A mass migration of men changed the genome of people in Spain during the Bronze Age, as a study shows.
DNA evidence shows that migrants flocked over the Pyrenees and replaced existing male lineages within the region by 400 years.
It remains unclear whether there was a violent invasion or whether a male-centered social structure played an important role.
The result comes from the largest study of its kind.
Researchers reconstructed the population history of Iberia (modern Spain and Portugal) over 8,000 years ̵
Your study was published in the Science Journal.
They extracted and analyzed DNA from 403 Iberians, who died between 6,000 BC. Chr. And n. Chr. Lived 1,600.
The Bronze Age male migrants recorded some of their ancestry in Neolithic (Stone Age) peasants throughout Europe – including Spain – while the rest of their genealogy resembled that of the people living in the Russian steppe.
This steppe descent was introduced to Europe by nomad shepherds migrating west from Asia and the eastern edge of Europe.
Ancient Britons were replaced by newcomers.
Stone Age Crisis
One of the triggers It was a crisis that plummeted European populations toward the end of the Neolithic Age (which preceded the Bronze Age). Recent studies indicate that the plague may have played a role.
When the steppe people moved west, they brought in cultural elements from people they mingled with on the way. In Central Europe, such a mixed culture formed, which is known as the Bell Beaker tradition. The beakers and their descendants may have established strongly stratified (dissimilar) societies in Europe, including Iberia, where they date from 2.500 BC. BCE emerged.
The researchers studied the Y chromosome – a DNA packet more or less unchanged inherited from father to son. It can be used to track the inheritance of male leads. Around 2,000 BC Y chromosome lines, carried by Neolithic farmers, were largely eliminated from the Iberian gene pool in favor of the newcomers.
When the team analyzed DNA from the entire genome – all the genetic material found in the cell nuclei – they found that later Iberians traced 40% of their ancestors back to the new population.
The newcomers – from Bell Beaker – brought innovations such as bronze processing (including the manufacture of bronze weapons) and were probably riding horses. These may have given them a military advantage over Stone Age peasant societies, but they have probably also given the incoming men a higher social status.
Co-author Iñigo Olalde of Harvard Medical School, USA, said: "It would be a mistake to conclude that Iberian males were killed or expelled." He added, "The archaeological reports give no clear evidence of an outbreak of violence during this period. "
Instead, the high social status of newcomers may be associated with greater reproductive success. "Her male offspring had inherited wealth and social status, and they also had a much higher reproductive success," Dr. Olalde to BBC News.
A system that emphasized male power and heredity might have been the key: "The patriarchal social structure would further reinforce the patterns observed, as only the first-born son might inherit the clan's property while the other sons move out and try would build their own clans, spreading their Y lineage over new territories, "said.
An even more extreme pattern of replacement occurred in Britain at the same time as Bell Beakers replaced 90% of the ancestors living there.
"At least in the East and Southeast we see a change in settlement patterns that persists until the arrival of the Romans," said co-author dr. Carles Lalueza-Fox from the University of Barcelona.
In t In his region, the Iberian culture of the Iron Age, they built high-altitude settlements.
"The Iberians lived in hilltop settlements and were a violent society structured according to tribal structures, something that clearly changes the social structure that existed in the late Neolithic period."
Looking at human remnants from an earlier period, the study found that humans, who attribute most of their ancestors to some of Europe's first settlers, survived in southern Spain until the spread of agriculture six thousand years ago.
The team also studied genomic data from Moorish Spain (711-1492 AD), as parts of the peninsula were under the control of Muslim Emirirs of North African origin.
There was a North African influence in Iberia, at least in Roman times. However, the researchers found a dramatic shift in the genetic makeup of people from Moorish-controlled regions after the "Reconquista", as Christian armies took control of the peninsula. The conquerors expelled many Muslims, although some were allowed to stay if they converted to Christianity.
While many Moorish individuals analyzed in the study seem to be a mix of North African and Iberian descent, today the peninsula is only 5%.
About 50% of the modern Iberians are from Neolithic peasants, 25% from former hunters and 20% from the steppe peoples.
Faces of Iberia's Past
People of the Iberian civilization of the Iron Age on the Spanish east coast generally burned their dead. The burning process prevented scientists from extracting DNA from these residues. While the culture was responsible for large works of art such as the sculpture Dama de Elche, the Iberians also had a violent side. They hammered with large nails through the severed heads of enemies killed in battle and exposed them as war trophies in public space. In the Iberian settlement of Ullastret, around 40 such heads have been found that allow scientists to analyze their DNA.
Two burials in the study revealed a high level of Black African ancestry. Both were from Granada in southwestern Spain, where the last Muslim Emirate survived until its conquest by Christians in 1492. One of the relatives came from a 10th-century cemetery where bodies were buried by Mecca in Islamic tradition. The other person is from the 16th century, after the Christian conquest of Granada. It is believed that they are from the Morisco community – former Muslims converted to Christianity (only to be later expelled from Spain).
After the decline of the Roman Empire, they migrated tribes from northern and eastern Europe to Iberia. The Visigoths, who spoke Swedish, German and English, took control of the region. They founded the Spanish monarchy, which continues to this day, and introduced laws that formed the basis for those who later used Christian kingdoms. The funerals at Pla de l & # 39; Horta in northeastern Spain include a mother and a daughter of Visigoth origin. Their genomes suggest that they were recently from Eastern Europe, while DNA from cell batteries or mitochondria – which are more or less passed on from mother to child – is of a type associated with East Asian populations. It is a sign of the genetic complexity of the eastern steppe region in which its roots lie.
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