Long-term matrilineal continuity in a nonisolated region of Tuscany

iron_age_europe_mediterranean

New paper (behind paywall) The female ancestor’s tale: Long‐term matrilineal continuity in a nonisolated region of Tuscany, by Leonardi et al. Am J Phys Anthr (2018).

EDIT (10 SEP 2018): The main author has shared an open access link to read the PDF.

Interesting excerpts:

Here we analyze North-western Tuscany, a region that was a corridor of exchanges between Central Italy and the Western Mediterranean coast.

We newly obtained mitochondrial HVRI sequences from 28 individuals, and after gathering published data, we collected genetic information for 119 individuals from the region. Those span five periods during the last 5,000 years: Prehistory, Etruscan age, Roman age, Renaissance, and Present-day. We used serial coalescent simulations in an approximate Bayesian computation framework to test for continuity between the mentioned groups.

In all cases, a simple model of a long-term genealogical continuity proved to fit the data better, and sometimes much better, than the alternative hypothesis of discontinuity.

The low number of samples analyzed requires some caution in the interpretation. Because we did not test for gene flow, it is at this stage impossible to reject it, but our results suggest at least significant levels of genealogical continuity. Moreover, as it has not been possible to obtain more precise information on the age of the Eneolithic samples, they were grouped together considering the average archaeological period of interest, which may cause a bias in the analyses. (…)

tuscany
Geographic location of the samples considered in this work

(…) clearly, our samples show high levels of continuity when considering the whole Tuscan region as a genetic reservoir during the Iron Age.

The posterior distributions of the parameters confirm a high degree of genetic isolation in the sampled population, with very small values for the female effective population sizes across time. Such values, in particular the Neolithic ones, are in accord with the estimates obtained in similar studies, both in Tuscany (Ghirotto et al., 2013) and in France (Rivollat et al., 2017).

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Taken at their face value, our results do not show any major shift in the composition of the maternal ancestry of the population, across 50 centuries. This does not mean that no demographic process of relevance has affected the population, and indeed the higher diversity accumulating in time is the likely consequence of immigrating people, enriching the mitochondrial gene pool.

(…) the population of the current Lucca province appears to have retained very ancient mitochondrial features, despite occupying a geographical corridor between the Ligurian and the Tyrrhenian coast, and despite not showing the persistence of unique cultural traits through the centuries.

tuscany-genetic-diversity-hap

Another possibility is that that the different populations passing through the area (Etruscans, Romans, and Lombards) had a consistent social and/or sex bias. An example of similar patterns has been observed several times. Between the Late Neolithic and the Early Bronze Age, female exogamy in patrilocal society has been observed in Southern Germany (Knipper et al., 2017); during the Bronze Age the migrations toward Europe from the steppes appears to have consisted prevalently of males (Goldberg, Günther, Rosenberg, & Jakobsson, 2017); and in more recent periods in the Canary Islands, the female ancestry maintains a significant amount of autochthonous lineages, while the male ancestry was strongly influenced by the European colonization (Fregel et al., 2009, b).

It is well known that military invasions may not have a significant genetic impact upon the invaded population (Schiffels et al., 2016; Sokal, Oden, Walker, Di Giovanni, & Thomson, 1996;Weale,Weiss, Jager, Bradman, & Thomas, 2002), especially at the mitochondrial level, because of the limited size of a sustainable army, and of the fact that armies are generally composed mostly or only of males. Even if a substantial share of invaders decided to remain and settle the region, this form of gene flow would affect mostly or only the paternal lineages, rather than the maternal ones. We can also hypothesize the immigration of a number of people (e.g., Romans, Lombards) that may have acted as ruler of the region, remaining socially (and so genetically) separated by the local population, and leaving few (if any) traces in the gene pools of the local population.

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Supporting Information, Table S1 New ancient samples genotyped

We expect to see that certain migrations since the Iron Age – like the Celtic and Roman ones – were somehow different from previous ones, where, at least since the Neolithic, male-dominated expansions were the rule.

If, however, male-biased expansions are also seen during the Iron Age – probably driven by particular subclades then – , this would certainly justify the continuity of admixture in certain regions in spite of these population expansions, and thus the importance of Y-DNA to track more recent language changes.

One of the most interesting details of the upcoming paper of Italic peoples will be the Y-DNA (and admixture) of Etruscans compared to other neighbouring peoples, given the known conflicting theories regarding their recent vs. older origin in the East before the historical record.

Related

Bayesian estimation of partial population continuity by using ancient DNA and spatially explicit simulations

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Open access Bayesian estimation of partial population continuity by using ancient DNA and spatially explicit simulations, by Silva et al., Evolutionary Applications (2018).

Abstract (emphasis mine):

The retrieval of ancient DNA from osteological material provides direct evidence of human genetic diversity in the past. Ancient DNA samples are often used to investigate whether there was population continuity in the settlement history of an area. Methods based on the serial coalescent algorithm have been developed to test whether the population continuity hypothesis can be statistically rejected by analysing DNA samples from the same region but of different ages. Rejection of this hypothesis is indicative of a large genetic shift, possibly due to immigration occurring between two sampling times. However, this approach is only able to reject a model of full continuity model (a total absence of genetic input from outside), but admixture between local and immigrant populations may lead to partial continuity. We have recently developed a method to test for population continuity that explicitly considers the spatial and temporal dynamics of populations. Here we extended this approach to estimate the proportion of genetic continuity between two populations, by using ancient genetic samples. We applied our original approach to the question of the Neolithic transition in Central Europe. Our results confirmed the rejection of full continuity, but our approach represents an important step forward by estimating the relative contribution of immigrant farmers and of local hunter‐gatherers to the final Central European Neolithic genetic pool. Furthermore, we show that a substantial proportion of genes brought by the farmers in this region were assimilated from other hunter‐gatherer populations along the way from Anatolia, which was not detectable by previous continuity tests. Our approach is also able to jointly estimate demographic parameters, as we show here by finding both low density and low migration rate for pre‐Neolithic hunter‐gatherers. It provides a useful tool for the analysis of the numerous aDNA datasets that are currently being produced for many different species.

central-european-neolithic
A) Different zones defined for computing proportions of ancestry in Central Europeans 4,500 BP. B) Schematic representation of various population contributions. C) Mean proportions of ancestry from the various PHG zones (A+B+C+D) in Central European populations from zone A at the end of the Neolithic transition 4,500 BP, computed for autosomal and mitochondrial markers.

Relevant excerpts:

Our results are in general accordance with two distinct ancestry components that have previously been detected at the continental scale by Lazaridis, Patterson et al. (2014): the “early European farmer” (EEF), which corresponds here to the NFA from Anatolia (zone C in Figure 3), and the “West European hunter-gatherer” (WHG), which corresponds here to the PHG from zones A and B in Figure 3. Notably, the contribution of an Ancient North Eurasians (ANE) component is not included in our model as we did not consider potential post-Neolithic immigration waves, which could have contributed to the modern European genetic pool, such as the wave that came from the Pontic steppes and was associated with the Yamnaya culture (Haak, Lazaridis et al. 2015). Without considering the ANE ancestry component, our estimate of the autosomal genetic contribution of Early farmers to the gene pool of Central European populations (25%) tends to be lower than the EEF ancestry estimated in most modern Western European populations, but is of the same order than the estimations in modern Estonians and in the ancient Late Neolithic genome “Karsdorf” from Germany (Lazaridis, Patterson et al. 2014, Haak, Lazaridis et al. 2015). Note that the contribution of hunter-gatherers to Neolithic communities appears to be variable in different regions of Europe (Skoglund, Malmstrom et al. 2012, Brandt, Haak et al. 2013, Lazaridis, Patterson et al. 2014), while we computed an average value for Central Europe. Moreover, we computed the ancestry of the two groups at the end of the Neolithic period while previous studies estimated it in modern times. Finally, previous studies used molecular information to directly estimate admixture proportions, while we use molecular information to estimate the model parameters and, then, we computed the expected genetic contributions of both groups using the best parameters, without using molecular information during this second step. Model assumptions may thus influence the inferences on the relative genetic contribution of both groups. In particular, we made the assumption of a uniform expansion of NFA with constant and similar assimilation of PHG over the whole continent but spatio-temporally heterogeneous environment, variable assimilation rate and long distance dispersal may have played an important role. The effects of those factors should be investigated in future studies.

Reactionary views on new Yamna and Bell Beaker data, and the newest IECWT model

You might expect some rambling about bad journalism here, but I don’t have time to read so much garbage to analyze them all. We have seen already what they did with the “blackness” or “whiteness” of the Cheddar Man: no paper published, just some informal data, but too much sensationalism already.

Some people who supported far-fetched theories on Indo-European migrations or common European haplogroups are today sharing some weeping and gnashing of teeth around forums and blogs – although, to be fair, neither Olalde et al. (2018) nor Mathieson et al. (2018) actually gave any surprising new data that you couldn’t infer before… People are nevertheless in the middle of the five stages of grief (for whatever expectations they had for new samples), and acceptance will surely take some time.

They will be confronted with two options:

  1. Keep fighting for what they believed, however wrong it turns out to be – after all, we still see all kinds of autochthonous continuists out there, no matter how much data there is against their views. People want to be supporters of a West European origin of R1b-M269 linked to Vasconic languages, fans of R1b-M269 continuity in Central Europe, Uralic speakers who believe in hidden N1c communities in Mesolithic or Neolithic Eastern Europe, fans of the OIT and Indian origins of R1a-M417…
  2. Just accept what seems now clear, change their model, and go on.
wiik-modified
Modified from Wiik for the current autochthonous continuity fans: Vasconic-Uralic distribution and Indo-European folk distribution

For me, the second option sounds quite simple, since whatever happens – markers of Indo-European migration being R1a or R1b, Corded Ware or Bell Beaker, or bothour group’s aim for the past 15 years or so is to support a North-West Indo-European proto-language, so any of the most reasonable anthropological models are a priori compatible with that. My model of Indo-European demic diffusion fits best the most recent proto-language guesstimates, though.

However, I understand that if I had been buying or selling dreams – and I mean literally buying or selling fantasies of whiteness and Europeanness (hidden behind an idealized concept of “Indo-European”, and ancestral components disguised as populations), beginning with the ‘R1a-M417/CWC’ and ‘Yamnaya ancestry’ craze of the 2015 papers – , and I realized data didn’t support that money exchange, I would be frustrated, too.

There is a funny mental process going on here for some of these people, as far as I could read today. Let me review some history of the Indo-European question here before getting to the point:

  1. Firstly linguists reconstructed (and are still doing it) Proto-Indo-European and other ancestral Indo-European proto-languages.
  2. Then archaeologists tried to identify certain ancestral cultures with these actual communities with help from linguistic guesstimates and dialectal classifications,
  3. using anthropological models of migration or cultural diffusion.
  4. Then genetic data came to support one of these alternative anthropological models, if possible.

Now some (amateur) geneticists are apparently disregarding what “Indo-European” means, and why Yamna was considered the best candidate for the expansion of Late Indo-European languages, and question the very sciences of Linguistics and Archaeology as unreliable, instead of questioning their own false assumptions and wrong interpretations from genetic papers.

Really? Genomics (especially ancestral components) now defines what an Indo-European population, culture, and language is? If that is not a fallacy of circular reasoning, I wonder what is.

The modified IECWT model

The surprise today came from the quick reaction of one member of the IECWT workgroup, Guus Kroonen, in his draft Comments to Olalde et al. 2018., The Beaker phenomenon and the genomic, transformation of northwest Europe, Nature.

Allentoft Corded Ware
The IECWT workgroup’s so-called “Steppe model” until today, as presented in Haak et al. (2015).

He and – I can only guess – the whole IECWT workgroup finally rejected their characteristic Corded Ware -> Bell Beaker migration model – which they defended as “The steppe model” of Indo-European migration in Haak et al. 2015. They now defend a proposal similar to Anthony (2007).

Fan fact: Anthony changed his mind recently to partially support what Heyd said in 2007. While I did not dislike Anthony’s new model, I consider it wrong.

The Danish group – unsurprisingly – sticks nevertheless to the hypothesis of some kind of autochthonous Germanic in Scandinavia being defined by Corded Ware migrants and haplogroup R1a, and being somehow special and older among Proto-Indo-European dialects because of its non-Indo-European substrate – although in fact Kroonen’s original linguistic paper didn’t imply so.

While this new change of the workgroup’s model brings it closer to Heyd (2007), and parallels in that sense the adaptation process of Anthony (but always one step behind), what they are proposing right now seems not anymore a modified Kurgan model, as I described it: it is essentially The Kurgan model of Marija Gimbutas (1963), with Bell Beakers spreading a language ancestral to Italo-Celtic, and Corded Ware spreading some kind of mythical Germano-Balto-Slavic

I find it odd that he would not cite Gimbutas, Heyd – as Anthony recently did – , or the most recent paper of Mallory on the language expanded with Bell Beakers, but just the workgroup’s papers and other old ones, to present this “new” theory.

However simple and (obviously) rapidly drafted it was, following the publications in Nature, it does not seem right: They were first, they were right, acknowledge them. Period.

It is interesting how the wrong interpretations of the ‘Yamnaya ancestral component’ (you know, that bulletproof “Yamna R1a-R1b community” and Yamna->Corded Ware migration that never happened) is affecting everyone involved in Indo-European studies.

Related:

Another nail in the coffin for the Anatolian hypothesis: continuity and isolation in the Caucasus during the Neolithic and Calcholithic, in mtDNA samples

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A new paper appeared on Current Biology, by Margaryan et al. (including Morten E. Allentoft): Eight Millennia of Matrilineal Genetic Continuity in the South Caucasus.

Among its conclusions:

The plot clearly shows the clustering of the ancient group together with the modern European, Armenian, and Caucasian populations. We observe none of the typical East Eurasian mtDNA lineages (A, C, D, F, G, and M) among the ancient individuals, and only one individual with haplogroup D is present in the modern Armenian maternal gene pool (Artsakh). As such, the archaeologically and historically attested migrations of Central Asian groups (e.g., Turks and Mongols) into the South Caucasus [14, 15] do not seem to have had a major contribution in the maternal gene pool of Armenians. Both geographic (mountainous area) and cultural (Indo-European-speaking Christians and Turkic-speaking Muslims) factors could have served as barriers for genetic contacts between Armenians and Muslim invaders in the 11th–14th centuries CE. The same pattern was observed using Y chromosome markers in geographically diverse Armenian groups.

Also, regarding the potential Indo-European migration into the area:

It appears that during the last eight millennia, there were no major genetic turnovers in the female gene pool in the South Caucasus, despite multiple well-documented cultural changes in the region [27, 28]. This is in contrast to the dramatic shifts of mtDNA lineages occurring in Central Europe during the same time period, which suggests either a different mode of cultural change in the two regions or that the genetic turnovers simply occurred later in Europe compared to the South Caucasus. More data from earlier Mesolithic cultures in the South Caucasus are needed to clarify this. During the highly dynamic Bronze Age and Iron Age periods, with the formation of complex societies and the emergence of distinctive cultures such as Kura-Araxes, Trialeti-Vanadsor, Sevan-Artsakh, Karmir-Berd, Karmir-Vank, Lchashen-Metsamor, and Urartian, we cannot document any changes in the female gene pool. This supports a cultural diffusion model in the South Caucasus, unless the demographic changes were heavily male biased, as was most likely the case in Europe during the Bronze Age migrations [29, 30]. However, genome-wide data from the few Bronze Age individuals published so far from the South Caucasus also support a continuity scenario [26]. Another possibility is that any gene flow into the South Caucasus occurred from groups with a very similar genetic composition, facilitating only subtle genetic changes that are not detectable with the current datasets.

I would obviously support the latter possibility, a demic diffusion that can be shown by precise subclade and admixture analyses, because cultural diffusion is quite difficult to justify in any ancient setting. Since it is most likely south-eastern European R1b-Z2103 lineages (or R1b-M269, if resurged during the proto-language transition in the Balkans) the original marker of Palaeo-Balkan speakers, that is what one should be looking for in Y-DNA investigation in the area. Since migrations were probably male-biased, it is not likely that mtDNA was much affected. But, especially during the Iron Age, a change should also be seen, marked by the appearance of (recent) U subclades.

Related:

The Aryan migration debate, the Out of India models, and the modern “indigenous Indo-Aryan” sectarianism

On the origin of R1a and R1b subclades in Greece

News of the article seen first in Eurogenes (you can see the specific samples there).

Featured image is from the article.