Men in Spain were almost totally wiped out and replaced by a mass movement of people from the Russian steppe, genetic analysis has revealed.
Transformation of the Iberian peninsula, which includes modern day Portugal and Spain, happened between 4,000 and 4,500 years ago during the Bronze Age.
Experts made the finding by studying the unique Y chromosome of males in the region, taken from fossils dating back over the past 8,000 years.
The same shift was not observed for women whose DNA remained relatively ‘local’ , with scientists unclear exactly why such dramatic change was ‘male specific’.
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Men in Spain were almost totally wiped out and replaced by a mass movement of people from the Russian steppe, genetic analysis has revealed. Pictured is one of the sites where excavation work took place at Balma Guilanyà on the Iberian peninsula
Researchers from the University of Hudersfield sequenced the genome of 403 Iberians who lived between 6,000 BC and AD 1,600.
The study shows in detail how Iberia’s population has changed drastically over time, from its hunter-gatherer origins before the arrival of farming 7,500 years ago, through to the medieval period and modern times.
Most striking was an influx of new people during the later Copper Age, otherwise known as the Beaker period because of the ubiquitous presence in burials of large drinking vessels, from about 4,500 years ago.
By the Early Bronze Age, 500 years later, these newcomers represented about 40% of Iberia’s genetic pool – but virtually 100% of their male lineages.
This suggests that the newcomers were mainly men, and that – somehow – they all but replaced the men living there previously, whilst the local women survived the takeover.
Tracing the Y chromosome let scientists trace the male line from father to son, as this genetic material is not present in women
The researchers said: ‘We reveal sporadic contacts between Iberia and North Africa by 2500 BC and, by 2000 BC, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry.’
Some of the finds the archaeologists found in the Iberian peninsula. Mesolithic hunter-gatherers found to be brothers. The same shift in genetic material was not observed for women, who remained relatively ‘local’
WHAT WAS THE BELL BEAKER CULTURE?
Between 4,700 and 4,400 years ago, a new bell-shaped pottery style spread across western and central Europe, and this period is called the ‘Bell Beaker’.
The period received its name due to the pottery’s distinctive bell-shaped beakers, decorated in horizontal zones by finely toothed stamps.
The decorated pots are almost ubiquitous across Europe, and could have been used as drinking vessels or ceremonious urns.
Believed to be originally from Spain, the Beaker folk soon spread into central and western Europe in their search for metals.
But the sheer variety of beaker artifacts across Europe has made the pottery difficult to define as coming from one distinctive culture.
A new study published in Nature suggests that the Beaker culture spread through Europe via two different mechanisms – the spread of ideas and migration.
Beaker-complex grave goods from La Sima III barrow, Soria, Spain. The set includes Beaker pots of the so-called ‘Maritime style’
What is even more striking now is that both Iberia and India had a similar source – a population of early metal-using stock breeders, who lived to the north of the Black Sea on Russian steppe lands, 5,000 years ago.
They fanned out in both directions, west across Europe and east into Asia, their based economy, domesticated horses and wheeled wagons giving them a crucial advantage over the indigenous farming populations.
Moreover, they are also thought to have brought the Indo-European languages spoken across Europe and India today.
Around 2,500 BC, the researchers found, Iberians began living alongside newcomers from central Europe who carried recent ancestry from those people on the Russian steppe.
Within a few hundred years, the two groups had extensively interbred.
One alternative possibility is that local Iberian women preferred the central European newcomers in a context of ‘strong social stratification,’ said Dr Lalueza-Fox
Transformation of the Iberian peninsula, which includes modern day Portugal and Spain, happened between 4,000 and 4,500 years ago during the Bronze Age. Pictured is another archeological burial site at Cueva de Chaves
This was beautifully exemplified at a Bronze Age site known as the Castillejo de Bonete in Spain, where a woman and man were found buried side by side.
Analyses revealed that the woman’s ancestry was entirely local, while the man had very recent ancestors from central Europe.
‘This is one of the strongest pieces of evidence in ancient-DNA research of sex bias in the prehistoric period,’ said Iñigo Olalde, a postdoctoral fellow in the lab of David Reich at Harvard Medical School and first author of the study.
Marina Silva added: ‘It’s an intriguing situation, because the Beaker culture originated in Portugal and spread across Europe from there – but at the same time, or shortly after, men who probably spoke Indo-European languages were moving in the opposite direction
‘Resolving the population dynamics in western Europe during the Copper and Bronze Ages is a big step towards understanding the origins of the Celtic languages, which were spoken across western Europe before the rise of the Roman Empire.’
WHAT DO WE KNOW ABOUT OUR ANCESTORS?
Four major studies in recent times have changed the way we view our ancestral history.
The Simons Genome Diversity Project study
After analysing DNA from 142 populations around the world, the researchers conclude that all modern humans living today can trace their ancestry back to a single group that emerged in Africa 200,000 years ago.
They also found that all non-Africans appear to be descended from a single group that split from the ancestors of African hunter gatherers around 130,000 years ago.
The study also shows how humans appear to have formed isolated groups within Africa with populations on the continent separating from each other.
The KhoeSan in south Africa for example separated from the Yoruba in Nigeria around 87,000 years ago while the Mbuti split from the Yoruba 56,000 years ago.
The Estonian Biocentre Human Genome Diversity Panel study
This examined 483 genomes from 148 populations around the world to examine the expansion of Homo sapiens out of Africa.
They found that indigenous populations in modern Papua New Guinea owe two percent of their genomes to a now extinct group of Homo sapiens.
This suggests there was a distinct wave of human migration out of Africa around 120,000 years ago.
The Aboriginal Australian study
Using genomes from 83 Aboriginal Australians and 25 Papuans from New Guinea, this study examined the genetic origins of these early Pacific populations.
These groups are thought to have descended from some of the first humans to have left Africa and has raised questions about whether their ancestors were from an earlier wave of migration than the rest of Eurasia.
The new study found that the ancestors of modern Aboriginal Australians and Papuans split from Europeans and Asians around 58,000 years ago following a single migration out of Africa.
These two populations themselves later diverged around 37,000 years ago, long before the physical separation of Australia and New Guinea some 10,000 years ago.
The Climate Modelling study
Researchers from the University of Hawaii at Mānoa used one of the first integrated climate-human migration computer models to re-create the spread of Homo sapiens over the past 125,000 years.
The model simulates ice-ages, abrupt climate change and captures the arrival times of Homo sapiens in the Eastern Mediterranean, Arabian Peninsula, Southern China, and Australia in close agreement with paleoclimate reconstructions and fossil and archaeological evidence.
The found that it appears modern humans first left Africa 100,000 years ago in a series of slow-paced migration waves.
They estimate that Homo sapiens first arrived in southern Europe around 80,000-90,000 years ago, far earlier than previously believed.
The results challenge traditional models that suggest there was a single exodus out of Africa around 60,000 years ago.