Neanderthals, the closest relatives of modern humans, may have gone extinct approximately 39,000 years ago, but their legacy endures. Today, traces of Neanderthal DNA are found in most people, thanks to interbreeding with Homo sapiens.
Recent groundbreaking research has provided the most accurate timeline for this interbreeding. The interaction, which peaked around 47,000 years ago, has significantly influenced the human genome, affecting traits such as skin pigmentation, metabolism, and immune response.
Scientists have utilized ancient DNA from Homo sapiens individuals who lived around 45,000 years ago to narrow down the timeline of interbreeding.
One group studied six individuals’ genomes from Ranis, Germany, and Zlaty kun, Czech Republic. Their findings, published in Nature, indicate interbreeding occurred between 49,000 and 45,000 years ago.
Another study, published in Science, analyzed genomes of 300 modern and ancient humans, estimating the interaction occurred between 50,500 and 43,500 years ago.
Both studies highlight that interbreeding was not a single event but an extended period of genetic exchange over several generations.
Neanderthal DNA has left a lasting impact on modern humans:
Skin pigmentation: Genes influencing skin color were shaped by Neanderthal inheritance.
Immune system: Neanderthal genes enhanced immune defenses, with some variants protecting against coronaviruses like the one responsible for COVID-19.
“Neanderthals were living outside Africa for thousands of years before modern humans arrived, and they were presumably adapted to the climate and pathogens outside Africa. Thus, some of their genes may have been beneficial to modern humans,” said Priya Moorjani, a population geneticist at the University of California, Berkeley.
While some Neanderthal genes proved advantageous, others were incompatible with the Homo sapiens genome:
Certain regions of human DNA lack Neanderthal ancestry, suggesting harmful genes were weeded out over time.
Though researchers cannot pinpoint the exact locations where interbreeding occurred, the Middle East is considered the most likely site.
Neanderthals, or Homo neanderthalensis, had robust physiques, larger brows, and intelligent behaviors, including:
Creating art and using symbolic objects
Developing complex hunting methods and possibly spoken language
These traits highlight that Neanderthals were not vastly inferior to Homo sapiens in terms of intelligence or adaptability.
The genome data revealed the physical traits of early Europeans who lived around 45,000 years ago:
Dark skin, dark hair, and brown eyes.
This reflects their recent arrival from Africa and the challenges they faced during the Ice Age.
The Ranis and Zlaty kun individuals do not have any living descendants today, marking them as a “lost branch” of the human family tree.
“Marks on the skull hint towards predators, possibly hyenas, to have either attacked her or gnawed on the skull after her death,” said evolutionary geneticist Arev Sümer.
Most modern humans carry 1-2% of Neanderthal DNA, showing their genes persist despite Neanderthals’ extinction.
“Since their DNA persists in present-day humans’ genomes, they are – in a way – alive and well and more successful than ever,” Sümer remarked.
While many theories exist, researchers propose that Neanderthals may have been absorbed into the modern human population rather than being completely wiped out.
The story of Homo sapiens and Neanderthals is one of survival, adaptation, and connection. These findings not only shed light on the timeline and nature of interbreeding but also highlight how this interaction influenced traits that helped humans thrive in new environments.
Neanderthals may be extinct, but their legacy endures in every cell of their modern human descendants.