Europeans most probably descended from hunter-gatherers

Modern Europeans and the European farmers of the Neolithic period share only very few genetic similarities

11.11.2005

It seems that the ancestors of modern Europeans were not the first farmers who lived in Europe approximately 7,500 years ago, as had generally been assumed. After analyzing genetic material of these early European farmers, researchers at Johannes Gutenberg University Mainz (JGU) and colleagues from the UK have concluded that modern Europeans have next to no genetic relationship with these Neolithic farmers. "Our data actually suggest that we Europeans are descended from Paleolithic hunter-gatherers," states Junior Professor Dr. Joachim Burger of the JGU Institute of Anthropology. The results obtained by his work group were recently published in the specialist journal "Science".

Agriculture and animal husbandry appeared about 12,000 years ago in the Fertile Crescent, a region in the northern Arabian Peninsula, and then spread to Europe by way of Anatolia. Archaeologists, anthropologists, and geneticists have puzzled for decades about whether modern Europeans are descended from these farmers or from the hunter-gatherers who, at the time that the farmers migrated here, had already been established in Europe for a much longer period of time, i.e., about 40,000 years.

It has been assumed to date that not only other cultural aspects were spread together with agriculture and animal husbandry, but also genetic material and language. The appearance of the linear pottery culture marks the advent of agriculture and animal husbandry in central Europe about 7,500 years ago. Having originated in Hungary and Slovakia, this was one of the oldest farming cultures of the Neolithic period and it spread to the Paris Basin and Ukraine over the span of about 500 years. The rapid spread of linear pottery itself, the name coming from the bands of linear decoration that appear on storage vessels of the time, and the fact that there is so little difference between finds at archaeological sites spread over a huge area of almost one million square kilometers indicate that this dissemination was mainly the result of migration. On the other hand, some archaeological studies suggest that local hunters and gatherers switched to agriculture without genetically mixing with these early farmers to any significant extent. Genetic studies of modern Europeans have produced contradictory results: Estimates of the proportion of the genetic make-up of the current population that can be attributed to Neolithic farmers range from 20% to 100%. "But as far as we are aware, a truly conclusive study of the DNA of ancient skeletons had yet to be published," says Burger.

The work undertaken by Burger and his colleagues, which was funded by the German Federal Ministry of Education and Research, represents the first attempt to reconstruct by means of DNA analysis the events surrounding the introduction of agriculture in the early Neolithic period. To solve the riddle of the origin of modern Europeans, the researchers collected 57 human skeletons from 16 linear pottery culture sites in Germany, Austria, and Hungary. The sites included the well-known archaeological settlements in Flomborn, Schwetzingen, Eilslebel, Asparn-Schletz, but also new excavation sites, such as Halberstadt. DNA was extracted from both bones and teeth. In the case of 24 individuals, the DNA was in sufficiently good condition to be analyzed. The analyses were taken on mitochondrial DNA, which is passed exclusively through the maternal line. This makes it possible to trace genetic descent in an unbroken line through the ages.

To their astonishment, Burger and his colleague, Wolfgang Haak, discovered a form of DNA in the samples that is very rarely present in modern Europeans. This characteristic and rare N1a haplogroup was present in six of the 24 individuals. "In the global database of 35,000 modern DNA sequences, fewer than 50 Europeans have this ancient farmer DNA type today," explains geneticist Dr. Peter Forster of Cambridge University. Computer simulations performed by his colleague, Dr. Shuichi Matsumura, showed that these early farmers could only have had a limited impact on our current gene pool. "It thus seems more likely to us now that our ancestors were probably hunters and gatherers," is the conclusion that Burger and Haak draw on the basis of their results. In their next research project, they plan to find out who our ancestors actually were and what happened to the early farmers.