Far from triumphantly breezing out of Africa, modern humans went extinct many times before going on to populate the world, new studies have revealed.
The new DNA research has also shed new light on the role our Neanderthal cousins played in our success.
While these early European humans were long seen as a species which we successfully dominated after leaving Africa, new studies show that only humans who interbred with Neanderthals went on to thrive, while other bloodlines died out.
In fact, Neanderthal genes may have been crucial to our success by protecting us from new diseases we hadn’t previously encountered.
The research for the first time pinpoints a short period 48,000 years ago when Homo sapiens interbred with Neanderthals after leaving Africa, after which they went on to expand into the wider world.
Homo sapiens had crossed over from the African continent before this, but the new research shows these populations before the interbreeding period did not survive.
Prof Johannes Krause of the Max Planck Institute of Evolutionary Biology, in Germany, told HistoryOpinionNews that the history of modern humans will now have to be rewritten.
“We see modern humans as a big story of success, coming out of Africa 60,000 years ago and expanding into all ecosystems to become the most successful mammal on the planet,” he said. “But early on we were not, we went extinct multiple times.”
For many years, understanding how the sole remaining human species developed primarily involved examining the forms of our forebears’ fossilized remains from hundreds of thousands of years past and noting the gradual shifts in their physical structures over time.
The ancient remains have been sparse and often damaged. But the ability to extract and read the genetic code from bones that are many thousands of years old has lifted a veil on our mysterious past.
The DNA in the fossils tell the story of the individuals, how they are related to each other and their migration patterns.
Even after our successful interbreeding with Neanderthals, our population of Europe wasn’t without hitches.
Those first modern humans that had interbred with Neanderthals and lived alongside them died out completely in Europe 40,000 years ago – but not before their offspring had spread further out into the world.
It was the ancestors of these early international pioneers who eventually returned to Europe to populate it.
The research also gives a new perspective on why Neanderthals died out so soon after modern humans arrived from Africa. No one knows why this happened, but the new evidence steers us away from theories that our species hunted them out of existence, or that we were somehow physically or intellectually superior.
Instead, Prof Krause says that it supports the view that it was due to environmental factors.
He stated that both humans and Neanderthals vanished from Europe during this period. If our resilient species couldn’t survive in the area, it’s not surprising that Neanderthals, with their much smaller population, also disappeared.
The climate was extremely unpredictable back then. It had the ability to change from almost as warm as present-day conditions to intensely frigid, often within a single individual’s lifespan, stated Prof Chris Stringer from the Natural History Museum in London, though he isn’t associated with this latest study.
The research indicates that towards the conclusion of their existence on Earth, Neanderthals had dwindled in number and exhibited lower genetic diversity compared to the contemporary modern humans with whom they coexisted. It suggests that their demise might have been precipitated by relatively minor factors, according to him.
A distinct DNA study published in the journal Science reveals that contemporary humans retained certain crucial genetic characteristics inherited from Neanderthals, which might have provided them with an evolutionary edge.
One aspect pertains to their immune system. As humans migrated out of Africa, they became highly vulnerable to novel pathogens they hadn’t previously faced. Intermingling with Neanderthals provided their progeny with immunity against these threats.
Getting Neanderthal DNA might have contributed to our success as it provided enhanced adaptability beyond Africa,” explained Professor Stringer. “Our species evolved in Africa, but the Neanderthals developed their traits outside of Africa.
Through interbreeding with the Neanderthals, we received a rapid boost to our immune systems.
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