DNA evidence may have settled a long-standing scientific debate about the exact route early humans took to move out of Africa into Europe and Asia, researchers say.
Leading candidates for the ancient migration are a northern route through Egypt, and a southern exodus through Ethiopia.
An analysis of genetic data from six modern Northeast African populations strongly supports the idea our ancestors moved through Egypt and the Sinai, on a route known as the Levantine corridor through the Middle East, researchers report in the American Journal of Human Genetics.
Modern Egyptians are genetically more similar to non-African Eurasians than people in Ethiopia, suggesting the last stop for humans before leaving Africa was Egypt, say study leader Luca Pagani of the University of Cambridge and the Wellcome Trust Sanger Institute in Britain.
"The most exciting consequence of our results is that we draw back the veil that has been hiding an episode in the history of all Eurasians, improving the understanding of billions of people of their evolutionary history," he says. "It is exciting that, in our genomic era, the DNA of living people allows us to explore and understand events as ancient as 60,000 years ago."
That dating of the migration remains an approximation, the researchers acknowledge, as other genetic studies have implied early humans may have moved out of Africa as long ago as 130,000 years.
Still, they say, their study is strong evidence of the chosen route that led them into Europe and Asia.
"While our results do not address controversies about the timing and possible complexities of the expansion out of Africa, they paint a clear picture in which the main migration out of Africa followed a northern, rather than a southern route," says study co-author Toomas Kivisild of Cambridge's Department of Anthropology and Archaeology.
The findings are in line with other research showing genetic similarities between all non-Africans and Neanderthals living in the Levant corridor at the time.
In addition, 55,000-year-old human fossils have recently been found in Israel, close to the northern migration route.
Not all the questions about humanity's northern migration have been answered by the study, researcher Chris Tyler-Smith admits.
"For example, did other migrations also leave Africa around this time, but leave no trace in present-day genomes? To answer this, we need ancient genomes from populations along the possible routes," he says.
Such genomic data could help answer "intriguing questions of our human origins and migrations," he adds.
