Study links ancestors of Iberian farmers to modern-day Basques

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This is an illustration of every day life in the El Portalon cave during the Neolithic and Copper Age. Credit: Artist: María de la Fuente

A new genomic study has unraveled the secrets of modern-day Basques suggesting that there is a link between early Iberian farmers and Basques.

Researchers extracted and analysed the genomes from eight Iberian stone-age farmer remains discovered from El Portalón and suggested that early Iberian farmers are the closest ancestors to modern-day Basques thereby debunking a previously held notion that linked Basques to earlier pre-farming groups.

Researchers at the Uppsala University revealed that farming was a gift to Iberia by the same group who is known to have introduced farming in northern and central Europe. Not only farming, researchers also found that these people admixed with local, Iberian hunter-gather groups, a process they say continued for at least 2 millennia.

There have been almost no studies that have looked into the part of Iberia because almost all previous studies concentrated on what went about in northern and central Europe. This wide gap in the understanding of Iberian’s past has finally been filled.

For their study, scientists investigated eight individuals associated with archaeological remains from farming cultures in the El Portalón cave from the well-known Anthropological site Atapuerca in northern Spain. They extracted the DNA from the remains of individuals who are believe to have lived 3,500-5,500 years ago and generated the first genome-wide sequence data from Iberian ancient farmers and observed that these share a similar story to those of central and northern Europe.

 The burial was found deliberately sheltered by large limestone blocks and three other blocks carefully protected the child´s head. The grave was scattered with grave goods suggesting a special status of this boy. The burial is covered by different ornaments, such as ceramics fragments of different sizes sealed with a green-like clay, vessel parts, flint flakes, a bone arrowhead, quartzite and, most surprisingly, the boy was left accompanied by an almost complete calf in anatomical position. This child possibly died of malnutrition as evidenced by a series of lesions in his skull and bones indicating the boy suffered from rickets and/or scurvy (Castilla et al, 2014) at different stages of his life. Credit: Eneko Iriarte

The burial was found deliberately sheltered by large limestone blocks and three other blocks carefully protected the child´s head. The grave was scattered with grave goods suggesting a special status of this boy. The burial is covered by different ornaments, such as ceramics fragments of different sizes sealed with a green-like clay, vessel parts, flint flakes, a bone arrowhead, quartzite and, most surprisingly, the boy was left accompanied by an almost complete calf in anatomical position. This child possibly died of malnutrition as evidenced by a series of lesions in his skull and bones indicating the boy suffered from rickets and/or scurvy (Castilla et al, 2014) at different stages of his life. Credit: Eneko Iriarte
This means that they originate from a southern wave of expansion, and also admixed with local hunter-gatherer populations and spread agricultural practices through population expansions. The authors noticed that although they share these similarities with other European farmers, this early Iberian population has its own particularities.

“We show that the hunter-gatherer genetic component increases with time during several millennia, which means that later farmers were genetically more similar to hunter-gatherers than their forefathers who brought farming to Europe,” says Dr. Torsten Günther of Uppsala University and one of the lead authors.

The study further shows that in comparison to all modern Spanish populations, the El Portalón individuals are genetically most similar to modern-day Basques. Basques have so far – based on their distinct culture, non-indo-European language, but also genetic make-up – been thought of as a population with a long continuity in the area, probably since more than 10,000 years ago.

“The difference between Basques and other Iberian groups is these latter ones show distinct features of admixture from the east and from north Africa.” says Prof. Mattias Jakobsson of Uppsala University, who headed the study.

These findings shed light into the demographic processes taking place in Europe and Iberia during the last 5,000 years which highlights the unique opportunities gained from the collaborative work of archaeologists, anthropologists and geneticists in the analysis of ancient DNA.

The study is published in journal Proceedings of the National Academy of Sciences of the USA, PNAS.