First Farmers Facing the Ocean

By Razib Khan | June 27, 2011 1:28 pm

The image above is adapted from the 2010 paper A Predominantly Neolithic Origin for European Paternal Lineages, and it shows the frequencies of Y chromosomal haplogroup R1b1b2 across Europe. As you can see as you approach the Atlantic the frequency converges upon ~100%. Interestingly the fraction of R1b1b2 is highest among populations such as the Basque and the Welsh. This was taken by some researchers in the late 1990s and early 2000s as evidence that the Welsh adopted a Celtic language, prior to which they spoke a dialect distantly related to Basque. Additionally, the assumption was that the Basques were the ur-Europeans. Descendants of the Paleolithic populations of the continent both biologically and culturally, so that the peculiar aspects of the Basque language were attributed by some to its ancient Stone Age origins.

As indicated by the title the above paper overturned such assumptions, and rather implied that the origin of R1b1b2 haplogroup was in the Near East, and associated with the expansion of Middle Eastern farmers from the eastern Mediterranean toward western Europe ~10,000 years ago. Instead of the high frequency of R1b1b2 being a confident peg for the dominance of Paleolithic rootedness of contemporary Europeans, as well as the spread of farming mostly though cultural diffusion, now it had become a lynch pin for the case that Europe had seen one, and perhaps more than one, demographic revolutions over the past 10,000 years.

This is made very evident in the results from ancient DNA, which are hard to superimpose upon a simplistic model of a two way admixture between a Paleolithic substrate and a Neolithic overlay. Rather, it may be that there were multiple pulses into a European cul-de-sac since the rise of agriculture from different starting points. We need to be careful of overly broad pronouncements at this point, because as they say this is a “developing” area. But, I want to go back to the western European fringe for a moment.


As I stated above the Basques were long used as a Paleolithic “reference” by historical geneticists. That is, the deviation of a population from the Basques would be a good measure of how much admixture there had been from post-Paleolithic sources. Connections between Iberian populations and those of western and northern Europe were used to trace expansions out of the ecological refuges of modern humans during the Last Glacial Maximum ~20,000 years ago. Just goes to show how reliant we are on axioms which are squishier than we’d like to think.

Last fall I posted a result from Dodecad on the difference between French and French Basques (both from the HGDP). I’ve replicated this myself a few times now too:

The striking aspect is that the Basque are less cosmopolitan than the other French. This is evident in most of the runs of the HGDP Basque; they just have a “simpler” genetic heritage than other Western Europeans. Today Dienekes posted some results from the IBS Spanish data set in the 1000 Genomes. He suggests there are clearly a few Spanish Basques in there (I’ve highlighted them):

Recall that the Basques were exempt from inspection for “cleanliness of blood”, because they were presumed to lack Jewish or Moorish ancestry by virtue of being Basque. It seems that the Spanish IBS sample, like the Behar et al. Spaniards and Portuguese, do have some Moorish genetic imprint. This is not too surprising. The Moriscos might have been expelled in the early 17th century, but not before the majority had converted to Christianity over the centuries (in fact, some of the most virulent anti-Morisco partisans had Moorish ancestry themselves, and were particularly tainted by association with the remaining culturally unassimilated crypto-Muslims). All that being said, I suspect that the “West Asian” ancestry amongst the majority of the Spaniards is not due mostly to the Arab period (when of the majority of the settlers probably were Berbers or Arabicized Berbers), but to population impacts prior to that. By the time of the Roman conquest much of Spain was Celtiberian. I have low confidence in this assertion, but I am coming to believe that the Indo-Europeans brought a mix of East European and West Asian ancestry (or at least those two distinct strands which tend to shake out of ADMIXTURE in a broad array of European samples) to western Europe.

On a related note, Wave-of-Advance Models of the Diffusion of the Y Chromosome Haplogroup R1b1b2 in Europe:

Whether or not the spread of agriculture in Europe was accompanied by movements of people is a long-standing question in archeology and anthropology, which has been frequently addressed with the help of population genetic data. Estimates on dates of expansion and geographic origins obtained from genetic data are however sensitive to the calibration of mutation rates and to the mathematical models used to perform inference. For instance, recent data on the Y chromosome haplogroup R1b1b2 (M269) have either suggested a Neolithic origin for European paternal lineages or a more ancient Paleolithic origin depending on the calibration of Y-STR mutation rates. Here we examine the date of expansion and the geographic origin of hgR1b1b2 considering two current estimates of mutation rates in a total of fourteen realistic wave-of-advance models. We report that a range expansion dating to the Paleolithic is unlikely to explain the observed geographical distribution of microsatellite diversity, and that whether the data is informative with respect to the spread of agriculture in Europe depends on the mutation rate assumption in a critical way.

Really I’m waiting for more ancient DNA. These sorts of studies are starting to feel like rewarming cold pizza. Edible, but suboptimal. Next, Phylogeography of a Land Snail Suggests Trans-Mediterranean Neolithic Transport:

Background
Fragmented distribution ranges of species with little active dispersal capacity raise the question about their place of origin and the processes and timing of either range fragmentation or dispersal. The peculiar distribution of the land snail Tudorella sulcata s. str. in Southern France, Sardinia and Algeria is such a challenging case.

Methodology
Statistical phylogeographic analyses with mitochondrial COI and nuclear hsp70 haplotypes were used to answer the questions of the species’ origin, sequence and timing of dispersal. The origin of the species was on Sardinia. Starting from there, a first expansion to Algeria and then to France took place. Abiotic and zoochorous dispersal could be excluded by considering the species’ life style, leaving only anthropogenic translocation as parsimonious explanation. The geographic expansion could be dated to approximately 8,000 years before present with a 95% confidence interval of 10,000 to 3,000 years before present.

Conclusions
This period coincides with the Neolithic expansion in the Western Mediterranean, suggesting a role of these settlers as vectors. Our findings thus propose that non-domesticated animals and plants may give hints on the direction and timing of early human expansion routes.

So basically the snail hitched a ride from Sardinia to Algeria to France. I don’t think this is that surprising. First, it seems pretty obvious that a lot of the cultural expansion in the prehistoric period did not consist of the fission of villages along a continuous wave of advance, but involved leap-frogging to suitable nuclei from which the populations expanded. Imagine a rising flood where the lowest zones are inundated first, and then the higher peaks. Additionally, we shouldn’t presume that these expansion events were without conflict and institutional support. Consider that the expansion of farming across much of southern European Russia and Ukraine could only occur after the state had pacified, expelled, or assimilated, the mobile Turkic populations which were wont to extract unsustainable rents out of isolated and vulnerable peasant populations.

Finally, what’s up with the strong north-south differentiation across the Mediterranean basin, peaking in the west? It’s as if there were two waves of demographic and cultural advance which laid the ground work, and later perturbations haven’t disrupted that bedrock. It suggests to me the critical importance of lateral coastal transport in connecting cultural colonies, as opposed to more long distance jumps across the open sea. The latter were probably important for the transport of luxury goods and the exchange of memes, but not so much for the exchange of genes.

CATEGORIZED UNDER: Genetics, Genomics, Geography, History
  • Eurologist

    The West Asian component has a huge gradient within Central Europe itself, being nearly absent in the north, and probably lower 2,000-3,000 years ago. The Celts (and later movements after Roman collapse) may have brought more of the NW European component to Iberia, but not a significant amount of West Asian. Greek colonies and the Romans seem to be a much clearer choice. I think it is highly likely that most of Iberia genetically looked like the Basque do today, before Roman times.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    . Greek colonies and the Romans seem to be a much clearer choice.

    greek colonies. which spanish greek colonies? the latin influence souths plausible.

  • Eurologist

    In the sense that Greek colonies (and perhaps other seafarers) brought more of the Western Asian component to Italy and SE France, from where it could spread, later. It looks to me as if any neolithic/agricultural West Asian portion quickly petered out west of the Balkans.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    It looks to me as if any neolithic/agricultural West Asian portion quickly petered out west of the Balkans.

    fyi, germans more more than swedes, who have more than finns, which is none is finns. a non-trivial amount in austrian samples i’s got access too. i doubt massilia had much of an impact on that region of gaul. but magna graecia was a big deal for sure. though please note that the greeks generally did not bring women, so they got those from the natives often by hook or by crook. so that’s a dilution factor right there.

  • Paul Ó Duḃṫaiġ

    of course it doesn’t help that several years ago that we didn’t have the same resolution regarding sub-haplogroups of R1b1b2 for example Welsh and Irish mostly belong to R1b-L21 (M222 — Uí Néill– subgroup of L21) — R1b1a2a1a1b4

    Basques tend to belong to several Iberians specific SNP’s which appear to have been recently united under a newly discovered SNP (Z196) — interesting both it and L21 are under SNP called P312. The main division in western Europe R1b is between P312 and it’s subhaplotypes and U106. U106 has more of a “germanic imprint” in Europe.

    http://ytree.ftdna.com/index.php?name=Draft&parent=23808881

    I’m L21* myself, so far I’ve tested negative for all know new sub-haplotypes under L21 (FamilytreeDNA)

  • http://www.parhasard.net/ Aidan Kehoe

    Looks like the Greeks did have colonies in Spain: http://en.wikipedia.org/wiki/Colonies_in_antiquity . But the Phoenicians would be a better bet for West Asian DNA.

  • Eurologist

    The most important thing to notice is that today, gradients of the West Asian component are steep both from the Balkans through central Europe and the North, and along the northern Mediterranean shores. It is reasonable to expect that what we see today conforms to 2,000 to 8,000 years of diffusion – i.e., Western Asian components necessarily were much less then in Europe, but with sharper gradients.

  • chris y

    The Greeks founded colonies everywhere they could reach, and the Carthaginians controlled the western Mediterranean for centuries (Spanish place names like Barcino – mod. Barcelona – and Cartagena are a bit of a clue). But neither group settled inland much. Even the Romans didn’t really settle Spain beyond Andalusia and the Atlantic and Mediterranian coasts much. They claimed it; they stationed a legion to guard the gold mines in the north (Leon), but they didn’t much make themselves at home. Yet the map at the top of this post doesn’t show much differentiation between the coast and the hinterland. What’s that about?

  • toto

    Dodecad shows a strong West Asian component in Germany and in the British Isles, including Ireland. If it got there (presumably without Greco-Roman help), then it may well have gotten to Spain without Greco-Roman help as well?

    There is about the same aount of W Asian component between Germans, English and Irish, so presumably its presence in the British Isles is not merely an effect of Germanic invasions. It got there before.

    Notice that the W Asian component is strong in the Middle East and tapers down in W Europe – then abruptly disappears in non Indo-European populations (Finns and Basques). This differs from the pattern shown in the picture at the top of this post, where a supposedly Middle Eastern gene has almost vanished from the Middle East (presumably to be displaced by later innovations), but is strong in the Basque country (FR1 lies right on it!).

    A small, but culturally determinant Indo-European wave (W Asian component) following an earlier, stronger, mass-replacement Neolithic wave (R1b1b2)? Why not?

  • Lassi Hippeläinen

    “Yet the map at the top of this post doesn’t show much differentiation between the coast and the hinterland. What’s that about?”

    Maybe some later mixing? Quite a few armies have romped through Spain in later centuries.

    But what about Iceland? They are a mix of Norse and Irish blood, but usually it is taken to mean that the Vikings raided Ireland and carried some female slaves to Iceland. But that should show in mtDNA, not Y. Did the Irish monks in Iceland get a piece of the action?

  • Naughtius Maximus

    Lassi, there is the legend of Saint Brendan who many like to believe landed in North America. It’s likely he made it to Iceland.

  • Ezequiel

    In Spain, population density is much higher on the coast than inland. Inland is pretty mountainous, with sierras close to the coast blocking communications to the meseta, the central highland, except from the West. Most large cities are in the coast or a short trek up a large river, except Madrid, which was a small town before becoming the Court.

    The greeks and phoenicians only created colonies in the coast, but I can see how they could leave a supersized genetic imprint, as the locals sought and obtained status by family ties with the very rich foreigners. And high status meant high reproductive rates back then, right?

    And later conflicts depopulated regions of the central highland, so much that it was called the “Desert of the Duero” (http://en.wikipedia.org/wiki/Repoblaci%C3%B3n).

    This is a very interesting topic for me, being half Basque, half Malagueño (a phoenician colony)!

  • carpetanuiq

    Nice post. However the wikipedia link you point to is somewhat confusing.

    Moriscos was a religious identity, not really racial. As you say arab and bereber influx during islamic times was limited. Most historians consider now that moriscos (both those expulsed to North Africa and those which remained in Spain) went trough the folowing conversion path as history unfolded: christians under goths > muladies > mudejares > moriscos> since XVIII christians again (during and more after XVIII century nobody really bothered about these issues).

    Navarra and basque provinces were different political entities during lower middle ages and Ancient Régime (they remain different regional political entities today). Hidalguia universal was a feature of basque provinces (not sure if in all Alava), but not of Navarra in general, ony in some valleys, most in the frontier with France (Baztán, Roncal and some others). It was possibly a way to assure loyalty in poor and hard to access for tax levy areas (we must not forget the economic dimension of hidalguia, more important in some cases than the honorific: they were exempt from taxation). Navarra had a nobility system, more akin to french than to castillian, but nobility anyway. Another province with hidalguia universal was Asturias, poor, hard to access and excentric to most used routes had the same institution.

    As for the caste society in the colonies it is interesting to note that it lacks the features of a real caste society: identification of reproduction with profession. I wonder what would had happened if this society had evolved in isolation.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    Moriscos was a religious identity, not really racial. As you say arab and bereber influx during islamic times was limited. Most historians consider now that moriscos (both those expulsed to North Africa and those which remained in Spain) went trough the folowing conversion path as history unfolded: christians under goths > muladies > mudejares > moriscos> since XVIII christians again (during and more after XVIII century nobody really bothered about these issues

    i think it is is arguably racial in enough contexts that you shouldn’t confuse the ignorant by reducing it to pure confession. there were professing christian moriscos who were expelled, including children. the criterion was that of ethnicity attached to a proto-national/religious identity.

    As for the caste society in the colonies it is interesting to note that it lacks the features of a real caste society: identification of reproduction with profession.

    xan you clarify?

  • ackbark

    It’s been a while, but, as I recall, the story of the origins of the Britons in Geoffrey of Monmouth was that they originate as a population fleeing the fall of Troy, land on the south coast of Spain, have some adventures along the western coast of Gaul, wander through Ireland, then into Britain.

    Which could correspond neatly with the map up above.

  • Grey

    As others have mentioned Carthage had a lot of colonies along the North African and Spanish coasts and the Greeks had at least one (at Emporium IIRC). It was trade conflicts between these colonies that got Rome involved in Spain.

    That may or not be it. I’d guess not.

    The way i look at it is if you imagined a large relief model of that map and covered it in red paint. Then, before it was dry, you got six buckets of white paint and you
    – stood SE of Greece and threw one bucket roughly north-west
    – stood S of Spain and threw one north-east
    – stood south of Italy and threw one bucket north
    – stood somewhere around Germany/Poland and threw three buckets roughly south-west, south and south-east,
    then i think you’d roughly get your map colors with mountainous terrain blocking the flow and the remotest regions from where you threw the paint having the least overlay.

    If farming didn’t spread by diffusion then there must be at least two waves from north africa/near-east, the paleolithic hunter-gatherers and the neolithic farmers (and possibly multiple waves). Assuming they pushed out the paleos through greater numbers they’d follow the sort of vectors you mention i.e. coastal first then up rivers then a circular expansion from colony sites everywhere non-mountainous leaving behind clumps of legacy population in places like the Pyrenees and Alps and in the remotest western edge.

    Not sure how that fits.

    I think there are two directions of intrusion. Some of the northern population folded back on the south in the same way the Bantus did to the Khoi and the north africans and Arabs did to the Bantus etc. This seems to be quite common.

  • Grey

    Another point i just thought of that fits the map. When Caesar described Gaul he said there was a clear division into three visibly distinct groups: Gauls, Belgae and Vascones with the Vascones at the time being the mountain Basques plus a large extension along the south-west and west of modern France

    http://en.wikipedia.org/wiki/Vascones

    http://www.1stforgascony.com/wp-content/themes/mimbo2.2/images/leadpic.jpg

    If you think of settlers following the path of least resistance coming from the near east then the expansion routes would be coastal first, followed (imo) by going up rivers. If you look at France in the context of mountains being road-blocks and rivers being the roads

    http://www.planetware.com/i/map/F/basins-mountains-and-rivers-in-france-map.jpg

    then i think you can see a geographical reason for the distinctiveness of the Vascones and a possible correlation with your R1 map. There’s a narrow coastal zone along the south of France with the main way out of that zone (if you’re coming from the direction of the mediterranean) being north up the Rhone. If you then made a hop to the Loire near Lyon and follow it downstream (and its various tributaries upstream when you came to them) then i think it’s clear the Aquitanian basin and the Armorican Massif might have been among the last places settled whether it was neolithic intruding on paleo or later waves of neolithic intruding on earlier waves.

  • Grey

    Last thought. There’s this idea of neolithic farmers replacing paleolithic hunter-gatherers and a possible second idea of multiple neolithic waves however i would have thought one of the candidates for a first wave wouldn’t be farmers but pastoralists.

    I don’t know which of plants or animals is supposed to have come first in the near-east but either way, pastoralists have advantages of mobility and the ability to subsist off lower quality terrain, especially if they are not stopping long. Also, although they’d have a lower population density than farmers they’d still (i think?) have a higher one than hunter-gatherers so if they were pushing them off their terriotory they’d have the advantage of numbers.

    So first wave pastoralists pushed into refuges by second wave farmers maybe? If so that might tie in with distributions of lactose tolerance with the first wave refuges having higher quantities followed by a dip among the surrounding neolithic farmers followed by a rise again among IE pastoralists.

  • carpetanuiq

    Sorry for late reply.

    “there were professing christian moriscos who were expelled, including children. the criterion was that of ethnicity attached to a proto-national/religious identity”.

    (Prologue diclaimer: I hope my answer is not interpreted as a defense of the expulsion nor a justification; I´m just trying to argue that according to the avalaible data race was not the main issue, if it was an issue at all)

    The Morisco ethnicity was not monolithic at the time. There were mainly four subgroups: old-castille moriscos, valencian, aragonese and those from Granada. Castillian moriscos were low to middle class, well integrated in their environment, with considerable intermarriage rate with old christians, loosing smoothly their past religious identity. I know less about the situation of those from valencia and aragon, probably more in the lower class. Those less integrated were those from granada, which had even revolted decades ago.

    These revolts together with some cripto-practices in all the subgroups and the geopolitical context (Ottmans getting more and more powerfull in the mediterranean) were possible causes of the expulsion. Posibly a mixture: theologians for religious reasons, high-bureaucrats for geopolitical reasons and low-bureaucrats (if they had any share in the decision for competition for positions reasons; despite regulations conversos of any religion were occupying bureaucratic postions). In a situation were they could not know how extended were criptopractices they took the, no doubt unfair, elite decision of expulsing them all. In any case it is fair to say that there is not full agreement among historians about the reasons and motivations of the expulsion, the case beeing still under research.

    The chidren matter was under discussion at the time and in fact many childrens were not expulsed (an interesting link about this for those who read spanish: http://www.ignasigirones.com/htm/morisquillos.htm). The reason for those favouring the no expulsion of childrens was preciselly that you could not nd judge innocent childrens for the guilty criptopractices of their fathers. Those arguing for the expulsion of children did it for “humanitary” reasons: how could you separe fathers and childrens.

    To conclude, pure racial issues, if they existed were very secondary. Ethnic issues (such as clothes, cuisine, language…) could be more important, since they could be signals of criptopractices (therefore subordinated to religious issues).

    p.s.
    Regarding the caste I would need probably a longer and more elaborated answer. Let´s drop this issue for another occasion.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    To conclude, pure racial issues, if they existed were very secondary. Ethnic issues (such as clothes, cuisine, language…) could be more important, since they could be signals of criptopractices (therefore subordinated to religious issues).

    i never said it was a pure racial issue. where did i say that? you seem to be responding to an assertion i never made. i’ve read the academic literature in this area, so yeah, i’m broadly familiar with some of these issues, you fleshed out some regional details (i knew mostly valencia and aragon).

  • carpetanuiq

    Razib, you did not said it, I was just refering to the article from wikipedia.

    To end, another example that the concept of “limpieza de sangre”, despite its name had was really diferent from racism was that, besides religion cleanliness it included to be clean from ancestors that had occupied “dirty” professions. Many old-christians which became rich on trade or in the handcrafts had to clean their blood when they wanted to entry in some noble corporations. At this times there existed many identitary frontiers, but I do not think race was that important.

    For those interested in this area, I would suggest, if I may, regarding old-castillan moriscos (many of them concentrated around Avila), Serafin de Tapia article´s (I do not know if they are translated into english). For Castilla-la Mancha (the new castilla) a good start could be “Mudejares y moriscos en Castilla La Mancha” from Romero Saiz.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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