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news focus Iberia’s Iberia’s ancient inhabitants Tracing the genetic history of Spain and Portugal Detailed DNA studies have the potential to shed light on how present populations were formed over thousands of years. We take a look at research offering fresh insights into the prehistory of the Iberian Peninsula and consider what genes can tell us about the coming of new ages. Today, the weather in Spain and Portugal is an attractive feature that draws visitors to their sandy beaches and splendid cities, but the climate in this south-west corner of Europe also made an important contribution to the distinct population history of the region. Like Italy, the Iberian Peninsula remained warm during the last Ice Age, offering a potential refuge for plants, animals, and people, who would not have survived in the low temperatures elsewhere in Europe. New research by large international teams of geneticists and archaeologists has revealed details of this population history, shedding light on intriguing changes that took place during prehistory. One study, led by researchers at the Max Planck Institute for the Science of Human History and recently published in Current Biology, analysed the genomes of ten new individuals from Late Upper Palaeolithic, Mesolithic, and Neolithic sites in Iberia. Previous investigations had indicated that after the end of the last Ice Age, hunter-gatherers with ancestry related to a 14,000-year-old individual from Villabruna, Italy, dominated western and central Europe, largely replacing earlier genetic ancestry related to 19,000- to 15,000-year-old individuals associated with the Magdalenian culture. Intriguingly, though, in Iberia both lineages were present in all the hunter-gatherers studied, dating back some 18,700 years to the oldest individual, who was found in El Mirón cave in Cantabria. This dual Palaeolithic ancestry supports the idea that the Peninsula acted as a refuge for people during the Ice Age and points to an early connection between Iberia and another such refuge in Italy. The dual ancestry was also found in the genomes of newly analysed Early and Middle Neolithic individuals, offering some clues as to what happened when early farmers from western Anatolia rapidly expanded westward to the Iberian Peninsula some 7,600 years ago. Vanessa Villalba-Mouco of the Max Planck Institute for the Science of Human History, one of the authors of the study in Current Biology and also of the study published in Science (see below), explains: ‘The transition from foraging to farming correlates well with the genomic landscape in prehistoric Europe. Generally, what we see during this transition is a turnover in the genomic make-up of the individuals. The expanding first farmers brought with them a completely new type of genetic ancestry that is related to the Near Eastern population. Neolithic individuals from Iberia also carry this ancestry as the biggest component, but still retain a small proportion of hunter-gatherer ancestry that was picked up by admixture with local hunter-gatherer groups.’ ‘The hunter-gatherer groups were also genetically diverse, but the last groups who encountered the first farmers were quite homogeneous and commonly named Western Hunter-Gatherers. In fact, our study has shown that the Iberian Peninsula retained i d a ) ( o p p S á n ch e z fu e nte s i s Lu J o s é – i ch E n r Lu go d e í te z B e n i s : Lu P H OTO 10 CurrentWorldArChAeology Issue 95
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: C E PA P UA B a higher hunter-gatherer diversity with at least two Paleolithic lineages leaving a genetic legacy.   The fact that we still see this dual hunter-gatherer ancestry mixed in as a small proportion in the Iberian early farmers tells us that this mix had happened locally between the last Iberian hunter-gatherers and incoming farmers.’ i f u e nte s Cí g u e z l Ro d r i g u e : M i P H OTO i n a rch Mi a : Lu c T E X T Steppe aside The results of a second study, published in Science, revealed the remarkable extent of transition later in prehistory when more newcomers arrived. A team led by researchers at Harvard Medical School and the Broad Institute analysed 271 new ancient Iberians from the Mesolithic, Neolithic, Copper Age, Bronze Age, Iron Age, and historical periods to build a detailed picture of Iberia’s genetic history over the past 8,000 years. They greatly expanded the dataset for Bronze Age Iberia from 7 individuals to 60, who lived in the region between around 2200 and 900 BC. During this period, ancestry from the Pontic-Caspian Steppe region in Russia and Ukraine appeared throughout Iberia, as lead author Iñigo Olalde from Harvard Medical School told CWA: ‘Our findings indicate that people with very recent ancestors from the steppe also had substantial impact in the south-western corner of Europe, although when they arrived into Iberia they were already admixed with local populations they encountered along the way in eastern and central Europe.’ But what was happening to the local males? ‘There are a number of different social processes that could be consistent with the genetic patterns we observe, the disappearance of local male lineages,’ Iñigo said. ‘Maybe the most simplistic photo Between about 2500 and 2000 BC, there was a replacement of 40% of Iberia’s ancestry by people with Steppe ancestry, and, strikingly, a nearly total turnover of the Y-chromosomes. Seemingly, predominantly male newcomers were somehow making local males vanish from the genetic record. This remarkable example of sex bias is illustrated by a Bronze Age tomb from Castillejo del Bonete, where a male with Steppe ancestry and a female with ancestry similar to Copper Age Iberians were found side by side. ft Two Late Upper Palaeolithic individuals from the rock shelter at Balma Guilanyà in north-eastern Iberia were studied. Like other Iberian hunter-gatherers, they carry two lineages, from both Villabruna- and Madgalenian-related individuals, suggesting that the Iberian Peninsula provided refuge for people during the Ice Age. belo w le ft At Castillejo del Bonete a male with Steppe ancestry was buried alongside a female with ancestry similar to Copper Age Iberians. This Bronze Age tomb illustrates the striking genetic turnover that took place between about 2500 and 2000 BC, when nearly all of Iberia’s Y-chromosomes were replaced by people with Steppe ancestry. belo w Analysis of this Copper Age male from Camino de las Yeseras (Madrid, Spain) revealed that he or all his recent ancestors were of North African origin. scenario is one where incoming males eliminated local males and mated with local women. However, other more complex scenarios are also possible, like one in which you have strong power inequalities between local and incoming clans, coupled with a very rigid patriarchal and patrilineal social structure in the foreign clans that over several centuries resulted in the loss of local male lineages.’ Genetic evidence paints only one part of the picture and more archaeological research is needed to work out what’s going on. In central and northern Europe, increases in Steppe ancestry are linked to the introduction of Indo-European languages, but, in Iron Age Iberia, Steppe ancestry also flowed into non-Indo-European language speaking areas, including the Basque Country, which retained its existing language. Euskara is today the only non-Indo-European language in Western Europe. After the arrival of Steppe populations, Basques became somewhat genetically isolated from the rest of Iberia and so they were less affected by later gene flows that had an impact on populations elsewhere in the peninsula. Thanks to its position on the Mediterranean, the Iberian Peninsula has a long history of interacting with other regions over the waters. North Africa is one such region, and there is genetic evidence of sporadic contacts between the two lands on either side of the Strait of Gibraltar during the Copper and Bronze Ages. For example, analysis of one Copper Age male from Camino de las Yeseras, radiocarbon dated to 2473-2030 BC, has found that he or all his recent ancestors were of North African origin. These contacts, also supported by the presence of African ivory at a number of Iberian sites, had little impact on the Copper and Bronze Age inhabitants. It was not until later – at least by the Roman period – that gene flow from North Africa began to leave its mark on the ancestry of Iberia, a contribution that continued into the period of Muslim rule in the peninsula between the 8th and 15th centuries AD. u p f r o n t n e w s f o c u s FURTHER READING Vanessa Villalba-Mouco et al (2019) ‘Survival of Late Pleistocene hunter-gatherer ancestry in the Iberian Peninsula’, Current Biology. https://doi.org/10.1016/j.cub.2019.02.006 Iñigo Olalde et al (2019) ‘The genomic history of the Iberian Peninsula over the past 8000 years’, Science. https://doi.org/10.1126/science.aav4040 www.world-archaeology.com CurrentWorldArchaeology 11

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news focus

Iberia’s Iberia’s ancient inhabitants

Tracing the genetic history of Spain and Portugal

Detailed DNA studies have the potential to shed light on how present populations were formed over thousands of years. We take a look at research offering fresh insights into the prehistory of the Iberian Peninsula and consider what genes can tell us about the coming of new ages.

Today, the weather in Spain and Portugal is an attractive feature that draws visitors to their sandy beaches and splendid cities, but the climate in this south-west corner of Europe also made an important contribution to the distinct population history of the region. Like Italy, the Iberian Peninsula remained warm during the last Ice Age, offering a potential refuge for plants, animals, and people, who would not have survived in the low temperatures elsewhere in Europe.

New research by large international teams of geneticists and archaeologists has revealed details of this population history, shedding light on intriguing changes that took place during prehistory. One study, led by researchers at the Max Planck Institute for the Science of Human History and recently published in Current Biology, analysed the genomes of ten new individuals from Late Upper Palaeolithic, Mesolithic, and Neolithic sites in Iberia.

Previous investigations had indicated that after the end of the last Ice Age, hunter-gatherers with ancestry related to a 14,000-year-old individual from Villabruna, Italy, dominated western and central Europe, largely replacing earlier genetic ancestry related to 19,000- to 15,000-year-old individuals associated with the Magdalenian culture. Intriguingly, though, in Iberia both lineages were present in all the hunter-gatherers studied, dating back some 18,700 years to the oldest individual, who was found in El Mirón cave in Cantabria. This dual Palaeolithic ancestry supports the idea that the Peninsula acted as a refuge for people during the Ice Age and points to an early connection between Iberia and another such refuge in Italy.

The dual ancestry was also found in the genomes of newly analysed Early and Middle Neolithic individuals, offering some clues as to what happened when early farmers from western Anatolia rapidly expanded westward to the Iberian Peninsula some 7,600 years ago. Vanessa Villalba-Mouco of the Max Planck

Institute for the Science of Human History, one of the authors of the study in Current Biology and also of the study published in Science (see below), explains:

‘The transition from foraging to farming correlates well with the genomic landscape in prehistoric Europe. Generally, what we see during this transition is a turnover in the genomic make-up of the individuals. The expanding first farmers brought with them a completely new type of genetic ancestry that is related to the Near Eastern population. Neolithic individuals from Iberia also carry this ancestry as the biggest component, but still retain a small proportion of hunter-gatherer ancestry that was picked up by admixture with local hunter-gatherer groups.’

‘The hunter-gatherer groups were also genetically diverse, but the last groups who encountered the first farmers were quite homogeneous and commonly named Western Hunter-Gatherers. In fact, our study has shown that the Iberian Peninsula retained i d a )

( o p p

S á n ch e z fu e nte s i s

Lu

J o s é

–

i ch

E n r

Lu go d e

í te z

B e n i s

: Lu

P H OTO

10

CurrentWorldArChAeology

Issue 95

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