Evolution: Getting to know the earliest modern Europeans

Genomic analyses of the oldest known modern human remains in Europe, dated to around 45,000 years ago, provide insights into early human migrations in Europe. The research, published in Nature and Nature Ecology & Evolution, paints the picture of complex and varied population histories for early modern humans in Europe.

The oldest known remains of modern humans in Europe were found in the Bacho Kiro Cave in Bulgaria and have been radiocarbon-dated to between 45,930 and 42,580 years before present. The extent of their interactions with Neanderthals, who were present until around 40,000 years ago, has been unclear. In addition, little is known about how the earliest modern humans in Europe contributed to later populations.

An analysis of nuclear genome sequences from human specimens recovered from Bacho Kiro Cave, reported by Mateja Hajdinjak and colleagues in Nature, sheds light on the ancestry of these individuals and their relationships with present-day humans. The oldest three individuals are found to share more genetic variants with present-day populations from East and Central Asia and the Americas than from western Eurasia. These individuals carried between 3% and 3.8% of Neanderthal DNA, and the distribution of Neanderthal genetic material in these genomes indicates that they may have had Neanderthal ancestors as little as six or fewer generations back. The data suggests that mixing between modern humans and Neanderthals may have been more common than previously thought.

A second paper, published in Nature Ecology & Evolution, reports the genome sequence from a skull of a modern human female individual that is thought to be over 45,000 years old from the site of Zlatý kůň in Czechia. Kay Prüfer and colleagues found that the individual carried 3% Neanderthal ancestry, and belonged to a population that appears not to have contributed genetically to either later European or Asian populations. Although radiocarbon dating of the skull failed due to contamination, the length of the Neanderthal segments in the genome are longer than those observed in the genomes of other early modern humans, suggesting that this individual might be older than 45,000 years in age and that she belonged to one of the earliest modern human populations in Eurasia after the expansion out of Africa.

Together, these findings support previous theories of successive population replacements in Europe.

After the embargo ends, the full papers will be available at: https://www.nature.com/articles/s41586-021-03335-3 and https://www.nature.com/articles/s41559-021-01443-x