Neanderthals and modern humans likely interbred with each other around 100,000 years ago. It was previously believed that the two species bred with each other around 50,000 years ago but a Neanderthal specimen from Siberia is changing what we thought we once knew. Scientists discovered DNA that is found in modern humans in the Neanderthal specimen. Adam Siepel, a computational biologist from Cold Spring Harbor Laboratory in Cold Spring Harbor, New York, comments about the discovery.
“Instead of leaving fragments of Neanderthal DNA in modern humans, we find fragments of modern human DNA in the Neanderthal genome. Humans and Neandertals must have met considerably earlier than we thought previously”
— PaleoAnthropology+ (@Qafzeh) February 18, 2016
The new evidence discovered by Siepel and his team has been published in the scientific journal Nature. In the Siberian specimen, one percent of its genetic code is the same as what is found in modern humans. This is the first piece of evidence that shows the genes flowed both ways. Previously, Neanderthal DNA has been found in modern humans, but never modern human DNA found in a Neanderthal.
Now that a new timeline has been set for when the two species met, scientists realized that the interaction had to have happened after modern humans migrated out of Africa.
— Live Science (@LiveScience) February 17, 2016
It has been believed that humans did not leave Africa until 60,000 years ago. DNA from Neanderthals has been found in modern humans from every place except Africa. This evidence is now leading to scientists having to say that humans left Africa 40,000 years earlier than once thought. Evidence of this new timeline has been corroborated by discoveries of Homo sapiens’ teeth found in China and the Middle East. The artifacts discovered have been dated to 80,000 to 120,000 years ago. Humans had to have left Africa much earlier than the 60,000 years that was once believed. Co-author of the study published in Nature, Sergi Castellano comments on the topic further.
“We find a rather ancient signal of gene flow from modern humans into the ancestors of Neanderthals from the Altai Mountains in Siberia, suggesting that early modern humans had already migrated out of Africa by the time Neanderthals from Europe moved eastward.”
Interbreeding between two different species is considered to be very hard. At the least, it would lead to genetic defects that would make it difficult for the offspring to continue to breed. Neanderthals (Homo Neanderthalensis) and humans (Homo Sapien) are two different species. With the Siberian specimen having only a small percentage of human DNA, it is proof that this specimen is a few generations removed from the initial mating. Doctor Fred Smith, an anthropologist from Illinois State University, believes that this proves that Neanderthals and modern humans are not two different species.
“It’s another piece of evidence that suggests to me that Neanderthals are not a different species than us,” he says. “They look different, they’re differently adapted, but from my perspective, I don’t believe that they were a different species.”
Doctor Siepel understands why Dr. Smith believes what he does, but Siepel also adds that Neanderthals and modern humans did have trouble reproducing which gives credence to the separate species idea.
“Well, it is clear now that modern humans are part neandertal and neandertals were part modern human, so the classical idea of species as groups incapable of interbreeding is clearly not true in this case,” Siepel says. “There are some indications that neandertal/human hybrids may have had somewhat reduced fertility.”
How do you feel knowing you are part Neanderthal?
[Image Via AP Photo/Martin Meissner]