But in the past decade there has been much debate about the reliability of biological clocks and whether mitochondrial DNA is inherited only from the mother rather than the father. Researchers have looked at other bits of the genome, with varying results for the Eve theory. One study last year of a gene on the X chromosome undermined it, suggesting modern humans had descended from at least two different populations that lived about 200,000 years ago. And yes, he was African and lived around the same time as Eve. Y chromosome studies have also placed the Khoisan among a handful of people with DNA most closely resembling that of the common ancestor of us all.
Genetic studies remain controversial.
And Thorne, in Canberra, has relied on measurements of fossils to come to his conclusion that modern Chinese, Australasians and Europeans each resemble their local predecessors more than they resemble ancient Africans. In particular, the ancestors of Australian Aborigines and ancient people from Java share a suite of anatomical features that are seen only in people from these two regions, he says. These include the overall shape of the skull and pronounced eye ridges. In 1998, Thorne's theory was boosted by research from a team led by Mike Morwood of the University of New England. This would explain how they crossed to Australia.