Humans may have migrated out of Africa about 60,000 years earlier than believed

Researchers have now suggested that the first migration may have occurred about 130,000 years ago.

They said that the early humans may have followed the southern coast of the Arabian Peninsula to Australia and the west Pacific region, adding that the second wave may have traveled along the northern route nearly 50,000 years ago, LiveScience reported.

Katerina Harvati, a paleoanthropologist at the University of Tubingen in Germany, and her colleagues took into account four competing out-of-Africa models.

Out of the two models that involved a single dispersal - one involved a route northward, up the Nile River valley and then eastward across the northern end of the Arabian Peninsula into Asia; the second model involved a route along the southern coast of the Arabian Peninsula into Asia.

Two other models involved multiple dispersals, with both involving routes along Arabian Peninsula's northern and southern ends - one involved connections and gene flow between these routes, and the other did not.

These models helped researchers to predict how much the genes and skull measurements of different groups in Africa, Asia and Australia diverged from each other given how separated they became by space and time. The researchers then compared the predictions with actual gene and skull data from 10 African, Asian and Australian human populations.

Study lead author Hugo Reyes-Centeno, of the University of Tubingen, said in a statement, said Australian Aborigines, Papuans and Melanesians were isolated after the early dispersal along the southern route.

The study has been published online in the journal Proceedings of the National Academy of Sciences.