Recent breakthroughs in ancient DNA analysis have provided scientists with invaluable insights into the early migration of Homo sapiens, revealing more about our species’ interactions with Neanderthals.
In a pair of groundbreaking studies, researchers sequenced the oldest known Homo sapiens genomes from human remains discovered in Europe, offering new perspectives on human evolution and the intermingling of our ancestors with Neanderthals.
The remains, found in a cave beneath a medieval castle in Ranis, Germany, have been dated to approximately 45,000 years ago. The bone fragments, representing six individuals—including a mother, daughter, and distant cousins—are part of a population of early Homo sapiens who lived in Europe long before the Neanderthals’ extinction. These genomes revealed that these early humans carried traces of Neanderthal ancestry, confirming that Homo sapiens and Neanderthals interbred during their encounters.
For years, scientists knew that humans and Neanderthals shared genetic material, but pinning down the specifics of when and how often these interbreeding events occurred was a challenge. The new genomic evidence narrows the timeline significantly, suggesting that Homo sapiens intermingled with Neanderthals between 49,000 and 45,000 years ago. This period, spanning about 7,000 years, marked a crucial chapter in human history when early humans from Africa encountered Neanderthals living across Europe and western Asia.
The studies also shed light on the genetic legacy passed down from these interactions. Neanderthal DNA, particularly variants linked to immune functions, skin pigmentation, and metabolism, became advantageous for Homo sapiens adapting to the harsh climates of Ice Age Europe. This genetic inheritance, still detectable in modern humans today, likely played a role in the survival of our ancestors in new environments.
One of the most striking findings is that Neanderthal ancestry was concentrated in specific regions of the human genome, with some variations providing clear advantages for survival. However, not all Neanderthal genes were beneficial. Certain regions, particularly on the X chromosome, showed signs of negative selection, as hybrid individuals carrying those genes may have faced issues like infertility or disease susceptibility.
The study also highlighted the genetic similarities among the early humans in Ranis and a woman from the Czech Republic, whose remains were connected to the Ranis group. This suggests that the individuals were part of a small, closely-knit population, likely numbering just a few hundred people, that lived in scattered bands across Europe.
These studies offer a refined understanding of when Homo sapiens first left Africa and began settling in Europe. According to the researchers, by around 43,500 years ago, most of the migration out of Africa had already taken place. The evidence also supports the idea that modern humans’ expansion was a gradual process, with interbreeding with Neanderthals occurring along the way.
Despite these advances, questions remain about the full extent of early human migration. The disparity in Neanderthal ancestry between populations in East Asia and Europe, as well as the lack of Neanderthal DNA in some regions, continues to puzzle scientists. Ongoing research and the discovery of more ancient genomes may provide answers to these lingering mysteries.
Overall, these studies offer a powerful new lens through which to understand the ancient past. The genomes recovered from Ranis and other sites in Europe help piece together the complex story of how Homo sapiens spread across the globe, met Neanderthals, and ultimately evolved into the modern human population we know today.
CNN, the New York Times, and the Wall Street Journal contributed to this report.
