By Catherine Griffin
More than a hundred thousand years ago, our ancient, modern ancestors began to migrate out of Africa. Now, scientists have found new clues when it comes to the route that they took, revealing how humans eventually spread across the world.
In order to better understand human migration, the researchers tested different hypothetical dispersal scenarios. They took into account the geography of migration routes, genetic data and cranial comparisons. In the end, they found that the first wave migration out of Africa started far earlier than previously thought. It actually occurred as early as the late Middle Pleistocene, with a second dispersal to northern Eurasia about 50,000 years ago.
In fact, the researchers found that modern humans spread from Africa to Asia and Europe in several migratory movements. The first ancestors of today’s non-African peoples most likely took a southern route through the Arabian Peninsula as early as 130,000 years ago.
What is more interesting is the fact that a common view of human migration may not be true. Scientists believed that humans living today are descended from a common ancestor population that existed 100,000 to 200,000 years ago in Africa. The decreasing genetic and phenotypic diversity seen in humans at increasing distances from Sub-Saharan Africa was interpreted as evidence of a single dispersal. Yet that may not be the case. Instead, it looks as if there were several dispersals.
“Both lines of evidence-anatomical cranial comparisons as well as genetic data-support a multiple dispersal model,” said Katerina Harvati, one of the researchers, in a news release. The first group of people left Africa about 130,000 years ago and then followed a coastal route through the Arabian Peninsula to Australia and the west Pacific region. Then a second movement that occurred about 50,000 years ago resulted in a population that traveled to northern Eurasia.
The findings reveal a little bit more about the movements of our ancient ancestors. Not only that, but they show how different genetic populations evolved and spread across the world out of Africa.