AP Photo/Prakash Hatvalne
The traditional origin story for modern humans says
that early groups migrated out of Africa 60,000 years
Most non-Africans can trace their origin to those
migrations, but new evidence suggests that humans actually
migrated out of Africa as far back as 120,000 years
Those early groups may have brought tools and culture
with them, and they interbred with other hominin species that
existed at the time.
Tens of thousands of years ago, the first Homo
sapiens — modern humans — started to cross mountains,
deserts, and even oceans to leave Africa, where our species first
evolved, and populate Asia and Australia.
The traditional understanding has been that this “Out of Africa”
movement, as it’s often referred to, happened approximately
60,000 years ago. Researchers still agree that most present day
non-Africans trace the majority of their lineage to the large
migration that occurred then.
But several recent discoveries have found evidence that humans
started migrating into Asia as far back as 120,000 years ago.
These early migrants interbred with other hominin species that
existed at the time, including Neanderthals and Denisovans.
Genetic traces of those early migrant groups can still be found
This new information has challenged the previous understanding of
human migration to the point that it needs to be revised,
according to a new
review of research published in the journal Science.
“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,” Michael Petraglia, an archaeologist at
the Max Planck Institute for the Science of Human History and an
author of the study,
said in a press release. “A later, major ‘Out of Africa’
event most likely occurred around 60,000 years ago or
Rethinking the human origin story
The recent studies evaluated in this new review all suggest that
the story of how humans spread throughout the world is more
complex than researchers had thought.
The first fossils of what we’d consider “modern humans” based on
physical characteristics date back close to 200,000 years. In the
Horn of Africa, archaeologists have found remains
of Homo sapiens at least 195,000 years old.
According to the older model, behaviors like the use of tools
were thought to have been brought from Africa 60,000 years ago
and spread north and east.
But some of these recent discoveries show that “modern” behaviors
like blade use, deep-sea fishing, and cave art existed around the
world before that major migration, and in some cases were
associated with populations from other hominin species. Earlier
dispersals of Homo sapiens and interbreeding with other
populations may have helped spread some of these behaviors.
That also helps explain why today, non-Africans have between 1-4%
Neanderthal heritage and why modern residents of Melanesia have
approximately 5% Denisovan heritage. These early hominin groups
mixed together and spread genetic material and culture amongst
“Indeed, what we are seeing in the behavioral record is that the
spread of so-called modern human behaviors did not occur in a
simple time-transgressive process from west to
east,” Christopher Bae of the University of Hawaii at Manoa,
lead author of the study, said in the press release.