One widely accepted theory in human evolution is that modern humans evolved in Africa. However, a new analysis of an ancient hominin skull may force us to rethink what we know about our origins.
The Dali skull [Photo by Sheela Athreya]
Fossil evidence has led most scientists believe that modern humans evolved in Africa around 200,000 years ago. Genetic analysis has revealed that all modern humans are descendants of a modern group that left Africa sometime in the last 120,000 years and migrated to different parts of the world. As a result, the majority of our DNA came from this group of ancestors that migrated out of Africa, with some Neanderthal DNA thrown into the mix. However, a skull found in China may cast a shadow of doubt over this long-held narrative.
Now and then, news would break about something that’s always said to have the potential to “rewrite human history” (see this for example). Is this assertion true this time around?
An almost-intact 260,000-year-old skull [Photo by Sheela Athreya]
The Dali skull was discovered 40 years ago in Shaanxi province in China. Despite being 260,000 years old, the skull’s facial features and brain case are still intact. When the skull was first discovered in the late 1970s, researchers thought that the skull belonged to a member of the early human species Homo erectus. However, a new analysis concluded that the skull’s features are too similar to the features of a modern human skull. In fact, the Dali skull has been found to be overwhelmingly similar to two Homo sapiens skulls found in the 1960s in Morocco.
The Homo sapiens skulls found in Morocco
“This was surprising because we expected Dali to exhibit similarities only to other Chinese specimens, particularly the ones that came before it (Homo erectus) and after it (Homo sapiens),” said Sheela Athreya, one of the researchers studying the skull. “But it ended up being more similar to these fossils from North Africa and the Levant, all of which are classified as early Homo sapiens.”
The similarities between the skulls now challenge previously held beliefs about human origins. The Dali skull, according to researchers, has a face like that of a Homo sapiens, but the brain case is relatively primitive. This complicates the origin of our species, which we previously thought to have occurred in a single event from a single point of origin.
“I think gene flow could have been multidirectional, so some of the traits seen in Europe or Africa could have originated in Asia,” Athreya told New Scientist. There’s a possibility that the early modern humans that evolved in Africa weren’t isolated from the other ancestors of modern humans in Eurasia. Groups from Africa and Eurasia may have interbred, suggesting a Eurasian origin as well for modern humans.
Thus, this can explain why a skull found in Asia shares similarities with skulls found in Africa. This can also explain why characteristics that arose in Africa 300,000 years ago can show up again 40,000 years later, this time in Asia. It’s also possible that the features exhibited by the Dali skull may have evolved in China after early Homo sapiens migrated to the area.
Of course, there are skeptics who doubt these claims. However, there’s still a lot of work to be done in order for scientists to be completely sure that these findings do indeed paint an accurate picture of human evolution.
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