The wandering men turned the DNA of Spain

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Burials of men and women of the Bronze Age — Legend

Burials at the Bronze Age: Iberia experienced a dramatic genetic change during this period

A study reveals that the massive migration of men transformed the genetic makeup of the Spaniards in the Bronze Age.

DNA evidence shows that migrants flocked to the Pyrenees, replacing existing male lineages in the region in the space of 400 years.

It is unclear whether there has been a violent invasion or whether a social structure centered on men has played an important role.

The result comes from the largest study of its kind.

The researchers reconstructed the history of Iberia's population (modern Spain and Portugal) over 8,000 years – the largest slice of time tackled by research on ancient DNA.

Their study is published in the journal Science.

They extracted and analyzed the DNA of 403 Iberians living between 6,000 years before Christ and 1,600 years after Christ.

Bronze Age migrants have some of their ancestry to the Neolithic (Stone Age) farmers found throughout Europe – including Spain – while the rest of their genetic heritage resembled that of people living at the time in the Russian steppe.

This steppe ancestry was introduced in Europe by nomadic pastoralists who migrated to western Asia and the eastern fringes of Europe.

Old Britons 'replaced' by newcomers

Crisis of stone age

One of the triggers could have been a crisis that caused a massive drop in population in Europe towards the end of the Neolithic (which preceded the Bronze Age). Recent studies suggest that the plague may have played a role.

When the steppes moved to the west, they recovered elements of the culture from people with whom they intermingled. In Central Europe, a mixed crop of this type, known as the Bell Beaker tradition, has been formed. The Beakers and their descendants may have established highly stratified (unequal) societies in Europe, including Iberia – where they begin to appear from 2500 BC.

Legend

A new tradition: bell-shaped pottery from the Bronze Age of Camino de las Yeseras near Madrid

The researchers examined the Y chromosome, a packet of DNA passed from father to son more or less unchanged. It can be used to track the inheritance of the male line. Around 2000 BC, the Y chromosome lines carried by Neolithic farmers had largely been eliminated from the Iberian gene pool, in favor of those of the newcomers.

When the team analyzed the DNA of the entire genome (the complete set of genetic material found in the cell nuclei), she discovered that the Iberians then traced 40% from their origins to the new population.

The newcomers – originally Bell Beaker – brought innovations such as bronze work (including making bronze weapons) and were probably mounted on horseback. These may have given them a military advantage over stone-age agricultural societies, but have probably also imparted a higher social status to new men.

Legacy Models

Co-author Iñigo Olalde of the Harvard Medical School in the United States said, "It would be a mistake to conclude that Iberian men have been killed or forcibly displaced." He added: "The archeological archives give no clear evidence of an explosion of violence at this time".

On the contrary, the high social status of newcomers may have been associated with greater success in procreation. "Their male descendants would have inherited wealth and social status, and their reproductive success would also be much higher," Dr. Olalde told BBC News.

A system emphasizing masculine power and inheritance could have been essential: "A patrilineal and possibly patriarchal social structure would further amplify the patterns observed, since only the eldest son would inherit clan properties, while other sons to try to establish their own clans and expand their Y lineages to new territories, "he said.

An even more extreme replacement pattern was observed at about the same time in Britain, where Bell Beakers replaced 90% of the ancestors that existed before their arrival.

Fortified settlements

"At least in the east and south-east, we are witnessing a change in settlement patterns (…) that lasts until the arrival of the Romans," said the co-ordinator. author, Dr. Carles Lalueza-Fox, of the University of Barcelona.

In this region, the Iberian culture of the Iron Age has established fortified settlements on the heights.

"The Iberians lived in settlements and constituted a violent society, structured in tribes, something clearly changed the social structure that existed at the end of the Neolithic."

Legend

The Dama de Elche was a product of the Iberian culture of the east coast of Spain

By examining human remains from an earlier period, the study found that people regaining a significant percentage of their ancestors among the earliest European settlers survived in southern Spain until the end of the war. to the spread of agriculture 6,000 years ago.

The team also studied genome data from Moorish Spain (AD 711-1492), when parts of the peninsula were under the control of Muslim emirs of North African descent .

Legend

The palace of the Alhambra in Granada, seat of the last Muslim emirate of Iberia

The North African influence was present in the Iberian Peninsula from the Roman period at least. But the researchers found a radical change in the genetic makeup of the inhabitants of the Moorish-controlled areas after the "Reconquista", when the Christian armies regained control of the peninsula. The conquerors expelled many Muslims, although some were allowed to remain as they converted to Christianity.

While many Moorish individuals analyzed in the study appear to have a 50:50 mix of North African and Iberian ancestry, North African ancestry on the peninsula averages only 5%.

Modern Iberians derive about 50% of their origins from Neolithic farmers, 25% from ancient hunter-gatherers and 20% from the steppes.

Faces of Iberia's past

Cut heads

Legend

The cut Iberian head was probably presented as a war trophy. A hole in the forehead marks where a huge nail was sunk

The inhabitants of the iron age Iberian civilization of the east coast of Spain have usually cremated their dead. The cremation process prevented scientists from extracting the DNA from these remains. While culture was responsible for great works of art, such as the sculpture of Dama de Elche, the Iberians also had a violent side. They drove large nails into the cut heads of enemies killed in action and displayed them in public spaces in the form of war trophies. About forty such heads were discovered in the Iberian colony of Ullastret, which allowed scientists to analyze their DNA.

African ancestors

The study revealed that two burials covered strong black African origins. The two individuals came from Granada, in southwestern Spain, where the last Muslim emirate resisted until its conquest by Christians in 1492. One of them is from a tenth century cemetery, where bodies were buried in the Islamic tradition. of Mecca. The other individual dates from the 16th century, after the Christian conquest of Granada. It is thought that they belong to the community of Morisco – former Muslim converts to Christianity (to be later expelled from Spain).

Germanic migrants

After the fall of the Roman Empire, wandering tribes from the north and east of Europe invaded the Iberian Peninsula. The Visigoths, who spoke a language close to Swedish, German and English, took control of the region. They founded the Spanish monarchy that continues today and introduces laws that were the basis of those used by later Christian kingdoms. The burials of Pla de l'Horta, in northeastern Spain, include a mother and a daughter of Visigothic origin. Their genomes suggest that they are of recent Eastern European descent, while the DNA of the cell's batteries, or mitochondria – transmitted more or less unchanged from mother as a child – is of a type associated with the populations of East Asia. This is a sign of the genetic complexity of the eastern steppe where their roots are found.

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