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Neanderthals And Modern Humans Split Earlier Than Thought

A new study suggests Neanderthals and modern humans split at least 800,000 years ago, which is earlier than what scientists believed before. This research is believed to shed new light on human evolution.

The new study conducted by a UCL academic was published in the journal Science Advances, and it reports results based on analyzed dental evolutionary rates from different hominin species found in Sima de los Huesos, Spain.

Sima de los Huesos is a cave in the Atapuerca Mountains which had been hiding the remains of almost 30 people. Previous research studies dated the site to 430,000 years ago in the Middle Pleistocene era, which researchers say makes it one of the oldest collections of human fossils.

“Any divergence time between Neanderthals and modern humans younger than 800,000 years ago would have entailed an unexpectedly fast dental evolution in the early Neanderthals from Sima de los Huesos,” UCL anthropologist Dr. Aida Gomez-Robles said in a statement. “There are different factors that could potentially explain these results, including strong selection to change the teeth of these hominins or their isolation from other Neanderthals found in mainland Europe. However, the simplest explanation is that the divergence between Neanderthals and modern humans was older than 800,000 years. This would make the evolutionary rates of the early Neanderthals from Sima de los Huesos roughly comparable to those found in other species.”

Researchers say DNA analyses previously suggested that modern humans and Neanderthals, who shared the same genome, split 300,000 to 500,000 years ago. However, these results oppose the previous findings.

Sima de los Huesos hominins are characterised by very small posterior teeth (premolars and molars) that show multiple similarities with classic Neanderthals. It is likely that the small and Neanderthal-looking teeth of these hominins evolved from the larger and more primitive teeth present in the last common ancestor of Neanderthals and modern humans,” Gomez-Robles said.

Researchers also tested dental evidence and now believe the dental shape evolved at similar rates for all hominins, including those with reduced teeth. However, the new study looked at the time when modern humans and Neanderthals may have diverged. Using quantitative data, they were able to measure the evolution of dental shape across hominins.

“The Sima people’s teeth are very different from those that we would expect to find in their last common ancestral species with modern humans, suggesting that they evolved separately over a long period of time to develop such stark differences.”

Researchers say this study is important for the understanding of the divergence between Neanderthals and modern humans and also helps with the identification of Homo sapiens and Neanderthals while ruling out other groups they believe existed at other times.