Researchers have identified a specific period during which Neanderthals began to interbreed with modern humans, based on the analysis of DNA from early European inhabitants.
A study published on Thursday reveals that the interbreeding occurred more recently than earlier estimates suggested, as indicated by the examination of the oldest known genomes from early modern humans in Europe.
The interbreeding is believed to have taken place between 45,000 and 49,000 years ago, suggesting that these two genetically distinct populations coexisted on the European continent for a minimum of 5,000 years.
Radiocarbon dating of bone fragments from Ranis, Germany, revealed a 2.9% Neanderthal ancestry, which the authors attribute to a singular interbreeding event that is common among all non-African populations.
According to the researchers, this interbreeding event likely occurred approximately 80 generations prior to the existence of those individuals.
The Ranis group also represents the earliest known family units, as noted by Arev Sumer, a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and co-author of the study, during a news conference on Wednesday. Among the group, six individuals were found to be closely related, including a mother and her daughter.
One People
The results suggest that the ancestors of all currently sequenced non-African early humans belonged to a shared population during this period, which extended from present-day Great Britain to Poland, as stated by Johannes Krause, a biochemist at the Max Planck Institute for Evolutionary Anthropology and co-author of the research, during the news conference.
“This was quite unexpected, as modern humans had only recently migrated from Africa a few thousand years earlier and had arrived in this northern region of Europe, where the climate was significantly colder than it is today,” Krause remarked. “It was during the height of the Ice Age.”
Previous studies of early human groups in Europe indicated very few instances of interbreeding between Neanderthals and Homo sapiens, according to the paper.
The groups were represented by individuals from the Bacho Kiro region in Bulgaria and a woman named Zlaty kun from Czechia, who is thought to be part of one of the earliest populations to separate from the “Out-of-Africa” lineage. This small group of Homo sapiens departed from the African continent approximately 80,000 years ago.
One Family
Among these two groups, the individuals from Bulgaria indicate two instances of interbreeding with Neanderthals, whereas Zlaty kun’s lineage points to a single instance of such mixing, as noted in the research.
Zlaty kun exhibited a fifth- or sixth-degree genetic connection with two individuals from the Ranis group, as stated by Sumer, who mentioned that the Ranis group comprised a small population that has no living descendants today.
According to Krause, Neanderthals are believed to have gone extinct around 40,000 years ago.
These findings provide researchers with a more accurate timeframe for when these mixing events occurred, along with deeper insights into the demographics of early modern humans and the initial migrations out of Africa, as highlighted in the study.
Further investigation is required to understand the events that transpired following the Out-of-Africa migration and the earliest movements of modern humans throughout Europe and Asia, Sumer emphasized.
