About 40,000 years ago, Neanderthals became extinct. While there were other factors involved, interbreeding with Homo sapiens is cited as one possible cause of their downfall. But, with interbreeding occurring, some Neatherthal genes surviving even in today’s humans, and their closeness on the family tree to modern humans, what caused Neanderthals to perish while Homo sapiens thrived?
Creativity, according to a new study from a team of scientists led by the University of Granada.
This is the fifth paper the team, which includes researchers from Finland and the U.S as well, has published on the topic. It is the first study to examine the genotypic differences among chimpanzees, Neanderthals and modern humans.
Previously, the researchers identified a group of 972 genes linked to personality traits that are responsible for learning and memory. They found that these genes are organized into three specific brain networks that evolved in stages. The oldest network emerged among monkeys and apes about 40 million years ago and is responsible for emotional reactivity. About 2 million years ago, the second network, which is focused on self-control, emerged. Finally, about 100,000 years ago, the network relating to creative self-awareness emerged.
Armed with this data, the scientists took their research a step further in their latest paper published in Molecular Psychiatry. Of the 972 genes, they identified 267 that are absent in both chimpanzee and Neanderthal genomes, but present in Homo sapiens. These genes are linked to creativity—and the researchers believe it’s this genetic series that gave Homo sapiens the edge over Neanderthals 40,000 years ago.
In the new study, the researchers found that while 72% of the emotional reactivity genes were common to all three species, divergence occurred in the younger two brain networks. The team showed that Neanderthals had only 33% of the self-awareness genes and 37% of the self-control genes that Homo sapiens benefited from.
"Thanks to these genes, Homo sapiens enjoyed greater physical fitness than now-extinct hominids, providing them with a superior level of resilience to ageing, injury and disease,” explain the researchers. In fact, they estimate Homo sapiens had 60% to 70% better adaptability than their older cousins.
To test the importance of the Homo sapiens-specific genes, the researchers employed genetic markers, gene expression data and magnetic resonance imaging with artificial intelligence. The results showed one or more genes overexpressed in the core brain regions for human self-awareness, which is strongly associated with human well-being, including the characteristics identified by anthropologists as distinguishing Homo sapiens from other hominids.
The authors hypothesize that creativity encouraged cooperation between individuals in a bid to encourage success among their descendants and their community. This would have set the stage for technological innovation, behavioral flexibility and openness to exploration—all of which were necessary for Homo sapiens to spread across the world more successfully than other human lineages.
"Living longer and healthier lives may have prolonged the period of learning associated with youth and adolescence, which would facilitate the accumulation of knowledge. This is a remarkable characteristic of behaviorally modern humans and an important factor in economic and social success," write the researchers.
The international, interdisciplinary study brought together researchers in artificial intelligence, molecular genetics, neurosciences, psychology and anthropology. They say the results enable new lines of research that can help promote human well-being and increase creativity to overcome critical situations.
Photo: Comparison between Homo Sapiens and Homo Neanderthalensis. Credit: University of Granada