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    Iberian Ancient DNA on the works

    So the ISBA 2018 has blessed us with great new prospective studies for those of us with an interest in Iberian genetics.

    The genetic history of the Iberian Peninsula over the last 8000 years

    I. Olalde1, N. Rohland1, S. Mallick1,2,3, N. Patterson2, M. Allentoft4, K. Kristiansen5, K. G. Sjögren5, R. Pinhasi6, C. Lalueza-Fox7D. Reich1,2,3

    The Iberian Peninsula, lying on the southwestern corner of Europe, provides an excellent opportunity to assess the final impact of population movements entering the continent from the east and to study prehistoric and historic connections with North Africa. Previous studies have addressed the population history of Iberia using ancient genomes, but the final steps leading to the formation of the modern Iberian gene pool during the last 4000 years remain largely unexplored. Here we report genome-wide data from 153 ancient individuals from Iberia, more than doubling the number of available genomes from this region and providing the most comprehensive genetic transect of any region in the world during the last 8000 years. We find that Mesolithic hunter-gatherers dated to the last centuries before the arrival of farmers showed an increased genetic affinity to central European hunter-gatherers, as compared to earlier individuals. During the third millennium BCE, Iberia received newcomers from south and north. The presence of one individual with a North African origin in central Iberia demonstrates early sporadic contacts across the strait of Gibraltar. Beginning ~2500 BCE, the arrival of individuals with steppe-related ancestry had a rapid and widespread genetic impact, with Bronze Age populations deriving ~40% of their autosomal ancestry and 100% of their Y-chromosomes from these migrants. During the later Iron Age, the first genome-wide data from ancient non-Indo-European speakers showed that they were similar to contemporaneous Indo-European speakers and derived most of their ancestry from the earlier Bronze Age substratum.With the exception of Basques, who remain broadly similar to Iron Age populations, during the last 2500 years Iberian populations were affected by additional gene-flow from the Central/Eastern Mediterranean region, probably associated to the Roman conquest, and from North Africa during the Moorish conquest but also in earlier periods, probably related to the Phoenician-Punic colonization of Southern Iberia.
    So it seems there was a population structure in the Iberian peninsula as it pertains to the Hunter Gatherer populations, this other abstract appears to support that notion.

    The Neolithic transition in the Iberian Peninsula – reviewing an old question from new laboratory and computational approaches

    G. Gonzalez-Fortes1, F. Tassi1, E. Trucchi1, A. Grandal D'Anglade2, J. Paijmans3, K. Henneberger3, C. Barroso1, A. Bettencourt4R. Fabregas4, A. Lombera4, M. Hofreiter3, G. Barbujani1

    In this study we investigated the demographic impact of the Neolithic transition in the Iberian Peninsula by combining cutting edge technologies in ancient DNA studies and statistical inference methods. The Neolithic was a major revolution in human prehistory, as human populations moved from a nomadic hunter-gatherer (HG) way of life to sedentary communities living on farming and agriculture. It was a global process that spread fast from the Near East into Europe by a combination of cultural and demographic events. As a general picture, recent studies have shown that in south and central Europe the Neolithic transition was mainly mediated by migration and admixture between pioneering farmers and local HG, while in the north and northeastern latitudes, cultural diffusion seems to have played a major role. In our study we investigated the dynamics and demographic effects of the Neolithic transition at a local scale. We sampled ancient human remains in the north and south of the Iberian Peninsula, and based on whole genome data and 14C dates, we have investigated the times, modes and demographic sources of the Neolithic diffusion at the two westernmost shores of Europe: the Atlantic and Mediterranean areas in Iberia. Our results show a different genomic background in samples from the North and South of the Iberian Peninsula, which could be explained by a combination of: 1) a different rate of admixture with the pioneering farmers; and 2) the pre-existence of some genetic structure in the Iberian populations before the Neolithic transition.
    Next big elephant in the room is the following:

    The genetic history of the Iberian Peninsula over the last 8000 years

    I. Olalde1, N. Rohland1, S. Mallick1,2,3, N. Patterson2, M. Allentoft4, K. Kristiansen5, K. G. Sjögren5, R. Pinhasi6, C. Lalueza-Fox7D. Reich1,2,3

    The Iberian Peninsula, lying on the southwestern corner of Europe, provides an excellent opportunity to assess the final impact of population movements entering the continent from the east and to study prehistoric and historic connections with North Africa. Previous studies have addressed the population history of Iberia using ancient genomes, but the final steps leading to the formation of the modern Iberian gene pool during the last 4000 years remain largely unexplored. Here we report genome-wide data from 153 ancient individuals from Iberia, more than doubling the number of available genomes from this region and providing the most comprehensive genetic transect of any region in the world during the last 8000 years.We find that Mesolithic hunter-gatherers dated to the last centuries before the arrival of farmers showed an increased genetic affinity to central European hunter-gatherers, as compared to earlier individuals. During the third millennium BCE, Iberia received newcomers from south and north. The presence of one individual with a North African origin in central Iberia demonstrates early sporadic contacts across the strait of Gibraltar. Beginning ~2500 BCE, the arrival of individuals with steppe-related ancestry had a rapid and widespread genetic impact, with Bronze Age populations deriving ~40% of their autosomal ancestry and 100% of their Y-chromosomes from these migrants. During the later Iron Age, the first genome-wide data from ancient non-Indo-European speakers showed that they were similar to contemporaneous Indo-European speakers and derived most of their ancestry from the earlier Bronze Age substratum.With the exception of Basques, who remain broadly similar to Iron Age populations, during the last 2500 years Iberian populations were affected by additional gene-flow from the Central/Eastern Mediterranean region, probably associated to the Roman conquest, and from North Africa during the Moorish conquest but also in earlier periods, probably related to the Phoenician-Punic colonization of Southern Iberia.

    So it seems there was a replacement rate of about 40% of the pre-Steppe bronze age genome by this incoming migrants. However, I don't think the statement above means that Bronze Age Iberians were 40% Yamnaya, but that Bronze Age Iberians were 40% Central European Beakers, who in turn are ~50% Yamnaya-like. Thus Bronze Age Iberians were on average about 20% Yamnaya. This is in line with the few results we have seen coming from Beaker genomes in Iberia with Steppe ancestry. Now, the sampling of the very first non-Indo-European speakers is key here! If this are Iberians genomes, as in from the Iberian tribes, then I think the non-difference between contemporary Indo-European speaking population and non-Indo-European speaking population shows that either the diffusion of Indo-European languages in Iberia had little gene flow during the Iron Age, or that non-Indo-European speaking Iberians were also from the same stock population. The high degree of similarity between Iron Age Iberians and Bronze age Iberians posits a dilemma. Either:

    1) Indo-European languages were brought over during the Bronze Age expansion starting at 2500 BCE and then non-IndoEuropean languages arrive much later in small proportions and were adopted by the majority of the population, thus resulting a majority Non-Indo-European speaking population with a Steppe-component like their Indo-European speaking neighbors. Perhaps Lusitanian and Tartessian are vestiges of this first Indo-European layer.

    2) The Bronze Age migrants from Central Europe spoke a non-Indo European language to begin with, and did not change the language landscape in Iberia. Then starting during the Urnfield culture, and proceeding with the Hallstat & La Tene Migrations Indo-European languages were brought over to Iberia via elite dominance, therefore yielding the genetic similarity between non-IE and IE Iron Age Iberians.

    I think the lack of genetic differentiation between non-IE speaking Iron Age Iberians and IE speaking Iron Age Iberians opens a pandora's box, and I think that the link of R1b-DF27+Steppe= IE is not that clear in Iberia to begin with, if it were then we need to explain how large percentages of its population did not acquire the IE languages in spite of acquiring the IE gene footprint. I don't think Celt-Iberian, not Gallaecian are old enough to have come in the Bronze Age, Lusitanian is the only possibility, however again, assuming that the first wave was Lusitanian, and Celt-Iberian+other Celtic languages arrive via elite dominance, then one still has to explain the Iberian Language, the Aquitanian Language.

    In laymen terms, this isn't just about the pesky Basque anymore, add to them now the humongous amount of non-IE speaking Iberians who appear be no different from their IE speaking neighbors, which means they are likely R1b-DF27 derived and have Steppe Ancestry yet kept their nonIE language.

  2. The Following 15 Users Say Thank You to jeanL For This Useful Post:

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