May 15, 2021

The mysterious substitution of all men of the Iberian Peninsula | Science

The mysterious substitution of all men of the Iberian Peninsula | Science

If it is difficult to understand a relationship when the two people are alive, to understand it when they both died 3,800 years ago seems like a fantasy, but it is not at all. The archeologist Luis Benítez de Lugo remembers the day of 2004 in which, in the middle of a sea of ​​manchego olive trees, an unusual tomb appeared, shared by a woman and a man of the Bronze Age. "It was spectacular," he recalls. In that intact grave from prehistory they were, accompanying the couple, their everyday objects. Next to him, a ceramic bowl, a dagger and an archer's bracelet. Next to her, another bowl, a small knife and some ivory buttons. Love, if there was one, does not fossilize.

A new DNA analysis has just given a monumental surprise about the identity of those two people, unearthed in the site of Castillejo del Bonete, just outside the town of Terrinches, in Ciudad Real. She was a local woman, but he was a man with Yamnaya ancestry, the nomads who left the steppes of present-day Russia about 5,000 years ago. The mixture, apparently, was repeated throughout the Iberian Peninsula. "There is an arrival of people from the steppes over several generations and they end up replacing local males. Now we must discuss whether they were put to the knife or if it was something more friendly, "says Benítez de Lugo, from the Autonomous University of Madrid.

A team of more than a hundred scientists published today in the magazine Science the genetic analysis of more than 400 people died in the Iberian Peninsula in ancient times of the last 8,000 years. The data, explains the geneticist Carles Lalueza Fox, suggest that the arrival of groups with ancestors of the steppes for 4,500 years meant "the replacement of 40% of the local population and almost 100% of men" of the peninsula. The process lasted about five centuries.

The Spanish geneticist Iñigo Olalde, from Harvard University.
The Spanish geneticist Iñigo Olalde, from Harvard University.

"The way in which this replacement occurred is subject to some controversy, especially among archaeologists," acknowledges Lalueza Fox, co-director of the study and CSIC researcher at the Institute of Evolutionary Biology, in Barcelona. "It is not a sudden invasion, but rather a colonization. A process similar to the colonization of America by Europeans, "he says.

On September 22, one of the main authors of the study, the American geneticist David Reich, already advanced part of its results in an event organized by the magazine New Scientist. "The collision of these two populations was not friendly, but men arrived from abroad displaced local men almost completely," he said then, before deciding to remain silent until the publication of his work.

"It is not a sudden invasion, but rather a colonization," says geneticist Carles Lalueza Fox

"I think it would be a mistake to jump to the conclusion that Iberian men were killed or forcibly displaced," he explains to EL PAÍS. "An alternative possibility is that local Iberian women prefer newcomers from central Europe in a context of strong social stratification," says Reich, of Harvard University.

"That they killed all men is quite unlikely, because there is no evidence of widespread violence in the archaeological record. But, in 500 years, all the paternal lineages disappear and only one remains. If there was no violence, there could be a social stratification so strong that the foreign clans reproduced much more. They could have a much higher status, because they had more resources ", hypothesizes the Spanish geneticist Iñigo Olalde, from the Reich team at Harvard.

Aida Andrades, expert in ancient pathogens of the Max Planck Institute in Jena (Germany), applauds the new work, in which she has not participated. In his opinion, the process of drastic change observed by the geneticists could be "complex and multifactorial". "We should consider the possibility that one or multiple diseases affect the population of the Iberian Peninsula in different ways and the population with steppe descent," he argues.

Remains of a North African man buried near present day Madrid about 4,000 years ago.
Remains of a North African man buried near present day Madrid about 4,000 years ago.

A year ago, the Andrades team found the bacteria responsible for the bubonic plague in the remains of two people who died 3,800 years ago in the steppes of present-day Russia. "I do not think the plague affects one sex more than the other, but perhaps the behavior of men is different from that of women, putting them at risk more often, for example having more contact with infected animals," says the researcher For Lalueza Fox, the next step is clear: "We have to look at the archaeological record with different eyes".

The new genetic analysis has brought other extraordinary surprises. In 1999, the works to build an industrial estate in the Madrid municipality of San Fernando de Henares uncovered a unique site from the Copper Age and the Bronze Age. There, according to the new DNA analysis, a North African man who died about 4,000 years ago was buried next to people of local origin. "It is surprising that an individual from North Africa reaches the center of the Peninsula. With what objective? ", He asks Corina Liesau, prehistorian of the Autonomous University of Madrid and researcher of the site, called Camino de las Yeseras. "What we know today is that this deposit, which received full between its local population to this migrant, is key to understanding the socioeconomic dynamics and surely religious"From that time, adds Liesau.

The prehistorian calls for caution when interpreting the genetic data that suggest a total replacement of the male population of the Iberian Peninsula throughout the Bronze Age. "We must continue to investigate this issue, specifying the time and how many generations it took," he warns. "The social relations in prehistory could be very different from the current ones, so we have to be very cautious and rigorous," he warns.

Last October 5, Liesau and another hundred archaeologists they wrote to this newspaper to criticize the use of the term "invasion", for being "totally out of context" in the rudimentary societies of the Bronze Age. Today, the CSIC has issued a statement assuring that the investigations of its scientists "show an invasion of descendants of steppe populations that replaced almost all men 4,000 years ago".


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