Multiple migrations out of Africa, beginning 120,000 years ago – rather than a single exodus 60,000 years ago – gave rise to the modern population of people, according to new research.

The findings of a major new review of scientific literature published this week in the journal ‘Science’ have turned thinking about the origins of humanity on their head.

Advances in DNA analysis and other fossil identification techniques, particularly regarding discoveries in Asia, are rewriting what was previously thought about how humans populated the globe.

A “plethora of new discoveries” over the past decade has shown that modern humans, or Homo sapiens, reached parts of the Asian continent much earlier than previously thought, the report said.

Homo sapien remains have been found at multiple sites in southern and central China, going back to between 70 000 and 120 000 years ago.

Other fossil discoveries show that modern humans reached South East Asia and Australia prior to 60,000 years ago.

“The initial dispersals out of Africa prior to 60,000 years ago were likely by small groups of foragers, and at least some of these early dispersals left low-level genetic traces in modern human populations,” said Professor Michael Petraglia, a researcher at the Max Planck Institute for the Science of Human History in Germany.

“A later, major ‘Out of Africa’ event most likely occurred around 60,000 years ago or thereafter,” he said.

Recent research has confirmed that this mass migration 60 000 years ago “contributed the bulk of the genetic make-up of present-day non-Africans,” said the report.

These early voyagers interbred with other species, including Neanderthals and Denisovans and one currently unidentified population of pre-modern hominins, in many locations across Eurasia.

Scientists estimate that among modern non-Africans today, one to four percent of the DNA comes from Neanderthals and as much as five percent may be from Denisovans.

“It is now clear that modern humans, Neanderthals, Denisovans and perhaps other hominin groups likely overlapped in time and space in Asia, and they certainly had many instances of interaction,” the study said.

Laurie Nowell
AMES Australia Senior Journalist