Human origins are a compelling topic of study, if for no other reason than the fact that any findings tend to apply to everyone alive today. Just the other day, scientists announced the discovery of a new human ancestor that further obscures the evolutionary path between early hominids and their modern descendents. Now, yet another new discovery irons out at least one wrinkle in the story of our expansion: Researchers from the University of Cambridge have determined that the first modern humans made their way out of Africa via a northern route, not a southern one.
“Two geographically plausible routes have been proposed: an exit through the current Egypt and Sinai, which is the northern route, or one through Ethiopia, the Bab el Mandeb strait, and the Arabian Peninsula, which is the southern route,” said Dr. Luca Pagani, of the Wellcome Trust Sanger Institute and the University of Cambridge in the UK. “In our research, we generated the first comprehensive set of unbiased genomic data from Northeast Africans and observed, after controlling for recent migrations, a higher genetic similarity between Egyptians and Eurasians than between Ethiopians and Eurasians.”
The study involved the analysis of gene sequences from six northeast African populations, represented by 100 Egyptians and 125 Ethiopians. Scientists knew that the Middle East was the next route for the earliest humans, but the genetic information points at Egypt being their last destination in Africa before leaving for the Arabian Peninsula.
Whether or not that’s surprising depends on your understanding of geography. 60,000 years ago, when our ancestors began their journey to other parts of the world, technology wasn’t exactly at its nadir – they had no GPS, nor much of an understanding of things like seas and oceans. A quick look at a map suggests that early humans would had to have crossed the Bab el Mandeb strait to reach the Peninsula, which is currently 80 miles across at an average depth of some 600 feet. It’s been suggested that at the time the seas were lower if not completely dry, but if early man took a northern route, it’s possible that water travel was a factor.
Also worth considering for early peoples traveling on foot is access to water. Traveling north, they could have followed the Nile River, giving them easy access to water and everything that comes with it (plants, prey animals, etc.). Upon reaching the fertile delta, they would have found a comfortable place to gather themselves before turning east for new frontiers.
One positive side effect of the research is that there’s now an expansive public database of Egyptian and Ethiopian diversity. “This information will be of great value as a freely available reference panel for future medical and anthropological studies in these areas,” says Dr. Pagani.