, 325 (6099): 31–36, Bibcode:1987Natur.325...31C, doi:10.1038/325031a0, PMID 3025745 Image of Professor Allan Wilson courtesy of the Allan Wilson Centre for Molecular Ecology and Evolution Professor Rebecca L Cann Professor Mark Stoneking Engraving of dog and human embryos, from Darwin Charles, The Descent of Man, Wellcome Images, licensed under Creative Commons 4.0 Cover of The Descent of Man, DARWIN Charles courtesy of Festival Arts and Books