We're All Out Of Africa

An analysis of thousands of skulls shows modern humans originated from a single point in Africa and finally lays to rest the idea of multiple origins, British scientists confirmed.

Most researchers agree that mankin spread out of Africa starting about 50000 years ago, quickly establishing Ston Age cultures throughout Europe, Asia & Australia. But a minority have argued, using skull data that divergent populations evovled independently in different areas.

The "multiple origins" school points out that human skulls from around the world have clearly different characteristics, and argues that this proves our species evolved in slightly different forms, more or less simultaneously.

The generic evidence, however, has always strongly supported the single origin theory, and now, results from a study of more than 6000 skulls held around the world in academic collections support this case.

"We have combined our genetic data with new measurements of a large sample of skulls to show definitively that modern humans originated from a single area in Sub-Saharan Africa," said Andrea Manica of the University of Cambridge's Department of Zoology.

Manica & her colleagues wrote in the journal Nature that variations in skull size and shape decreased the further a skull was away from Africa, just like variations in DNA. The decrease reflects the fact that, while the original African population was stable and varied, only a small number of people embarked on each stage of the multi-step migration out of Africa. This effectively created a series of "bottlenecks", which reduced diversity. The highest level of variation was seen in South-eastern Africa the generaly accepted cradle of mankind.