A new study analysing the genomes of a few dozens of individuals from the ice age has identified the early ancestors of present-day Europeans. A 35 000 year old humerus from the Goyet caves in Belgium belongs to the earliest ancestors of Europeans. The genetic information also shows that people from the Near East mixed with Europeans (starting) 14 000 years ago. Moreover, the amount of Neanderthal DNA in modern human genomes decreased over the millennia.
About 45 000 years ago, during the last ice age, modern humans populated the area we now call Europe. Despite low temperatures and glaciers covering a large part of the continent between 25 000 and 19 000 years ago, they never left the area.
The archaeological evidence from these hunter-gatherers, such as bones, tools, cave paintings and other artefacts, can only hint at how members of different populations were related to one another and to present-day Europeans. Analysing genomic data can give a detailed image of these genetic relationships. An international research team analysed the nuclear DNA of 51 humans who lived between 45 000 and 7000 years ago. It is the largest genetic reconstruction of modern humans in Europe before the start of agriculture about 8 500 years ago. Paleoanthropologist Patrick Semal of the Royal Belgian Institute of Natural Sciences (RBINS) cooperated in this study.
Belgian European ancestors
The analyses demonstrate that the branch of the first group of modern humans, coming from Africa to populate Europe 45 000 years ago, died out. Their genetic material is not present in the current European gene pool. However, starting 37 000 years ago, all analysed humans did contribute to the genetic composition of present-day Europeans. The humerus from the Belgian Goyet caves, belonging to the collections of the RBINS, is the oldest trace of these early European ancestors. The 35 000-year-old bone belongs to a man.
Archeological traces reveal this group belonged to the Aurignacian culture (remember the Venus of Hohle Fels). Later, between 34 000 and 26 000 years ago, the group was replaced by a population belonging to the Gravettian culture (remember the Venus of Willendorf). But the Goyet group did not disappear: starting about 25 000 years ago, descendants appear in the north of Spain, where they survived during the Latest Glacial Maximum, when glaciers reached southern Europe. When temperatures increased, 19 000 years ago, the Goyet descendants, who belonged to the Magdalenian culture (remember Lascaux), spread over Europe.
Migrations from the East
The study, published in Nature this week, found that (starting) 14 000 years ago, a genetic component became widespread in a large part of Europe. This component is present in the DNA of present-day Near Easterners. The researchers assume that large groups from the Near East migrated to Europe when the climate became warmer and glaciers melted. Some fossils even show traces of East Asian DNA, pointing to a migration from the Far East.
Neanderthal DNA disappears
Whereas present-day people of non-African descent carry about 2 percent Neanderthal DNA, the earliest samples in the study contained between 3 and 6 percent. The researchers believe this DNA, probably containing many bad mutations, was forced out by natural selection. It is remarkable that it takes tens of thousands of years before the genetic material of our ‘cousins’, with whom we lived and mixed for some thousands of years, disappears from our population.
The study analysed five fossils from the Goyet caves; three humeri and two tibias, covering a period of 35 000 to 15 000 years ago. The fragments of human bone were found in the 1860s by geologist Edouard Dupont. Only recently they turned up, when the collection of the RBINS was re-examined. The fossils were also recently examined in a study focusing on mitochondrial DNA (only reflecting the descent through the female line).