The oldest modern human genome has been reconstructed using 45,000-year-old skull DNA

This skull from the Zlatý kůň cave near Prague belonged to the earliest known modern man in Europe. Credit: Marek Jantač

The fossil skull of a woman in the Czech Republic provided the oldest modern human genome ever reconstructed, representing a population that was formed before the separation of the ancestors of today’s Europeans and Asians.

In an article published in Ecology and evolution of nature, an international team of researchers is analyzing the genome of an almost complete skull that was first discovered in Zlatý Kůň in the Czech Republic in the early 1950s and is now stored in the National Museum in Prague. Neanderthal segments DNA in their genome they were longer than the Ust’-Ishim individuals from Siberia, the previous oldest modern human series, suggesting that modern humans lived in the heart of Europe more than 45,000 years ago.

Zlatý Kůň Human skull

Side view of the mostly complete skull of Zlatý Kůň. Credit: Martin Frouz

The ancient DNA of Neanderthals and early modern humans recently showed that groups probably crossed paths somewhere in the Middle East after modern humans left Africa some 50,000 years ago. As a result, all people outside Africa carry about 2% to 3% of Neanderthal DNA. In modern human genomes, these Neanderthal segments of DNA have become shorter over time and their length can be used to estimate when an individual lived. Archaeological data released last year further suggests that modern humans were already present in Southeast Europe 47-43,000 years ago, but due to a lack of fairly complete human fossils and a lack of genomic DNA, there is little understanding of who these early human colonists were – or their relationship to ancient and modern human groups.

In a new study published in Ecology and evolution of nature, an international team of researchers reports that it is probably the oldest reconstructed modern human genome to date. First discovered in the Czech Republic, a woman known to researchers as Zlatý kůň (Golden Horse in Czech) showed longer pieces of Neanderthal DNA from the 45,000-year-old Ust’-Ishim of Siberia, the oldest modern human genome to date. The analysis suggests that it was part of a population that formed before the separation of the populations created by today’s Europeans and Asians.

Recent anthropological research based on the shape of the Zlatý kůň skull has shown similarities with people who lived in Europe before the Last Glacial Maximum – at least 30,000 years ago – but radiocarbon dating has yielded sporadic results, some even 15,000 years ago. It was only when Jaroslav Brůžek from the Faculty of Science in Prague and Petr Velemínský from the Prague National Museum collaborated with the genetic laboratories of the Max Planck Institute for the Study of Human History that a clearer picture emerged.

Zlatý Kůň Skull

The first attempts to have fun with Zlatý Kůň based on the shape of her skull suggested that she was at least 30,000 years old. Researchers now believe she lived more than 45,000 years ago. Credit: Martin Frouz

“We found evidence of cow DNA contamination in the analyzed bone, suggesting that the bovine-based glue used to strengthen the skull returned radiocarbon dates younger than the actual age of the fossil,” says Cosimo Posth, co-author of the study. Posth was previously the leader of a research group at the Max Planck Institute for the Science of Human History, and is currently a professor of archaeo- and paleogenetics at the University of Tübingen.

However, it is the Neanderthal DNA that led the team to their main conclusions about the age of the fossils. Zlatý kůň carried approximately the same amount of Neanderthal DNA in its genome as Ust Ishim or other modern humans outside Africa, but the segments of Neanderthal origin were on average much longer.

“The results of our DNA analysis show that Zlatý kůň lived closer to the time regarding Neanderthal admixture,” says Kay Prüfer, co-leader of the study.

Scientists have been able to estimate that Zlatý kůň lived approximately 2000 years after the last admixture. Based on these findings, the team claims that Zlatý kůň represents the oldest human genome to date, about the same age as – if not several hundred years older – Ust’-Ishima.

“It’s pretty intriguing that the earliest modern people in Europe failed in the end!” Just like Ust’-Ishim and Europe’s oldest skull from Oasis 1, Zlatý kůň shows no genetic continuity with modern humans who lived in Europe 40,000 years ago, “said Johannes Krause, senior author of the study and director of the Institute for Evolution. anthropology Max Planck.

One possible explanation for the discontinuity is a volcanic eruption of Campanian ignimbrite about 39,000 years ago, which severely affected the climate in the northern hemisphere and may have reduced the chances of Neanderthals and early modern humans surviving in large parts of Ice Age.

Skull sampling Zlatý Kůň

Micro-sampling of Zlatý Kůň stones from the base of the skull in a clean room at the Max Planck Institute for the Study of Human History, Jena. Credits: Cosimo Posth

As the progress of ancient DNA reveals more about the story of our species, future genetic studies of other early European individuals will help reconstruct the history and decline of the first modern humans to spread from Africa to Eurasia before the formation of modern-day non-African populations.

Reference: “Genome sequence of a modern human skull over 45,000 years old from Zlatý kůň in the Czech Republic”, by Kay Prüfer, Cosimo Posth, He Yu, Alexander Stoessel, Maria A. Spyrou, Thibaut Deviese, Marco Mattonai, Erika Ribechini, Thomas Higham , Petr Velemínský, Jaroslav Brůžek and Johannes Krause, 7 April 2021, Ecology and evolution of nature.
DOI: 10.1038 / s41559-021-01443-x