Out of Africa

25 Feb 2010

www.physorg.com id186064617 February 22nd ... a special issue of Current Biology is devoted to human beginnings and how genetic evidence, along with archaeological and linguistic research, is being used to bolster the Out of Africa hypothesis - the consensus view. A flavour of the articles can be guaged from an introduction by Colin Renfrew. He says modern humans evolved in Africa around 150,000 years ago - with breathtaking certainty. It is here where human diversity is at it's highest in terms of genetic variation - presumably referring to recent DNA analysis of Bushmen (San) peoples in southern Africa, as well as a diversity of languages. Modern humans migrated Out of Africa, he continues, around 60 to 70 thousand years ago - in order to reach Australia by 50,000 years ago. However, Partha Majumder, in a review of the genetic history of South Asia (one of the following articles) says modern humans migrated Out of Africa 100,000 years ago - pulling the plug on the western dogma. Clearly the subject is not as clear cut as it is currently assumed to be, use of genetics or otherwise. In fact, a study of Neanderthal genetics came to a conclusion not so long ago that ancient genes are subsumed by newer ones over time so it is by no means certain that modern genetic 'evidence' is really 'ancient' - although I assume a residue of older DNA must persist. The San, however, are quite possibly a remnant of the original homo sapiens, and they do appear to exhibit evidence of diversity - and an old study of the Pygmies suggested something similar many years ago (Jean-Pierre Hallet, Pygmy Kitabu, Souvenir Press: 1974).