Humans Moved out of Africa Much Earlier than Previous Estimates

The ancestors of Eurasians left Africa as early as 130,000 years ago, a new study has found.

The study, conducted by researchers at University of Tübingen, found that early humans adopted several migratory routes to move out of Africa and spread to other parts of the world.

For the research, Katerina Harvati and colleagues tested various hypothetical dispersal scenarios. The team accounted for geographical factors, genetic data and information about skull structure. Their study showed that migration happened in waves with the earliest Eurasians leaving Africa some 130,000 years ago. The second wave of migration occurred some 50,000 years back.

The study challenges the idea that people moved out of Africa during a single dispersal period between 50,000 and 75,000 years ago.

"Both lines of evidence -- anatomical cranial comparisons as well as genetic data -- support a multiple dispersal model," said Katerina Harvati.

According to the researchers, the first group took a coastal route to reach Australia and the western pacific region.

"Australian aborigines, Papuans and Melanesians were relatively isolated after the early dispersal along the southern route," said Hugo Reyes-Centeno, first author of the study and member of the Tübingen team, according to a news release.

Other non-African populations are descendants of the latter group that migrated from Africa some 50,000 years back.

For the study, researchers compared human skulls from different parts of the world. They used neutral genetic data and even compared geographical distances associated with each of the several migratory routes proposed by other scientists. Also, they used genetic data to see how populations must have split in different regions of the world.

Why did humans move out of Africa? A leading theory suggests that droughts in East Africa occurring between 135,000 and 75,000 forced people to migrate out of Africa. The team is hopeful that advances in genetic testing will help them fine-tune their research.  

The study, "Genomic and Cranial Phenotype Data Support Multiple Modern Human Dispersals from Africa and a Southern Route into Asia," is published in the journal Proceedings of the National Academy of Sciences.